MECHANICAL ENGINEERING DEPARTMENT AT THE UNIVERSITY OF MAINE
2012 Clean Snowmobile
Rebuilding the 2007 Yamaha Phazer for CSC
Michael Galli, Kalee Gurschick, Andrew Gwarjanski, Lucas Farrar, David Raymond
5/1/2012
ABSTRACT:
The challenge of a damaged 2007 Yamaha Phazer left by the previous clean snowmobile team was taken on by
an inexperienced group of seniors. The 2012 team was essentially starting from scratch, attempting to return
the sled to working condition. This document provides all of the work done this year and can be used by future
teams as reference material to continue to improve the machine for competition.
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Table of Contents
1.0 Introduction ..........................................................................................................................................................1
1.1 SAE Clean Snowmobile Challenge ....................................................................................................................1
1.2 Project Overview ..............................................................................................................................................1
1.3 2012 CSC Team Goals .......................................................................................................................................3
2.0 Reassemble Sled ...................................................................................................................................................4
2.1 Rebuilding Engine .............................................................................................................................................4
2.2 Wiring ...............................................................................................................................................................6
2.2.1 Overview....................................................................................................................................................6
2.2.2 New Sensors Added ...................................................................................................................................7
3.0 Fix Engine Control System ....................................................................................................................................7
3.1 Sensor Calibrations ...........................................................................................................................................7
3.2 MicroSquirt Firmware ................................................................................................................................... 10
3.2.1 Selecting the Firmware ........................................................................................................................... 10
3.2.2 Installing the Firmware ........................................................................................................................... 10
3.3 Tunerstudio Setup ......................................................................................................................................... 11
3.3.1 Initial Set-Up ........................................................................................................................................... 11
3.3.2 Calibrating Sensors ................................................................................................................................. 11
3.3.3 Fuel Set-Up ............................................................................................................................................. 12
3.3.4 Ignition Set-Up ........................................................................................................................................ 20
3.4 Tuning MicroSquirt ........................................................................................................................................ 23
3.4.1. Overview................................................................................................................................................ 23
3.4.2 VE Table .................................................................................................................................................. 24
3.4.3 AFR Table ................................................................................................................................................ 25
3.4.4 Warm-up Wizard .................................................................................................................................... 25
3.4.5 Acceleration Wizard ............................................................................................................................... 26
3.4.6 Cold Advance .......................................................................................................................................... 27
3.4.7 IAT-Based Fuel Correction/ IAT-Based Timing Retard ............................................................................ 27
3.5 MegaLog Viewer ............................................................................................................................................ 28
4.0 Ethanol............................................................................................................................................................... 28
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4.1 Theory ............................................................................................................................................................ 28
4.2 Testing for Ethanol Content .......................................................................................................................... 30
5.0 Cowling Repair ................................................................................................................................................... 31
5.1 Initial State of 2011 Team’s Cowlings ............................................................................................................ 31
5.2 Repair and Painting Process .......................................................................................................................... 31
6.0 Fuel Injectors ..................................................................................................................................................... 33
6.1 Determination of Fuel Pump Pressure .......................................................................................................... 33
6.2 Baseline Fuel Flow at Diesel Fuels ................................................................................................................. 35
6.3 Custom Flow Bench ....................................................................................................................................... 37
6.3.1 Concept................................................................................................................................................... 37
6.3.2 Fabrication .............................................................................................................................................. 38
6.3.3 Flow Bench Wiring .................................................................................................................................. 38
6.3.4. Testing ................................................................................................................................................... 39
7.0 Exhaust Systems ................................................................................................................................................ 44
7.1 Stock Exhaust ................................................................................................................................................. 44
7.2 Custom Exhaust ............................................................................................................................................. 45
8.0 Conclusion ......................................................................................................................................................... 46
References ............................................................................................................................................................... 47
Appendices ............................................................................................................................................................. A.1
Appendix A: Engine Assembly ............................................................................................................................ A.1
Appendix B: Flow Bench Parts Details ................................................................................................................ B.1
Appendix C: Custom Exhaust Parts..................................................................................................................... C.1
Appendix D: Budget ............................................................................................................................................ D.1
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1.0 Introduction
1.1 SAE Clean Snowmobile Challenge
The SAE Clean Snowmobile Challenge (CSC) is an annual event held at Michigan Technological
University’s Keweenaw Research Center. Two categories of sleds compete at the CSC, Internal Combustion and
Zero-Emissions. The University of Maine has regularly entered in the Internal Combustion Category. In this
category, the teams must be able to run on fuel with higher contents of ethanol than stock gasoline. This is
generally around 20% to 30% ethanol. The five main categories of competition include Handling, Endurance,
Acceleration, Noise and Emissions. The teams must also present their snowmobile in a static display and provide
a design paper for judging. [9]
1.2 Project Overview
The goal of the clean snowmobile project year after year has been to modify what was once a stock
2007 Yamaha Phazer snowmobile into a machine worthy of the SAE Clean Snowmobile Challenge. Past
alterations to the Yamaha Phazer have included the addition of a MicroSquirt engine control unit, catalytic
converters and custom-built cowlings. Along with the modifications, the goal has also been to document and
provide theoretical support of these changes taken towards creating a well-functioning and environmentallyfriendly snowmobile. This year's initial goal of competing in SAE's annual Clean Snowmobile Challenge was
overrun by the problems encountered by the previous year’s team.
This is the fifth year the 2007 Phazer has been used for a capstone project. During the endurance run
portion of the 2011 SAE Clean Snowmobile Competition, the snowmobile experienced problems. Due to an
extremely high air-fuel ratio, the engine experienced overheating, ultimately leading to one of the pistons being
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damaged. The severity of the damage ended the team’s ability to compete. After returning from the 2011 CSC,
the 2011 team removed the engine, disassembled it, and due to a delay in parts from Yamaha, left it for the
following year’s students to repair.
The 2012 University of Maine's SAE Clean Snowmobile team undertook the arduous task of taking a
heavily modified snowmobile, with inadequate documentation of the 2011 changes that had been made, and
delivering a competition quality machine, ready for the 2013 team to modify as needed.
The 2007 Yamaha Phazer was left by the 2011 Team in a broken down state, as shown below in Figure 1.
The engine was completely torn apart and stored in boxes. There was little documentation as to what actually
went wrong and how to fix it. The engine needed to be assembled as well as making all the wiring connections.
Without previous knowledge of part placement before the machine was disassembled, it was quite a challenge.
The engine control settings were also not documented consistently. The files that did exist were not clearly
labeled with dates, so there was no clear starting point. The cowlings had also been damaged and slightly
restored. Of the three cowlings, none were at the same stage of repair. The 2011 team also left a damaged
exhaust system, including a pre-catalytic converter and a catalytic converter. The insides of the pre-cat were
damaged and had blown into the cat. It is assumed this happened because the machine was running too lean.
Figure 1: Initial State of 2007 Yamaha Phazer
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1.3 2012 CSC Team Goals
Our group began work in the 2011 fall semester with the sled in the condition described above, hoping
that we might be able to repair the sled and then modify it appropriately for the upcoming 2012 Clean
Snowmobile Challenge. However, using a “lessons learned” approach, it was clear that the Department of
Mechanical Engineering would require ample amounts of testing on a working machine before approving the
expenses of another competition. After examining the amount of work it would take to both repair the sled and
modify it for competition, it was clear this could not be done by the inexperienced team this year in time to
make the registration deadline. Therefore, the overall purpose of this project shifted to one that was more
feasible: restoring a damaged snowmobile to proper working order. The project’s key goals included the
following:

Assemble the engine, wire it properly, and adjust the control parameters to run at stock
conditions

Repair and paint the damaged cowlings.

Send the exhaust system out for repair.

Design and fabricate a fuel injector flow bench and use it to better understand how higher
contents of ethanol affect fuel injector performance.

Create proper documentation of all processes and data so that next year’s team will be well
positioned for its work on the snowmobile.
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2.0 Reassemble Sled
2.1 Rebuilding Engine
The rebuilding process of the twin cylinder 499cc engine was done with the help of the Yamaha Manual
[13] and two local mechanics, Karl Gurschick and Mark Gillman The first step was the installation of new pistons
and rings. To ensure the cylinders were smooth, a honing tool was used to give the cylinders a mirror-like finish.
A small amount of oil was also added to the cylinder to ensure proper lubrication during the piston installation.
Before putting the piston into the cylinder the piston rings were put onto the
cylinder and properly aligned. Assembly oil was applied to the rings and a ring
compressor was put around the piston and rings. The rings provide the piston
with a seal in the cylinder during combustion, so they needed to be compressed
in order to fit inside the cylinder. The compressor was aligned and the
piston/ring assembly was knocked into the cylinder, shown in Figure 2 to the left.
It is crucial that the rings are compressed and lined up properly or the rings can
Figure 2: Knocking the Piston
into Cylinder
be damaged during installation. This is a lesson our group learned first-hand. During the first attempt a ring was
damaged. The second attempt was a success. By examining the correct positions of the connecting rods to the
crankshaft, each piston was put into its corresponding cylinder. The connecting rod bearings were replaced and
the connecting rods were then fastened and torqued to the crankshaft.
The next step was to prepare the upper and lower crankcase to be connected. The mating surfaces of
both pieces were cleaned so that they were free of any old gasket. Yamaha 4 liquid gasket was applied to the
upper crankcase mating surface and the dowels were placed in their appropriate holes. The lower crankcase was
then placed on top of the upper crankcase. Following the numbering system on the bottom side of the
crankcase, bolts were oiled and threaded into the crankcase.
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The oil pump assembly was also installed using the liquid gasket. The oil
pump driven sprocket and chain was then attached to the crankshaft gear. The oil
pan was then attached to the mating surface on the upper crankcase using
thirteen bolts. After cleaning both pieces, the magneto rotor was secured to the
end of the crankshaft. The pin was attached to the magneto bolt, the bolt was
torqued, and the magneto rotor casing was attached and secured, shown in
Figure 3, to the right. The chain guide was then installed on the balancer side.
Figure 3: Attaching Magneto
Rotor Casing
This step should have been done before setting the crankshaft, so the crankshaft
gear needed to be pulled off. This was very difficult since the gear had been over tightened and broken off in the
past, due to it being a left-hand threaded bolt. Next, the chain guide was attached around the timing chain and
secured. The crankshaft gear was then put back on and the bolt was tightened.
The primary drive sheave was then attached making sure to line up the “c” on all three gears. Sandpaper
was used to clean the mating surface of the head. The head gasket was placed around the cylinders and the
head was set on top of the gasket. The head bolts were tightened in the correct sequence according to the
owner’s manual. It is important to remember to feed the timing chain through
the head gasket and head. Next, the “double dash marks” on the magneto rotor
were lined up with the stationary pointer to make sure timing was correct. The
timing chain was then hooked to the camshaft sprockets. The intake and
exhaust camshaft caps were attached after that, shown to the left in Figure 4.
The timing chain fell off when attempts were made to tighten the bolts on the
Figure 4: Attaching Intake and
Exhaust Cam Shaft Covers
intake camshaft cap. At this point we realized that we had not yet installed the
timing chain tensioner. Once this was completed, the process continued
smoothly. The drive shaft was turned to make sure the timing chain was securely set on the camshaft sprockets.
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Finally the oil filter and throttle bodies were attached. A step by step process of assembling the engine, including
all details can be found in Appendix A.
The fully assembled engine was dropped into the frame using the crane in Crosby Laboratory, shown in
Figure 5. To break in the newly assembled engine, Rotella 10W-30 oil must be used. The semi- synthetic oil,
Yamalube 0W-30 can be used once the engine in sufficiently broken in, approximately 300 miles. [13]
Figure 5: Dropping Assembled Engine into Frame
2.2 Wiring
2.2.1 Overview
The wiring of the engine was a much simpler process than the assembly. Both the Yamaha Phazer 2007
operations manual and the MicroSquirt manual were helpful resources. The Phazer manual described the
placement of all the various hoses. Through the use of diagrams, the manual shows each hose connection and
purpose. The MicroSquirt diagrams depicted each wires purpose and where it should connect. The re-wiring
process was simplified by the previous team's completed task of labeling the destination of each wire on the ECU
harness. The harness, including the MicroSquirt unit, is a detachable adapter that feeds all sensor signals as well
as electrical power directly to the MicroSquirt AMPSEAL connector. Since the stock engine control unit had been
replaced by the standalone MicroSquirt, our team needed to use diagrams from both the snowmobile and
6
MicroSquirt manuals. With both wiring diagrams in hand, the team extracted a sequence of instructions on how
to route the sensor and relay wiring.
2.2.2 New Sensors Added
A number of modifications made this year became an integral part of the re-wiring process. These
modifications include the addition and implementation of several sensors of crucial importance. A Wide Band
02 sensor was replaced and routed into the MicroSquirt system to measure the air-fuel ratio from the exhaust.
The 3-bar MAP sensor originally in place was exchanged for a 1-bar MAP sensor that would better suit the range
of internal pressures produced by the small internal combustion engine. A knock sensor was also wired into the
ECU's spare inlet helping to optimize power and fuel usage. Two EGT sensors were also purchased to monitor the
temperature of the exhaust gasses. This drastically reduces the chance of running the engine lean to the critical
point of failure which ultimately determined the end for University of Maine's 2011 CSC performance. After
completion of the re-wiring process, the value of input voltage for each sensor was measured using a voltmeter.
This assured that each sensor was drawing the appropriate amount of power from the snowmobile battery to
function correctly. The analog signal sent to the ECU from each sensor or its relay was verified as well. The final
step of re-wiring was to carefully organize each set of wires, so future teams will not have difficulty locating a
certain wire in the event of modification being made. [1 and 10]
3.0 Fix Engine Control System
3.1 Sensor Calibrations
One of the essential tasks before trying to start the engine is to ensure that MicroSquirt’s input sensors
are properly calibrated. These sensors consist of the Intake Air Temperature Sensor (AIT), the Coolant
Temperature Sensor (CLT), and the Manifold Absolute Pressure Sensor (MAP). The incorrect sensor calibration
7
could cause the engine control unit to output inaccurate values to the engine. This could damage the engine due
to incorrect firing or overheating.
The Coolant and Intake Air Temperature sensors are both calibrated using a similar method. The sensors
work by measuring the resistance across a small semi-conductor. The relationship between the resistance and
the temperature is a logarithmic function. Tunerstudio has this equation pre-programmed and only requires
three different readings. The readings measured after calibrations are listed below in Table 1. Tunerstudio
requires a bias resistor value that will act as a default value. For these sensors, this value of 2490Ω is an input
directly into the MicroSquirt unit.
The first step of the calibration is to remove the sensors completely from their housings on the
snowmobile. Next, a voltmeter that can measure resistance is attached to the sensor’s electrical leads with
alligator clips. A thermocouple is used to measure the exact temperature of a container of water. The
thermocouple and the tip of the sensor are then placed in the water, once the readings have reached steady
state the values are recorded. Heat transfer to the sensor depends partially on the material of the sensor. This
means it may take a short time for the sensor to come to equilibrium and provide accurate readings. Table 1
shows the results of the sensor calibrations.
Table 1: Results from AIT and CLT Sensor Calibration to be entered into TunerStudio
Sensor
AIT
CLT
Temp 1
o
196 F
193 oF
Resistance 1
260 Ω
280 Ω
Temp 2
Resistance 2
o
150 F
119 oF
535 Ω
878 Ω
Temp 3
o
63 F
82 oF
Resistance 3
2160 Ω
1797 Ω
The MAP sensor is used to measure the absolute pressure in the engine manifold. These readings are
sent to the engine control unit and are used to calculate air density and air mass flow rate into the engine. The
values determine the required fuel to be added into the engine. Proper calibration is necessary to run the engine
correctly. The MAP sensor is calibrated by attaching a vacuum tester to the air inlet on the sensor. While
8
applying a known vacuum pressure through the sensor a corresponding voltage reading is recorded. This voltage
reading is obtained by attaching the red lead of the voltmeter to the 5 volt input wire of the sensor and the
black lead to the ground wire. Before inducing a vacuum on the sensor, voltage readings were recorded. The
data is given below in Table 2.
Table 2: Results for MAP Sensor Vacuum Test for Calibration
Test #
1
2
3
4
Avg
Voltage 1
4.78
4.76
4.75
4.76
4.7625
Pressure 1 (in. Hg)
0
0
0
0
0
Voltage 2
3.96
3.97
3.14
3.11
3.545
Pressure 2 (in. Hg)
5
5
5
5
5
After converting to kPa, the resulting pressures can be plotted as a function of voltage. The linear
relationship is shown by the equation of the curve below. Tunerstudio prompts the user for corresponding
pressures at voltages of 0 and 5 volts. Plugging those voltages into the equation gives you the values shown in
Table 3.
Equation 1
Where:
is the pressure in kPa
is the voltage in V
Table 3: Results of Calibration of MAP Sensor for Entry in Tunerstudio
Voltage (v)
0
5
Absolute Pressure (kPa)
2.547
106.137
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3.2 MicroSquirt Firmware
3.2.1 Selecting the Firmware
Having the proper firmware installed on the MicroSquirt is a big key to having the engine run properly.
When the team started on the project, the firmware was extremely outdated and needed to be updated.
Running old firmware with new tuning software was causing the tuning files to become corrupt and ended up
freezing the MicroSquirt unit. The only way to fix this issue was to update the MicroSquirt’s firmware.
Essential to the success of getting the engine to run properly was finding the proper firmware package
that was compatible with the MicroSquirt unit and also came with the setting files for Tunerstudio. The
firmware we ultimately decided to use was actually not the latest firmware for the MicroSquirt unit. The reason
we chose an older version was due to the bugs that were still being resolved with the newer MicroSquirt
firmware. With, the newer firmware, we were not getting a response from the VR sensor that is used to read the
engines RPM. However, using the MS2-MicroSquirt BG 2.890 firmware found on diyautotune.com, we were able
to get the engine running properly with no file corruptions. [1]
3.2.2 Installing the Firmware
To install the firmware onto the MicroSquirt unit we were first required to download the files from
DIYautotune’s site. The package we used was package 041309. After the setup is run, we located where the
installation program placed the executable files. These are usually placed in a folder called Megasquirt in your
applications folder. We then located the file named gms2dl.exe, which was located in the folder MS Download
2.00. After we started the program, we were then prompted to short the B/LD jumper wire on the board. This is
wire number 15, which is a purple/black wire labeled ”bootload.” We attached an alligator clip wire to one end
10
of the ‘bootload’ wire and the other end of the clip wire to the frame of the snowmobile to short it out. Next we
followed the onscreen directions and opened the file that was downloaded from the DIYautotune package. The
file for the MS2-MicroSquirt BG 2.890 was named “Monitor_v2.890.abs.” [1]
3.3 Tunerstudio Setup
3.3.1 Initial Set-Up
Setting up Tunerstudio is an essential part to getting the ECU working properly, the program needs the
proper setting files in order to communicate with the ECU and not have any corruption issues. When the
firmware package from DIYautotune is installed, it also installs the correct setting files for the firmware versions
included. The very first step after selecting the correct settings is to go into the Fuel Set-Up tab and select the
option for General Settings. Under this tab is a setting called ECU Type, which must be selected first before
entering any other values. The unit we are using is the MicroSquirt module, so the number 2 must be entered.
[1]
3.3.2 Calibrating Sensors
After the project is created, the sensors calibration curves needed to be entered into the tuning
software. This was done under the tools pull down menu. The three that need to be done are the Throttle
position sensor (TPS), which is located under the Calibrate TPS option, and two others that are located under the
sensor calibration option, which includes the Manifold Absolute Pressure (MAP) sensor and the Barometric
Sensor. To calibrate the TPS sensor, the ECU needs to have power and be connected to the computer. To get the
closed throttle ADC count, the throttle is left at 0% and the ‘get current’ button is pressed. MicroSquirt will
automatically determine the current and enter it where necessary. Next, the throttle is held at 100% to get the
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full throttle ADC count. Similar to the previous step, the current is determined by pressing ‘get current’ and the
value is automatically inserted. Next, the MAP sensor and the Barometer sensor calibration curves are entered.
These numbers were found using a vacuum tester as described above in the section labeled Sensor Calibration.
Since the MAP sensor is based on barometric pressure, both entered values will be the same. The numbers
entered into the program are 2.5kPa for the value at 0.0 volts and 106.1kPa at 5.0 volts. [1]
3.3.3 Fuel Set-Up
3.3.3.1 General
The next step is to set the general parameters of the engine. The fuel set-up tab has multiple sub-tabs
that contain the general parameters of the engine. They are mostly constants, but some of the values can be
altered to increase engine performance.
The ‘General’ tab includes Engine Displacement, Injection Timing Delay, Injector Table Use, X-Tau usage,
the number of points for the tuning parameters, lag factors and sampling rates. The ECU type should have
already been entered to a value of 2.
The engine displacement is a known constant. The engine in the Yamaha Phazer is 499cc, which can be
converted 30.4508 cubic inches. Note the software is only accurate to the ones digit; therefore, the value is
truncated to 30.0 cubic inches.
The next value is the injection timing delay. The timing delay is used to control the delay of each squirt
from the injectors and is calculated as a percentage. The engine is quite sensitive to the number of squirts from
each injector; therefore, this value can greatly impact performance. This setting does not have a mathematical
method to determine the exact number, so the default value of 10% was used.
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Next, is the Injector Table Use information. This setting is used to determine if each bank of injectors is
controlled independently with different sets of VE and AFR tables or if each one uses the same tables. This
setting can be modified if more advanced tuning occurs, but for now it is set to a single table use to simplify the
tuning process.
The Barometric Correction is a correction based on the atmospheric barometric pressure. As a default,
this setting is read from the initial MAP reading. However, if the engine undergoes extreme altitude changes, a
separate sensor to read the barometric pressure should be installed.
The prime, ASE, WUE & Baro Tables setting is used to input a two point setting, which is a high and low
temperature setting, or a 10 entry table for the prime pulse, afterstart enrichment, and warmup enrichment.
We chose the two point option for simplicity, but if further tuning is needed, the selection for the table can be
selected.
The Input Smoothing Factors are used to control the signal noise from the various sensors on the
snowmobile. The higher the Lag factor, the less lag on the signal, meaning a number of 100 is no lag at all. The
initial values were MAP(50), RPM(50), TPS(50), LAMDA(60), CTL/IAT/Batt(50), and KNOCK(80). All the values
were left at default except for the TPS, which was increased to 80 because the lag was causing the engine to die
when the throttle was instantly pressed to 100%, indicating a slow signal.
The sampling rates are used to collect the data used to run the engine, the default value was set to 25
milliseconds and was left at this default. [1]
3.3.3.2 Idle Control
The Idle Control setting is used to control the idle of the snowmobile after start up. This is usually used
for engines that have a solenoid, a stepper, or other form of idle control. The 2007 Yamaha Phazer has an idle
13
control valve, which is controlled manually on the front of the engine. Therefore, it is not controlled by the ECU
and the setting choice is ‘none.’ To control the idle of the snowmobile, there is a screw suspended in front of the
snowmobile’s engine. To increase the idle rpm, the screw is turned clockwise, and to decrease idle rpm it is
turned counterclockwise. [1]
3.3.3.3 Spare Port Settings
The Spare Port Settings tab is used to declare the usage of optional pins from the MicroSquirt unit. The
Phazer uses one pin for the Knock Sensor. This sensor, however, is not functioning properly, and has been
disconnected. [1]
3.3.3.4 Injector Characteristics
The Injector Characteristics tab is used to control the fuel injectors. These settings are used for the
specific injectors in the snowmobile. The various settings include Injector Opening Time, Battery Voltage
Correction, PWM Current Limit, PWM Time Threshold, and Injector Time Threshold.
The Battery Voltage Correction value has default value of 0.20. This value is use to correct for Injector
Opening Time. The calculated value is 0.7 milliseconds and after correction is 1.0 millisecond
The injectors in the snowmobile are high impedance injectors; therefore, the PMW current limit must
be set to 100% and the PWM time threshold must be set to 25.4 msec. The Injector PWM period has a default
setting of 66 milliseconds and was not altered. [1]
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3.3.3.5 Injection Control
The injection control tab contains various engine and injector parameters. Under this tab there is a
selection called Required Fuel. The required fuel is the total amount of fuel needed to initiate the combustion
process in the engine. The Required Fuel setting requires the inputs of Engine displacement, Number of
Cylinders, Injector Flow Rate, and Desired Air Fuel Ratio.
The engine displacement, previously calculated in the General Fuel Set-up section, is 30.0 cubic inches.
The snowmobile engine has two cylinders.
The injector flow rate was determined from the injector flow bench test. The details are found later in
the report. The final rate is approximately 18.0lb/hr, and this was used in the setting.
The desired air-fuel ratio is 14.1 for a mixture of 10% ethanol and 90% gasoline. This number varies as
the mixture of ethanol and gasoline fluctuates.
Once these parameters are entered, the system calculates the required fuel for the snowmobile. For
the settings described above, the value is 9.10 milliseconds. Note that the system uses values from other
settings under the injection control tab.
The Control Algorithm setting, found directly under Engine Control, is determined next. This setting
provides the option to use the speed density, calculated from the MAP and the RPM readings, or use the AlphaN setting, calculated from the throttle position and the RPM to control the fuel input, or a combination of both.
After a few trials, we chose the option based on speed density.
The remaining settings are all engine constants. The squirts per engine cycle are 2, the injector staging is
“alternating,” the engine stroke is “four stroke,” the number of cylinders is 2, the injector port type is “throttle
body,” and the number of injectors is 2. These values were all found using the manual and engine knowledge.
[1]
15
3.3.3.6 Rev Limiter
The Rev Limiter is used to control the engine at high RPMs. This is used to protect the engine from
operating outside of its safety ratings. There are two choices for the rev limiter algorithm, one being a spark
retard and the other a fuel cut. The simplest to control is a fuel cut algorithm, which uses specific limits to
determine when to stop the fuel flow to the engine. The Lower Rev Limit of 11250RPM and the Upper Rev Limit
of 11500RPM were listed in the Yamaha Manual and used in the ECU. [1]
3.3.3.7 After-start Enrichment
The After-Start Enrichment (ASE) setting controls the amount of extra fuel added when the engine
initially starts. The setting provides the option to enable ASE when the engine does a hot start. The engine in the
Yamaha Phazer does not need the extra fuel after a hot start; therefore, it is not enabled. The other settings
listed are set to the factory defaults of ASE cold percent 45%, ASE hot percent 25%, ASE cold count 350 cycles,
and ASE hot count 150 cycles. These numbers are relatively small, and the after-start enrichment generally only
lasts a few seconds. If the engine tries to start but dies right away, these numbers will need to be adjusted. [1]
3.3.3.8 Accel Enrichment Config
The Accel Enrichment tab is used to control the acceleration parameters. The setting is called the Low
RPM Threshold, which is the RPM value where the acceleration wizard dictates engine functions. This value
must be above the idle RPM or else the engine will run using acceleration settings when the snowmobile should
be running at a steady idle. If this number is too low, the engine will fluctuate through a wide range of RPM with
no user input.
16
The High RPM is a similar setting. Once the RPM reaches this value, the acceleration wizard is no longer
used, and the engine maintains the original settings. Although the acceleration wizard is not active, the engine
can still increase RPM, just not as rapidly. [1]
3.3.3.9 Other Fuel Settings
The Other Fuel Settings tab has multiple random settings. The first section of this tab is the Engine Start
Up, which consists of settings for Max Cranking RPM and TPS for Flood Clear Mode. The Max Cranking RPM is
the RPM when the starter motor will initiate the turning of the engine. This number was increased from the
stock value to 550RPM to achieve an easier start up. However, if this number is increased too much, it will cause
the engine to spin too fast for the variable reluctance sensor to read the RPM signal, causing the engine to not
be able to fire. Flood Clear Mode is used to correct an engine flood situation. This number is usually set to or
near wide open throttle, in order to remove excess fuel from the cylinders. This mode is only active when there
is extremely low rpm when the throttle is wide open.
The next set of settings is for the VE table adjustment. The first setting provides the option of
controlling the volumetric efficiency tables with either the MAP sensor or a barometer. Since there is no
barometer on the snowmobile, ‘Use Map Only’ is chosen.
Next, is the AFR Table Fuel Calc Usage setting. This provides the option of either combining the VE/AFR
table information with the oxygen sensor to calculated fuel usage or use the information separately. We have a
wideband O2 sensor installed, so the setting to use separate VE & AFR table w/ WB EGO is selected. This will
separate the tables and use the readings from our wideband sensor to calculate the fuel usage. With this
selection, the AFR value is needed as an input. As previously mentioned, the air fuel ratio for 10% ethanol is
14.1.
17
The next section is Two-Point Prime. This section is used to prime the engine when it is initially started.
These values are simply added to the normal pulse width during start up. The input required is two points, which
creates a linear curve based on temperature. The values that worked the best for priming were; a Prime Pulse
Cold PW of 6.0 milliseconds, a Prime Pulse Hot PW of 1.0 millisecond, and a Prime delay of 1.0 millisecond. The
remaining settings were not altered. [1]
3.3.3.10 Two-Point Barometric Correction
The 2-point Barometric correction is used to correct the engine based on the barometric pressure. These
numbers are given by MicroSquirt are not to be altered. They are at total vacuum 147.0% and Rate of -47%. [1]
3.3.3.11 Flex Fuel
The flex fuel sensor is used to measure the ethanol to gasoline ratio of the fuel as well as the fuel
temperature. The sensor sends a signal to the ECU to optimize the ignition timing as well as the amount of fuel
injection. The settings listed in the flex fuel settings tab are all default values, since most flex fuel sensors have
the same output signals, making them universal with other vehicles. The default numbers are

the Frequency (low), which is 50Hz

the Fuel correction (low), which is 100%

the Timing Correction (low), which is 0.0 degrees

the Frequency (high), which is 150Hz

the Fuel correction (high), which is 159%

the Timing Correction (high), which is -13.0 degrees.
When trying to initially tune the snowmobile and achieve a steady idle, the flex fuel sensor was disabled
so it would not compensate the engine for the ethanol percentage and input different values for the injection
18
timing and the fuel injection. If this was not done, the tuned values would have been incorrect, and the tuning
process would have been more difficult. [1]
3.3.3.12 EGO Control
The EGO control uses an O2 sensor to read the air fuel ratio and output a signal back to the ECU so it can
compensate with any discrepancy. It adjusts fuel flow rate until the value matches the input value for AFR (14.1
for 10% ethanol). This setting was also disabled when the engine was being initially tuned. If this was enabled,
the compensation of the EGO would make it nearly impossible to tune the engine to run properly. This setting
can be enabled once the engine runs perfect. [1]
3.3.3.13 Automatic Mixture Control
The Automatic Mixture Control is used when the EGO controller is enabled. This setting alters the VE
table to change the mixture of the fuel to compensate for the readings from the O2 sensor. Until the EGO sensor
works properly and the engine is running correctly this setting cannot be changed. [1]
3.3.3.14 Alpha-N Blending
This setting is enabled when the control algorithm setting in the Injection control tab is changed from
speed density to either Blend SD/Alpha-N’ or ‘Pure Alpha-N’. The settings in this tab are to control when the
controller switches from the Alpha-N to the Speed density. The difference is explained above in the Injection
control section. [1]
19
3.3.3.15 MAP vs. MAF Usage
This tab is to set up a Mass Flow Sensor (MAF). Mass Flow Sensors are used to measure the flow of air
through the manifold. Snowmobiles are not equipped stock with a MAF sensor and do not need them to
operate. This setting is mostly used for cars and can be ignored unless a MAF sensor is installed. [1]
3.3.4 Ignition Set-Up
The Ignition settings tab consists of more engine constants. These numbers are what control the
engine’s ignition events. Most of these settings were taken from the previous team’s tunes as well as from
engine research. [1]
3.3.4.1 Base Ignition Settings
The Base Ignition tab is used to control the spark output. The first setting is the Trigger Offset, which is
the advance before or after top dead center when the engine receives a signal from the engine’s variable
reluctor or hall sensor. This is used to sense what position the engine is in, which determines when the spark
plugs are fired. To calculate this number a timing gun is used to measure the timing of the wheel. We measured
-351.50 degrees.
The next setting is the number of Skip Pulses. This number is the amount of ignition pulses during startup that the MicroSquirt unit will ignore before it uses the signal from the VR sensor to calculate advanced
ignition signals. This number is generally a small value since the engine only needs a few cycles to get up to
speed. We used three skip pulses. If this number is too low, it will receive the advanced signals too fast and will
20
not be able to start correctly. If the number is too large, the engine will be running off of a start-up pulse and
may damage the engine.
The next setting is the Predictor Algorithm. This setting is used to predict the time it will take before the
next top dead center event. Because we have two separate tachometer inputs, the VR sensor and the Cam
Position Sensor, we are able to use a simple algorithm to predict this event. The setting called ‘last interval’ uses
these two sensors and takes the previous timing to predict the next one.
The next setting is the Tachometer Signal Masking. This setting is used to eliminate signal noise from
the tachometer. The default values are a Time Mask of 0.2 milliseconds and a Percentage Mask of 10%. If extra
noise is noticed, these numbers can be increased.
The next settings are for the Next-Pulse Tolerances for cranking, after-start, and normal running. These
percentages are the tolerances of time where the next pulse is not considered a ‘true’ pulse, but as a ‘false
trigger’. These tolerances are also defaults from the MicroSquirt manual; Cranking 70%, After-Start 80%, and
Normal Running 40%.
The next settings are to control the signals to be received and emitted to the spark plugs for proper
engine firing. In order to properly adjust these settings correctly, one must know the shape of the input signal.
For the snowmobile, it is a square wave that captures the ignition at the rising edge of the signal. The Cranking
Trigger will be calculated from the previous pulse times, resulting in smoother spark timing.
Next is the Coil Charging Scheme, used to specify how the coils will be charged. The coils in the Phazer
are standard coils. A standard charge setting fires a spark when the current to the coil is interrupted. The spark
output is the signal the ECU sends to activate the spark plugs. The current was tested when the engine was off. If
there is a current, then the signal must be inverted. After doing this test, it was concluded that the snowmobile
needed to run the ‘Going High (Inverted)’ setting. [1]
21
3.3.4.2 Dwell Settings
The Dwell is the length of time the coil charges before releasing a spark. This number has to be carefully
calculated. If the coil doesn’t charge long enough, it will not give out a powerful enough spark for the engine to
fire properly. Alternatively, if the coil charges too long, it will still emit a substantial spark but will overheat due
to the extra charge and possibly destroy the coils. The dwell is calculated using a calculator provided on the
mega manual website. The first setting needed is the Maximum Dwell Duration, which was calculated out to be
2.5 milliseconds. The Maximum Spark Duration was calculated as 0.5 milliseconds. The Acceleration
Compensation is the amount of time added to the duration of the spark when the acceleration enrichment is
activated. This number is determined using a guess and check method and tuned according to the performance
of the coils when under acceleration conditions.
Next are the Battery Voltage Compensations. These settings are used to compensate the dwell spark
when the battery is below or above optimal voltages. This is needed because the voltage of the battery will vary
according to the voltage of the coil. These settings are to be kept at their default settings, found on the mega
manual website. [1]
3.3.4.3 Advanced Ignition Options
The Advanced Ignition Options are used to set the trigger wheel settings. The trigger wheel is designed
to sense the position of the engine. In most vehicles, the trigger wheel is made up of a wheel with a certain
amount of teeth with one tooth completely missing. The sensor reads the tooth signal and sends it to the ECU
when the missing tooth goes by the sensor. In the case of the snowmobile, the trigger wheel is a unique design
and has a 12 tooth design of coils surrounding the shaft. When these coils pass by the sensor, it reads each coil
22
separately. With no missing tooth, it is impossible to get the position of the engine correctly with just this
system. Therefore, the snowmobile uses a second position sensor in the cam shaft. Both sensors must be
functioning together to determine an accurate engine position. The design of the wheel has large gaps between
each tooth; therefore, the parameters are set as if there are 12 teeth with a missing tooth in between each
tooth. So, the setting for Trigger Wheel Teeth is 12, Missing Teeth is 0, Skip Teeth is 12 and Delay Teeth is 0.
Any other settings will cause the engine to not properly pick up the RPM and not fire. The Dual Spark option
must be selected in order for the second sensor to work. These settings are to be set to ‘falling Cam Sync with
Tach or Wheel’ with an offset for output to be at 180.0 degrees. This indicates the second input is sensed off the
Cam shaft and the sensors read 180 degrees apart from each other.
The next ignition setting is the IAT-base Spark Retard Limiting options. These options are set to hold
the spark when the temperature of the air intake is significantly high. Since this temperature is read from the air
box on a snowmobile, this value is generally going to be quite low with little risk of being too high. The default
values of 800 and 1500 were used. Also there is no need for a signal delay, so both delays were set to zero. If
there was a delay, the timing would be offset and cause the engine to have improper timing. [1]
3.4 Tuning MicroSquirt
3.4.1. Overview
After all the engine constants were set, the engine is almost ready to be fired. The following tuning
parameters must be within range in order for the engine to run. The first step is to get the VE table and the AFR
tables in the correct range of the correct value so they can be tuned after the engine idles correctly. [1]
23
3.4.2 VE Table
Although Tunerstudio is able to generate a VE table based on the inherent characteristics of the
snowmobiles engine, initial attempts using the generated VE table generator resulted in numbers that did not
correlate with the nominal profile trends seen in almost every other VE table. The table was then created by
hand, using previous years VE tunes as well as knowledge acquired from the manual about the general VE
profiles. After initial start-up attempts appeared too rich on the O2 sensor readout, the numbers where adjusted
accordingly to achieve the correct air fuel ratio. With an increase in the volumetric efficiency, the increase in fuel
caused the engine to run rich. Likewise, with a decrease in VE the snowmobile was running too lean. The
Volumetric Efficiency cannot be changed until the snowmobile is at optimal running temperature. This is due to
the after-start enrichments as well as the warm-up wizard adding more fuel. The current VE table is shown
below as Figure 6, but there is always room for improvement on the VE table. [1]
Figure 6: Current VE Table
24
3.4.3 AFR Table
The AFR table on the current tune of the snowmobile is not ideal. Since the EGO sensor is disabled, the
AFR table is not actually being used to control the engine. The table shown in Figure 7 is what is assumed to be
in range of the correct values, but these values must be tuned once the EGO is enabled. [1]
Figure 7: Current AFR Table
3.4.4 Warm-up Wizard
The warm-up wizard is used to assist the engine in reaching optimal running temperature by adding
more fuel to the engine. The optimal running temperature for the 2007 Phazer is between 185-200 degrees
Fahrenheit, so the enrichment should end around that temperature. The enrichment starts at 180% enrichment
at -40.0 and -20.0 degrees Fahrenheit. This means it is adding 180% of the required fuel needed to run the
engine. The extra fuel causes the engine to run very rich and allows the engine to start and run at low
temperatures with ease. As temperature increases the enrichment is slowly tapered down until it reaches the
optimal running temperature where final enrichment is 100%. The current tuning of the Warm-up wizard works
for the snowmobile using 10% ethanol and is predicted to continue with increase amounts of ethanol. However,
if the engine is running at a very high RPM while warming up, the values may have to be decrease, or
25
alternatively if the engine is running at a low RPM, the numbers may have to be increased. Also, on the WarmUp wizard the Cranking Pulse widths can be tuned. The input values are for pulse widths at temperatures of 40.0 degrees and 160.0 degrees Fahrenheit. For the Phazer, these values were found to be 4.8 milliseconds at 40.0 degrees Fahrenheit and 1.0 millisecond at 160.0 degrees Fahrenheit. Again, this may need to be altered
with an increase in ethanol content. The Flood Clear Threshold can also be tuned on this screen, but was left
alone because this number was already set from the Other Fuel Settings tab and is rarely used on a snowmobile.
[1]
3.4.5 Acceleration Wizard
The acceleration wizard is used to control the acceleration of the engine based on either the Manifold
Absolute Pressure (MAP) sensor or the Throttle Position Sensor (TPS). This wizard is used to increase pulse
width to the injectors to add more fuel when the engine is accelerating. The Yamaha engine is a four stroke with
only two cylinders. The two cylinders works at different times, causing the pressure to pulsate with the engine
cycles, causing an unsteady signal to the MAP sensor. A fuel filter was added before the MAP sensor, but was
not able to provide a constant signal to determine the acceleration solely on the MAP sensor readings. The
throttle position sensor will always give correct values of the opening of the throttle body. This allows us to use
solely the TPS readings when tuning the acceleration of the engine.
The first setting is the MAPdot threshold, which can be ignored since we are no longer looking at the
MAP sensor readings. All the other settings must be set to acceptable ranges in order to get a steady
acceleration. The values that are entered in all of the other sections are all default values from the tuning
document. The only values altered were the values found on the graph. The graph adds pulse width based on
the percent increase of the throttle position. When the throttle was suddenly increased from 0 to 100, the
engine was not responding properly. This was caused by adding too much fuel. Therefore, the values were all
26
decreased so the pulse widths were not increased as much. The values that allowed for a good acceleration
were a linear correlation starting at 100%/sec adding 2.0 milliseconds to the pulse width to 2980%/sec adding
8.3 millisecond. These numbers were found using a guess and check method and can be further tuned for better
acceleration. The range we used from 100-2980%/sec is much larger than needed but was used to make sure a
rapid acceleration from 0-100 would not extend out of the graphs regions. [1]
3.4.6 Cold Advance
The Cold Advance setting is used to add more ignition spark when the engine is colder than normal. This
number is essential to the snowmobile application because most start-up will fall under this criterion. The
settings are based on the coolant temperatures and should only be used for extremely low temperatures. The
temperature range that is needed is approximately -40 to 80 degrees Fahrenheit. After 80 degrees there should
be no added offset. We were not able to tune this because it is hard to reach these temperatures on the
snowmobile without testing outside in winter conditions. Due to these limitations, the default values were kept
in place and need to be tuned. [1]
3.4.7 IAT-Based Fuel Correction/ IAT-Based Timing Retard
The IAT based fuel correction and timing retard is mostly used for car applications when the intake air
temperatures are very high. With the snowmobile, the air intake temperature is low enough that it will never
reach the values used for the corrections. This means no matter what values are in these graphs, they will have
no effect on the way the engine runs and therefore are not altered. [1]
27
3.5 MegaLog Viewer
When running tuning tests, it is helpful to use the MegaLog Viewer. User defined selections can be
tracked over time for a better understanding of how the engine is running, and which parameters could be off.
An example of this information in graphical format is shown below in Figure 8. This data can also be excessed in
a spreadsheet format. All of our tunes have been saved by date for future reference.
Figure 8: MegaLog Viewer
4.0 Ethanol
4.1 Theory
Going along with this project's overall purpose, to leave the following team in a position to progress
towards having a competitive snowmobile, the following section provides suggestions to increase the
snowmobile's capability to run on ethanol based fuel. In order to be competitive in the CSC, the snowmobile will
need to be functional when run with a higher ethanol content fuel. Much of the theory backing the adaptation
of a stock snowmobile to run on ethanol is based on compensating for the chemical properties inherent to
ethanol fuels and the issues this causes in an engine designed for octane.
28
The first issue with ethanol fuel is water contamination. [3] One of the chemical properties of ethanol is
its ability to evaporate water. When ethanol is used in higher concentrations and atmospheric moisture enters
the fuel system, a typical occurrence, the ethanol will separate from the water leaving a pool of water in the fuel
system. The water will move through the fuel injection system. Repeated instances of this can and will cause
serious damage to the engine. Standard 87 Octane fuel, which is considered an E10 blend, does not have a high
enough content of ethanol to initiate this absorption and therefore will not create this problem.
Ethanol is also known to have a higher rate of corrosion in both the rubber gaskets and the aluminum
engine casing. Ethanol can also deteriorate the inside of the fuel tank leaving sediment in the fuel and
eventually in the motor, which can damage the engine. [3] The latter of these problems has already been
quelled two years prior with the addition of an aftermarket fuel tank tested to withstand the effects of carrying
ethanol. Each of these properties can be dealt with by improving the quality of gaskets, disconnects, o-rings, and
other components used to seal the fuel.
By far the most important alterations required to operate on ethanol are within the ECU. A new engine
tune conforming to the fuel properties of ethanol will need to be developed. The first ECU adjustment needed
to function on ethanol will be a decrease in AFR values. After increasing the content of ethanol in the fuel, the
engine will begin to run lean on all capacities: idle through WOT [3]. The energy density of ethanol is lower than
that of octane. As such, more fuel must be pumped through the injectors to counterbalance the loss in energy
density. When a higher concentration of ethanol is used, and more fuel is required and burned, the engine will
be forced to consistently run at higher temperatures than it was designed for. When the engine is run at an
elevated temperature and a large number of cycles, the metal of the engine will begin to show signs of fatigue. If
the engine continues running under these conditions, the fatigue will ultimately turn into failure. Use of ethanol
fuels will also produce a detrimental increase in EGT and can cause throttle plate ware.
29
The next measure to prepare the ECU and the snowmobile for ethanol will be advancing the ignition
timing and determining the necessary timing correction needed for the SAE specified fuel range for competition.
Ethanol is much harder to burn and therefore takes a longer period of time to vaporize. This being the case, the
ignition timing may be advanced to compensate for the increase in the time needed for fuel vaporization. The
autoignition temperature of Ethanol is approximately 689 ºF, whereas the autoignition temperature of standard
gasoline is 475 ºF. [12] Other engines that have been modified for ethanol fuel use pre-heaters to bring the fuel
to a higher temperature prior to combustion, making it more ready to burn. This task can also be accomplished
by switching to a spark plug with a higher thermal conductivity value, also known as a hotter spark plug. [11] In
many cases the ignition timing, measured in °BTDC (degrees before top dead center), has been doubled in order
to compensate for the increase in vaporization time for ethanol. Another issue that ethanol fuels bring is the
significant increase in fuel usage. Ethanol blends require more fuel to achieve the same power output as
gasoline. [12] This must be overcome to use ethanol. Additionally, cold starts can be problematic when running
ethanol. The cold-start difficulties also correspond to ethanol's drawback of having a higher autoignition
temperature. Fuel pre-heating, interchanging spark plugs, and correlating the ECU's warm up enrichment inputs
to the difference of fuel are possible alterations that could improve the snowmobile's cold-start ability, a main
scoring criteria in the CSC each year.
4.2 Testing for Ethanol Content
When working with a fuel mixture, it is important to know the exact percentage of ethanol and gasoline.
This is easily determined with the following procedure. [5]
1. Using a pipette, put 50 mL of the fuel in a 100 mL graduated cylinder.
2. Similarly, add 50 mL of water.
3. Secure the fluid with a stopper and shake vigorously for about 15 seconds so the fluids mix thoroughly.
4. Loosen stopper to release any pressure.
5. Reinsert the stopper and allow the fluids to separate for at least 15 minutes.
30
6. Determine the volume of the top layer, using the markings on the graduated cylinder (
). This is the
hydrocarbon layer.
7. Calculate the concentrations.
a.
b.
5.0 Cowling Repair
5.1 Initial State of 2011 Team’s Cowlings
The previous team designed and fabricated custom cowlings for the 2007 Yamaha Phazer, three pieces
that individually attached to the machine. A side piece covers the clutch, one on the other side covers the
radiator, and a top piece covers the engine. The inside of the front cowling and the clutch side was covered with
sound deadening material and heat resistant material. The cowling covering the radiator had only heat resistant
material on its inside. There had been some damages to the cowlings from the failure at the previous
competition. Each cowling was at a different stage of repair. Some soft spots had been fiber glassed and smaller
defects covered with Bondo. The exact process they used and how to continue was uncertain, due to lack of
written communication.
5.2 Repair and Painting Process
Before the outside cosmetic damages were accessed, the inside of the clutch cover was addressed. The
existing sound deadening material had been damaged by fiber glass resin. It was removed and new material was
applied. The material used is self-adhesive so it was put on similar to a sticker.
31
The first step in correcting the outer damages was to start
sanding to gain a better understanding of the condition of each of the
individual cowlings. 100 grit sandpaper was used for this stage. Some
dents and weak spots were noticed and Bondo was used to attempt to
repair these. The top cowling at this stage is shown to the right in
Figure 9. The Bondo was not enough to repair all of the weaknesses.
Fiberglass was then applied to these problem areas and allowed to
Figure 9: Cowling after Initial Sanding and
Coat of Bondo
harden overnight. The next day the fiber glass was sanded (with 40 grit sandpaper) to a smooth enough finish to
be covered with Bondo.
A coat of white primer was then applied in two coats. Since the cowlings were varying in color, this stage
allowed all of the small imperfections to be visible. Many of the flaws were likely able to be fixed using Bondo.
Three stages of Bondo were applied with sanding in between. The sanding began with 80 grit followed by 100
grit then 200 grit each time. The final sanding was finished with 400 grit sandpaper. The cowlings were deemed
ready for the paint process at this point. The sealer was mixed with activator according to the labels on the cans
and applied in two coats with a spray gun. This will allow a good base for a consistent white color. It was allowed
to dry for about an hour. Next, after being mixed with activator according
to package instructions, two wet coats of the white base paint were
applied. The side cowlings at the stage are shown in Figure 10 to the left.
The cowlings were again allowed to dry for about an hour. The front
cowling was then taped to create the two stripes that would become
Figure 10: Cowlings after White Base Coat
black. Everything was covered so no black overspray would hit any of the
fresh white paint. The black paint was then applied in two coats and allowed to dry for an hour. The tape was
removed for the final step. Clear coat was sprayed over all three cowlings to give a shiny finish. The clear was
applied in three coats. The pieces were allowed to set over night. The next morning a few finishing details were
32
applied. Blue pin stripe stickers were used to cover the edge between the black and white paint. The two side
cowlings were covered and taped to only reveal the wire screens. Black spray paint was used to cover these.
Self-adhesive chrome door trim was molded to cover the head light opening and the top cowling edges. The
cowlings were then attached to the snowmobile using existing brackets, shown in Figure 11.
Figure 11: Finished Cowlings Mounted to Snowmobile
6.0 Fuel Injectors
6.1 Determination of Fuel Pump Pressure
The fuel used at competition is an ethanol-gasoline mixture. For the 2012 competition the range is
between E10 and E39. To achieve the same energy per gallon of fuel the pressure of the fuel pump must be
adjusted. The pressure is related to the energy content based on Equation 2 below.
Equation
2
where:
is the energy per gallon of ethanol-gasoline mixture in Btu/gal
is the energy per gallon of gasoline in Btu/gal
is the pressure for ethanol-gasoline mixture in psi
is the pressure for gasoline in psi
33
The standard energy content for gasoline is 114,000 Btu/gal for a pressure of 43.5 psi. These values
were used in Equation 1 as Eg and Pg, respectively.
The energy of the ethanol-gasoline mixture is determined using the percentage ratios, based on total
gasoline having an energy content of 114,000 Btu/hr and E100 (100% ethanol) with 76,100 Btu/hr. [4] The
method for combining is given in Equation 3.
Equation 3
where:
is the percentage of gasoline
is the percentage of ethanol
Table 4 below displays various mixtures as well as the high (E39) and low (E10) limits for the
competition. The middle range was also determined (E24.5). According the tabulated values below, the fuel
pump should be set to a pressure of 51.56 psi to achieve the best results at competition.
Table 4: Desired Fuel Pump Pressure for Various Ethanol-Gasoline Mixtures
Fuel Type
Gasoline
E100
E85
E60
E50
E39
E10
E24.5
Gasoline
Concentration
100%
0%
15%
40%
50%
61%
90%
75.5%
Ethanol
Concentration
0%
100%
85%
60%
50%
39%
10%
24.5%
34
Energy
(Btu/gal)
114,000
76,100
81,785
91,260
95,050
99,219
110,210
104,715
Pump Pressure (psi)
43.50
97.62
84.52
67.88
62.57
57.43
46.54
51.56
6.2 Baseline Fuel Flow at Diesel Fuels
In order to have a comparison for the fuel
injector flow tests that were to be run on our own fuel
injector flow bench, the snowmobile’s fuel injectors
were flow tested professionally. This baseline test was
run using an ANSU injector flow bench at Diesel Fuel
Systems in Bangor, ME. Figure 12 shows a picture of
the ANSU flow bench used for the test. This experience
Figure 12: ANSU Flow Bench at Diesel Fuel Systems
provided valuable knowledge and contacts to aid in the fabrication of our own apparatus. The machine used to
test the injectors had a setting to vary the pressure at the fuel rail. For our test, the pressure was set to 43 psi,
the factory fuel rail pressure for a 2007 Yamaha Phazer. The machine also had multiple settings that varied the
injector pulse-width and engine rpm simulation or duty cycle. The injector pulse-width is simply the amount of
time the injector is on or open, allowing fuel to pass through. The injector duty cycle is the percentage of time
the injector is open compared to the total time of one revolution of the engine. The Injector Duty Cycle is a
function of Injector pulse-width and engine rotations per minute (rpm). [6] The calculation for injector duty
cycle is described below.
Equation 4
Where:
is the injector duty cycle as a percentage
is the injector pulse-width in units of milliseconds
35
Each one of the test trials were run for 30 seconds at a fuel rail pressure of 43 psi. Data from the trials
are shown in Table 5. The plot is below in Figure 13.
Table 5: Injector Flow Rate and Test Parameters
Injector Pulsewidth (ms)
3
6
12
3
6
12
Engine rpm
2500
2500
2500
5000
5000
5000
Injector Duty
Cycle (%)
6.25
12.5
25
12.5
25
50
Flow Rate
(mL/30 s)
15
24.5
44
27.5
48.5
88.75
Figure 13: Flow Rate as a function of Injector Pulse Width
36
Flow Rate
(mL/min)
30
49
88
55
97
177.5
Flow Rate
(lb/hr)
2.712791251
4.430892376
7.957521002
4.973450626
8.771358377
16.05068157
6.3 Custom Flow Bench
6.3.1 Concept
As the Mechanical Laboratory portion of the senior design class, the CSC 2012 Team designed and
fabricated a fuel injector flow bench. The flow bench provides a rate of fuel sent to the engine by the injectors.
This value is critical in properly setting the engine controls. The rate is dependent on the pressure set by the fuel
pump and the fuel injector pulse width. To convert the engine to run with higher contents of ethanol, the
pressure must be increased due to higher fuel density and lower energy produced per unit volume (as explained
previously). The injectors may not be able to perform correctly under pressures higher than at stock settings.
The injector pulses open and close to deliver small amounts of fuel to the engine during each pulse. The pulse
width defines the time the injector is open and is a key input in the engine control unit.
The schematic of the experimental set up is depicted in Figure 14. The fuel tank, filter, pump, and
regulator are all mounted on the existing dynamometer cart. The line is then connected to a pressure gage that
can connect to the apparatus containing the fuel injectors. These injectors will sit directly above the graduated
cylinders used for measuring.
Figure 14: Concept Sketch of Fuel Injector Flow Bench
37
6.3.2 Fabrication
The graduated cylinders will be housed on a stainless steel base, shown in Figure 15 below. This base
will also hold the injectors during testing. Each piece is fabricated out of 16 gauge stainless steel. It was cut using
the sheer in AMC building. Pieces needing to be bent were also completed using equipment in the AMC building.
A dimensional drawing for each piece can be found in Appendix C. There was an existing bracket holding a fuel
pump, and regulator on the cart. A similar piece was fabricated out 1” square steel tubing, with our fuel pump
and fuel regulator mounted to it. This piece is removable and is attached with the existing hardware on the cart.
This piece is shown in Figure 16. A new tank for mineral spirits, the injector test fluid, was also attached to the
cart. The tank is mounted with a bracket made of 1” square steel tubing shown in Figure 17.
Figure 15: Fuel Injector
Housing
Figure 16: Fuel Pump and Regulator
Figure 17: Mineral Spirits Fuel Cell
6.3.3 Flow Bench Wiring
There was already a switch providing power to the bench included on the control panel. We needed to
distribute this power to MicroSquirt, the fuel injectors, and the fuel pump. Since an existing fuel pump was
removed and replaced, as described above, the existing wiring on the cart was used. The third switch on the
control panel powers the fuel pump. The fifth switch sends power to the MicroSquirt controller and to the
injectors on the fuel rail. From MicroSquirt, pins 9 and 10 each connect to an individual fuel injector. These wires
send a pulse signal to the injectors based on the test mode in the MicroSquirt program. [1] To protect the
38
circuit, fuses were added, as shown in the wiring diagram in Figure 18 below. Ground wires were connected
from the MicroSquirt unit and the fuel pump to the frame of the cart.
Figure 18: Fuel Injector Flow Bench Wiring Diagram
6.3.4. Testing
6.3.4.1 Theory
The maximum volume of fuel sent to a properly working engine is based on the engine output
(horsepower), the specific fuel consumption, and the maximum duty cycle. [2] The relationship is shown in
Equation 1 below.
Equation 5
39
The flow rate is in pounds per hour. The maximum engine output is 80 horsepower for the 2007 Yamaha
Phazer. The specific fuel consumption for this type of engine is 0.55 lb/hp/hr. For tuning purposes, the maximum
duty cycle is 80%. [2] Combining these values gives the maximum flow rate shown below in Equation 6.
Equation 6
The optimal flow rate for gasoline at stock conditions is 35.2 lb/hr.
6.3.4.2 Testing Procedure
The injectors are pressed into the adaptors and the electrical connectors are attached to the injectors. A
graduated cylinder is placed under each injector to catch the mineral spirits test fluid after it exits the injector.
Mineral spirits is added to the 1 gallon fuel cell. The empty graduated cylinders are placed on the scale and a
weight is recorded.
The main power disconnect is switched to the “on” position and the ignition key is turned on. The fuel
pump is turned on by simply flipping the switch on the control panel labeled “fuel pump”. The red light above
the switch is on indicating there is power at the switch. The lines leading from the fuel cell to the injectors are
now pressurized. A computer with TunerStudio software is attached to the auxiliary hook-up on the MicroSquirt
wiring harness. The program is opened using the computer. The MicroSquirt switch on the control panel is
flipped to the on position. This sends power to the MicroSquirt engine controller and also to the injectors
themselves. The gauges on TunerStudio are now interactive. The Tools menu is clicked and Injector Test Mode is
selected. A new window is opened. On the drop-down menu, “Test Mode” is selected and the desired
parameters are set. The pulse width is set to range from 5ms to 50ms in steps of 5ms. The injector off time is set
to a value such that the sum of the pulse width and off -time is equal to 66ms. This constant period of 66ms is a
40
property of high impedance injectors. The number of injector squirts is set to 250 to ensure the test fluid does
not exceed the capacity of the 100mL graduated cylinder. On the bottom of the window the button labeled
“Burn” is selected to save these parameters. On the drop down menu, “Repeat Test” is selected in order to
begin the test.
After the injectors have gone through the desired cycle and the Test Mode has stopped, the graduated
cylinders are removed and set on a level surface in order to get a volume reading. The graduated cylinders
containing the test fluid placed are placed on a scale to get a mass reading. This value is subtracted from the
empty cylinder weight and multiplied by the density of the test fluid to calculate a volume. The second volume
reading is averaged with the initial reading directly from the cylinder. The cylinders are emptied into the fuel cell
and placed back under the injectors. A new pulse width is entered into the Injector Test Mode window, “Burn” is
selected to save these parameters and “Repeat Test” is selected to run a new test. The remaining trials are
repeated in the same manner described above until all desired pulse widths have been tested.
6.3.4.3 Data Analysis
As mentioned previously, high impedance injectors, the period is a constant 66ms. The open time is the
set pulse width and the close time varies to achieve the specified period. Therefore, the trial time is only a
function the number of squirts as shown below.
Equation 7
Where:
is trial time in seconds
is the period (open time + close time), here 66ms
is the set number is squirts
The unit conversion values are shown below in Table 6, followed by the trial data in Table 7.
41
Table 6: Unit Conversion Values
Density of Mineral Spirits [10]
6.531
lb/gal
Weight Conversion
2.2046
lb/kg
Volume Conversion
0.0002642 gal/mL
Table 7: Trial Data for 250 Squirts
Pulse width
(ms)
5
Close
Time
(ms)
61
Trial
Time
(s)
16.5
Trial
Time
(hr)
0.00458
A
(mL)
6
B
(mL)
6
Sum
(mL)
12
Volume
(gal)
0.0032
Weight
(lb)
0.0207
Measured
Mass
(kg)
0.009
Measured
Weight
(kg)
0.0198
Average
Weight
(lb)
0.0203
Flow
rate
(lb/hr)
4.423
10
56
16.5
0.00458
13
13
26
0.0069
0.0449
0.019
0.0419
0.0434
9.464
15
51
16.5
0.00458
19.5
20
39.5
0.0104
0.0682
0.029
0.0639
0.0660
14.410
20
46
16.5
0.00458
26
26
52
0.0137
0.0897
0.039
0.0860
0.0879
19.168
25
41
16.5
0.00458
32
32
64
0.0169
0.1104
0.048
0.1058
0.1081
23.591
30
36
16.5
0.00458
39
39.5
78.5
0.0207
0.1355
0.06
0.1323
0.1339
29.207
35
31
16.5
0.00458
46
46
92
0.0243
0.1587
0.071
0.1565
0.1576
34.393
40
26
16.5
0.00458
52
52
104
0.0275
0.1795
0.081
0.1786
0.1790
39.057
Figure 19: Flow Rate as a Function of Pulse Width
42
The data was plotted and fitted with a linear curve. The equation of this line is used to determine the
maximum pulse width. This is shown below in Equation 8.
Equation 8
During the test, the injectors simply did not function past 40 milliseconds. Increasing the pulse width
beyond 40ms resulted in the injectors being stuck open. This means there was zero off time, a 100% duty cycle.
Since injectors are sized based on maximum pulse width, this confirms Yamaha’s choice to use these particular
injectors for stock conditions.
As stated previously, with higher contents of ethanol, more fuel is required to achieve the same
horsepower. Therefore, it can be assumed the pulse width will need to be even higher than tested here to
achieve peak performance of the snowmobile when it is burning ethanol. Since the injectors do not function in
this range, the idea of adding another injector should be seriously considered.
43
7.0 Exhaust Systems
7.1 Stock Exhaust
The stock exhaust system, shown in Figure 20 below, is essentially a straight pipe attached to a muffler.
It runs parallel to the track of the sled and is attached under the seat. There is a heat shield covering the
manifold, protecting the gas tank at the start of the exhaust. As shown in the picture, the oxygen sensor is
attached into the pipe before the muffler. A
digital readout is connected and wired near the
top of the engine. This sensor helps to reduce
emissions. It senses the amount of oxygen in the
exhaust air and sends that information to the
ECU. The ECU then alters the amount of oxygen
Figure 21: Stock Exhaust System
by adjusting the air fuel ratio. The air fuel ratio should always read 14.7, based on gasoline, when the engine is
warmed up. The exhaust system also has a muffler. Its main function is to reduce sound. Sound is created when
a pressure wave is formed from pulses of alternating high and low pressure. These pulses are created when the
exhaust valve opens. The sound wave enters through the center
tube, bounces off the back wall, is reflected through the hole,
passes through the other chamber and then finally exits out the
back pipe. A sketch of the inside of the muffler is shown in Figure
21. When the sound waves are reflected back they cancel the
incoming waves. This is how the sound is reduced. [8]
Figure 20: Sketch of Muffler Interior
44
7.2 Custom Exhaust
The custom exhaust follows the same path as the stock exhaust. The straight pipe in between the
manifold and the muffler is replaced with a pre-catalytic converter, flexible pipe and catalytic converter. The
pieces are shown in Figure 22. The dimensional drawings of the custom pieces can be found in Appendix C. A
catalytic converter is used to covert harmful pollutants into less harmful emissions. The major emissions are
nitrogen, carbon dioxide and water. N2 is the largest component of air (78%). CO2 and H2O are products of
combustion. If the combustion process were perfect there would be no other emissions. However, it is never
perfect and the result is harmful gases. Smaller amounts of CO, hydrocarbons, and NO and NO2 are present the
exhaust leaving the engine. Carbon monoxide is a poisonous, colorless and odorless gas. Hydrocarbons are
produced from evaporated unburned fuel. The NOx gases contribute to acid rain and cause irritation to human
mucus membrane.
The catalytic converter uses chemical reactions to convert these harmful products into safer gases. The
first stage is referred to as the reduction catalyst. Platinum and rhodium are used as the catalyst to remove the
nitrogen from the NOx gases. This frees an oxygen atom and a nitrogen atom that bond with other similar atoms
resulting in N2 and O2. The second stage used the oxidation catalyst. It is usually in the form of honeycomb (used
in this custom exhaust) or ceramic beads. This material uses both platinum and palladium as a catalyst to burn
the unburned hydrocarbons. The reaction combines CO with O2 to form carbon dioxide. The last stage is the
control system using the oxygen sensor as described above in the stock exhaust section. [7]
Figure 22: Custom Exhaust System
45
8.0 Conclusion
Although our initial project goal of attending the 2012 Clean Snowmobile Challenge proved to be overly
ambitious well before the midway point of the project, the adapted goals were an immense success. The 2012
CSC team has
 provided sound background information on theory governing the snowmobile's functionality,

recorded procedures for acquiring pertinent ECU tuning parameters, and most importantly
 delivered the following team a well running snowmobile, placing them in a position to complete
a project following a strict competition timeline.
Being left in the wake of the less than perfect 2011 season, the 2012 team focused on learning as much as
possible about the Yamaha Phazer and using MicroSquirt as its ECU. The underlying theme of this project, as it is
with much of engineering, was avoiding mistakes made in the past. The snowmobile engine was assembled with
the aid of professional mechanics. The engine has been properly tuned and remains in its current state where it
can be correctly operated using pump grade E10 gasoline fuel. Tuning parameters specific to this exact engine
have been defined and explained. The following team may now begin their project by conducting a series of
baseline tests that include: emissions testing with the 5-gas analyzer, dynamometer testing to verify the current
state of the snowmobile, as well as with the modified exhaust attached to correlate the improvement in
emissions output. As described above, the analysis of the current fuel injection system should be continued. It is
unknown if the stock injectors will be able to perform with fuel containing higher contents of ethanol. Adding a
third injector may help solve the problem. A solution may be to use the triple cylinder set up of the Yamaha Nitro
snowmobile. The following team is in a position to yield compelling results in the 2013 CSC and thus declare
University of Maine as a top competitor in the annual SAE clean snowmobile competition. As successful as this
project was, its overall value will ultimately be determined by the outcome of the following team, and by their
utilization of the information that has been provided within this report.
46
References
1. Bowling, Bruce, and Al Grippo. "MicroSquirt Manual." MicroSquirt. Oct. 2011. Web. Winter 2011.
<http://www.MicroSquirt.info>.
2. Dan, Maslic. Master EFI Tuner, Learn How to Tune GM EFI. 2nd ed. Embex Group, 2011. Print.
3. Frazier PhD, PE, CEM, R. Scott. "Ethanol Gasoline Blends and Small Engines.” Oklahoma Cooperative
Extension Service. Oklahoma State University. Web. Apr. 2012.
<http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-6015/BAE-1746pod.pdf>.
4. "Gasoline Gallon Equivalent." Wikipedia. Wikimedia Foundation, 2011. Web. Winter 2011.
<http://en.wikipedia.org/wiki/Gasoline_gallon_equivalent>.
5. Jorgensen, S., Furey, R., and Perry, K., "A Simple Method to Determine the Methanol Content of
Methanol Fuels," SAE Technical Paper 912421, 1991, doi:10.4271/912421.
6. Lucius, Jeff. "Injector Duty Cycle Calculation." Stealth 316. K2 Software, 2005. Web. Spring 2012.
<http://www.stealth316.com/2-calc-idc.htm>.
7. Nice, Karim, and Charles W. Bryant. "How Catalytic Converters Work." HowStuffWorks.com. 8 Nov.
2000. Web. 27 Mar. 2012. <http://auto.howstuffworks.com/catalytic-converter.htm>.
8. Nice, Karim. "How Mufflers Work." How Stuff Works. 19 Feb. 2001. Web. 20 Oct. 2011.
<auto.howstuffworks.com/muffler.htm>.
9. "SAE Collegiate Design Series: Clean Snowmobile." SAE Collegiate Design Series: Clean Snowmobile
Challenge. SAE International, 2012. Web. 2012. <http://students.sae.org/competitions/snowmobile/>.
10. "Safety Data Sheet." 6 June 11. Web. 20 Apr. 2012. <http://www.packserv.com/Data/Products/DataSheets/-545858346.pdf>.
11. "Timing Advance for E85 and Ethanol." E85Forum.com. PhpBB Group, 2005. Web. Spring 2012.
<http://e85forum.com/about771.html%5C>.
12. Tsuneishi, Scott. "E85 Vs. Conventional Gasoline." Import Tuner. Source Interlink Media, 2012. Web.
Spring 2012.
<http://www.importtuner.com/tech/impp_0904_e85_vs_conventional_gasoline/viewall.html>.
13. Yamaha Service Manual 2007 Phazer. 1st ed. Yamaha Motor Corporation, 2006. Print.
47
Appendices
Appendix A: Engine Assembly
The engine was assembled using the following process. [13]
1. Honed out the cylinders, using a honing tool, to give them a mirror finish ( This insured that the rings
would seat properly)
2. Put a small amount of oil in the cylinders and spread with finger
3. Cleaned where bearings sit on connecting rods and changed bearings on connecting rods, being careful
not to touch
4. Sanded where the head gasket sits to prevent burs
5. Made sure rings were lined up properly according to the diagram on page 5-74 of manual
6. Put ultra-slick assembly oil on pistons and worked it into the rings
7. Put ring compressor around piston, tightened until oil came out
8. Matched pistons to the correct cylinder by matching the connecting rods to the correct position on the
crankshaft. (Had to determine the magneto side, the “Y” on the connecting rod faces it)
9. Put lubricating assembly grease on connecting rod bearings
10. Lined up piston with cylinder and knocked first piston through the ring compressor, into the cylinder
with the handle of a mallet
11. Second piston was not lined up correctly and the oil ring was bent during installation. (Had to get a new
set of rings for piston).
13. Attached first connecting rod to crankshaft, torqued both bolts to 14 ft-lbs +120 deg (4 notches on bolt
head) using torque wrench.
14. Put new rings on piston according to diagram and put ultra-slick assembly oil on the rings
A.1
15. Placed ring compressor over piston (Using a different type of compressor tool this time)
16. Put oil in cylinder and assembly grease on connecting rod bearing
17. Lined up piston with cylinder and knocked it into the cylinder using the handle of a mallet
18. Greased the other side of the connecting rod bearing and bolted it to the crankshaft, tightening the
bolts to 14 ft-lbs +120deg using torque wrench
19. Lubed the o-ring on the oil cooler
20. Put dowels in appropriate holes on upper crankcase
21. Cleaned both sides of crankcase mating surfaces and put Yamaha 4 liquid gasket on upper side of
crankcase
22. Put assembly grease on lower crankcase bearings (where crankshaft sits) and placed lower crankcase on
top of upper crankcase
23. Oiled bolts and threaded into crankcase according to the number system on the bottom side of
crankcase
24. Tightened the 6 bolts to 11 ft-lbs with torque wrench, and then re-tightened to same torque. Bolts were
then turned another +65-70 deg ( 60deg is one flat on this bolt)
25. Located the other 5 types of bolts needed to fasten the upper and lower crankcase, placed them in their
appropriate positions
26. Flipped assembly over to put 3 bolts in their appropriate holes
27. Checked to make sure there was end play in the crankshaft
28. Applied loc-tite to appropriate bolts and tightened all bolts to 8.7 ft-lbs.(9 due to scale on torque
wrench)
29. Installed oil pump assembly (used liquid gasket/did not have real gasket)
30. Put oil pump driven sprocket and chain around crankshaft gear
A.2
31. Spread liquid gasket on mating surface of upper crankcase
32. Attached oil pan on mating surface of upper crankcase
33. Located 13 allen head bolts to secure oil pan. Bolts were torqued to 7.2 ft-lbs (7 due to scale of wrench)
34. Inserted chain guide around timing chain and screwed in bolts to secure it
35. Put magneto rotor on the end of the crankshaft after cleaning both pieces
36. Aligned the pin on the bolt to secure the magneto then bolt was torqued to 94 ft-lbs
37. Cleaned magneto rotor casing and placed the gasket on the mating surface.
38. Secured casing (loc-tite applied on black bolts) and torque all bolts to 8.7(9) ft-lbs
39. Water pump was attached with 3 bolts that were torqued to 8.7(9) ft-lbs
40. Tightened band clamp on water pump hose
41. Put chain guide in on balancer side (realized we needed to put in before setting crankshaft, now need to
pull crankshaft gear off)
42. Pulled gear off using gear puller( very difficult because bolt to secure gear had been over tightened and
broken off)
43. Put in timing chain guide and placed gear back on (making sure to line up the low spline)
44. Threaded gear bolt back on(left-hand thread) and torqued to 54 ft-lbs (put screwdriver between gears
to hold gears from turning)
45. Folded flap up around head of gear bolt
46. Put primary drive sheave in making sure to line up the “c” on all 3 gears
47. Put gasket on and attached casing with allen head bolts ( applied loc-tite to black bolts ) and torqued to
8.7(9) ft-lbs
48. Tightened 4 bolts around drive shaft to 8.7(9) ft-lbs
49. Used sand paper wrapped around a file to clean the head off where the gasket sits
A.3
50. Placed head gasket around cylinders and set head on top, feeding the timing chain through the head
gasket and head
51. Lined up double dash marks on magneto rotor with the stationary pointer to make sure timing is
correct(had to use a flashlight to see marks on the rotor)
52. Tightened the head bolts in correct sequence (according to diagram on page 5-30 in manual)
53. Torqued the bolts to 18 ft-lbs, then loosened and tightened to the same torque ( to make sure head was
aligned properly) then bolts were turned another +180 degrees
54. Made sure dash marks on magneto rotor were still lined up with the pointer
55. Hooked timing chain to camshaft sprockets
56. Put intake and exhaust camshafts caps over the cam shafts
57. Attempted to torque the bolts on the intakes camshaft cap ( chain kept falling off until we realized we
needed to install the timing chain tensioner)
58. Installed the timing chain tensioner and lined up all marks on camshaft gears, making sure dashes on
magneto rotor were also still aligned
59. Removed spark plugs from head cover
60. Squeezed Yamaha 4 liquid gasket inside head cover gasket
61. Placed gasket on head and put head cover on top of gasket
62. Torqued allen head cover bolts to 8.7(9) ft-lbs (had to reset head cover because gasket did not align
properly first time)
63. Turned drive shaft to make sure timing chain was securely set on the camshaft sprockets
64. Oiled seal on oil filter and screwed it onto engine
65. Attached throttle bodies and tightened band clamps to secure them
A.4
Appendix B: Flow Bench Parts Details
Table B-1: Flow Bench Parts List
Part Number
555-100911
555-100021
361-804606
Description
Braided Steel Hose 6 AN
90o Female 6 AN to Hose Fitting
45o Female 6 AN to Hose Fitting
180° Female 6 AN to Hose Fitting
361-925106 T-Fitting 6 AN Female Swivel on Branch
555-100242 Flare Bulkhead Fitting 6 AN Straight
555-100333 6 AN Female to 3/8” Male NPT
555-100222 8 AN Female to 6 AN Male Reducer
361-992908 8 AN Fitting Cap
361-300106 Female 6 AN to Hose Fitting Straight
361-840106 Male 6 AN to Hose Straight Adapter
023-FBM2978 90° Female 6 AN to Female Swivel Coupler
555-100322 Female 6 AN to Female 6 AN Adapter
JIF-31506
Jiffy Tite 3000 Series 6 AN Quick Connect Female
128-3039
Male 6 AN to 10 mm Adapter
400-920
Fuel Pump Mounting Hardware
GSL414
Walbro Fuel Pump
555-15032
Fuel Filter
1728
Edelbrock Fuel Pressure Regulator
1069-6AN
Fuel Pressure Gauge 1/8” NPT
821-2010A
RCI Aluminum Fuel Cell
N/A
8 mm Rivet Nuts
N/A
Mineral Spirits
N/A
6061 Aluminum 1 in. hex stock
N/A
1 in. square stock
N/A
16 gauge stainless steel (3ft x 4ft)
B.1
Supplier
Quantity
Jegs
12 ft
Jegs/Summit Racing
10
Jegs
1
Jegs
1
Jegs
1
Jegs
2
Jegs
2
Jegs
2
Jegs
1
Jegs
2
Jegs
3
Jegs
2
Jegs
1
Summit Racing
1
Auto Performance Engineering
2
Auto Performance Engineering
1
Auto Performance Engineering
1
Jegs
1
Performance Parts
1
Pegasus
1
Jegs
1
Fastenal
25
Central Storage
1 Gal
Lane Supply
1 ft
Lane Supply
2 ft
Lane Supply
1
B.2
B.3
B.4
B.5
B.6
B.7
B.8
B.9
B.10
B.11
Appendix C: Custom Exhaust Parts
Note the following drawings are not at 100% scale as shown, but dimensions are correct.
C.1
C.2
Appendix D: Budget
Entire Project Total
$4971.74
Snowmobile Assembly and Repair Total
Piston Rings
Rivnut Kit
Sensor Replacements and Parts
Battery and Spark Plugs
Coolant, Tubing, Fuel Line, Hose Clamps
5 Gas Analyzer Parts
Fuel Pressure Gage
Exhaust Parts and Repairs
Touch Screen and Computer
$2843.99
$35.00
$83.00
$610.57
$123.27
$101.40
$412.00
$41.95
$1074.44
$362.36
Flow Bench Total
Arduino Kit
Graduated Cylinders
Fuel Pump, Regulator, Fittings, Filter, Line
Fuel Cell and Caps
Pressure Gage
Test at Diesel Fuel Systems
Mineral Spirits
Aluminum and Stainless Steel
Wiring
O-rings
Rivnuts
$1816.55
$94.95
$60.06
$1246.54
$174.30
$54.37
$40.00
$19.62
$83.97
$23.54
$9.80
$9.40
Cosmetics Total
Bondo
Primer, Paint, Sealer, etc.
Trim
$311.20
$33.58
$258.93
$18.69
D.1