- The Engine subsystem focused on rebuilding engines for the 2015 vehicle to ensure reliability. They rebuilt one engine as a test case. - Tuning on a dynamometer resulted in a 23% increase in horsepower from 45 to 59 horsepower. - Lessons from the first rebuild included being more organized to avoid losing parts and contamination, as well as planning part orders more carefully to save time and money.

1. Engine Internals
Design Report
Van Le
March 2015

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TABLE OF CONTENTS
Abstract………………………………………………………………………………………………....……3
Overview………………………………………………………………………………………………………3
Obstacles and Problems………………………………………………………………...…………………3
Engine Decision………………………………………………………………………………………………3
Decision Matrix……………………………………………………………………………………..4
2015 Design…………………………………………………………………………………………………..5
Rebuilding……………………………………………………………………………………….……………5
Testing and Tuning…………………………………………………………………………………………6
Mistakes and Precautions for the Future………………………………………………..…………….6
2016 Design……………………………………………………………………………..……………………7
Internal Components………………………………………………………….……………………………7
Shaving & Rebalancing…………………………………………………….………………………………8
Changing Motors…………………………………………………………….………………………………8
Changes for the Future…………………………………………………………………………………….9
Hiccups…………………………………………………………………………………..………………….…9
Evaluation Checklist………………………………………………………………………………………10

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ENGINE INTERNALS DESIGN REPORT
Abstract
For the 2015 vehicle, the Engine subsystem aimed to pay closer attention to the motor
of the vehicle, as it was the cause of a few major issues in the past. The priority was to take
engines and rebuild them to ensure that every internal component was functional and within
proper tolerance and in order for us to be pushed the vehicle to its limits. This year’s formation
of a dedicated engine subsystem would take on this task and ensure the reliability on the
team’s engines. The subsystem goals were to successfully rebuild all of the team’s motors and
eliminate the risk of any damage or failure of the vehicle or its critical parts due to an engine
failure.
Overview
The Engine subsystem became an established subsystemat the beginning of the 2014-
15 season, therefore not much design has been put into the design of the 2015 vehicle. This
report will discuss any minor design decisions applied to the 2015 vehicle, as well as elaborate
more on the design process for the 2016 vehicle in comparison to the design process of the
2015 vehicle. For the 2015 season, the subsystemprimarily worked on engine rebuilds that will
be implemented into the 2015 vehicle, while simultaneously practicing clean and organized
methods for the 2016 season. In cooperation with the Electronics subsystem, the Engine
subsystem took the vehicle to a dynamometer for engine tuning to optimize performance while
considering the 20 mm air restrictor. This report will discuss the design features, failures, issues
the subsystem encountered, and the steps the subsystem took or should have taken to
overcome those issues.
Obstacles and Problems
The most prevalent obstacle was the lack of knowledge of the Honda CBR600 F4i motor
and thus the first rebuild took much longer than expected. Coupled with the subsystem’s
relatively new formation, the inexperience from the subsystem members hindered progress.
Because the subsystemwas rather new, not many people were very interested in joining a
subsystem that had no prior knowledge to guide them. Those who did join soon left the team
due to lack of commitment. Parts were ordered late and the time for them to ship was not
considered, further hindering the subsystem’s progress.
Later in the season, the subsystem pulled through and worked diligently making up for
lost time. Even though only one engine rebuild was complete, this urges us to complete the
other rebuilds faster, however without rush and more organized.
More issues will be elaborated in the “Mistakes and Precautions for the Future”
paragraph.
Engine Decision
For the 2015 vehicle, the team decided to switch from a 2006-2007 Suzuki GSX-R to a
2001-2003 Honda CBR600-F4i. In hindsight, the GSX-R was a poor choice in a motor. It was
unreliable and produced low amounts of torque, which was most likely due to the unreliability
and therefore the overall quality of the engine purchased. However, it was an easily accessible

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motor and a familiar engine to the team. Even so, the GSX-R caused numerous problems in the
testing phase that year and so the team found it fit to change the motor. A practical decision
matrix was created and evaluated between eight engines, including the 07-08 GSX-R.
Category Weight
GSXR
01-03
GSXR
04-05
GSXR
06-07
CBR RR
05-06
CBR RR
07-08
R6
03-05
R6
06-07
CBR F4i
01-03
Availability 6 1 2 2 2 2 0 -1 1
Reliability 9 1 0 -2 1 1 2 2 2
Familiarity 1 1 1 1 1 1 0 0 0
Torque 4 0 0 -2 0 0 1 1 0
Cost 7 2 2 1 0 0 -2 -1 1
Total 27 30 27 -6 22 22 8 9 31
The CBR600 F4i prevailed in the decision matrix by being the most reliable and being
relatively inexpensive and available for purchase. This significantly reduces the risk of losing a
motor due to engine failure and suits the team’s constraints regarding time and funds, as losing
a motor would be detrimental to both of these factors. The F4i produced a lesser amount of
horsepower (110.2 hp as opposed to 125 hp) and put out slightly less torque (47.94 lb-ft as
opposed to 49.93 lb-ft.) However, the losses in power and torque were decisively minimal
enough that the reliability of the engine far outweighed the performance loss.
Honda CBR600 F4i Suzuki GSX-R600
Max Power 110.2 HP @ 12500 RPM 125 hp @ 13500 RPM
Max Torque 47.9 ft-lb @ 10500 RPM 49.9 ft-lb @ 11500 RPM
Compression Ratio 12.0:1 12.8:1
Piston Bore and Stroke 67.0 x 42.5 mm 67.0 x 42.5 mm
Cost $511.22 $619.99
Advantage Reliability Power

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A quick analysis of the registered teams for the 2013 and 2014 Michigan FSAE
competitions showed that more teams ran the F4i. Not only did more teams use the F4i by
about 8-10% more than the GSX-R,
the use of the F4i increased more
than the increase of the use of the
GSX-R between the two years.
The only downfalls to
choosing this motor were that the
team was unfamiliar to the model
and the motor had a rather low
rating of torque. The only reason
the team did not choose the
second highest ranking motor, the
2001-2003 model of the GSX-R,
was because it was more
expensive and less reliable, two
factors that were taken in heavier
consideration this year (notice the
“Weight” column).
2015 Design
The general priority was to decrease the vehicle’s weight as much as possible. On the
engine, the swing arm mount was not being used and therefore, rendered useless to us. The
mount was cut off, which was able to shave off 0.66 kg (1.45 lb). Each engine prior to rebuild
was cleaned up and painted black with
engine enamel in order to create a visually
appealing motor, but to maintain
cleanliness.
No modifications will be done to
the engine this year due to the recent
addition of the Engine subsystem and the
inexperience of its members. However,
research for design for next year is already
underway. The first rebuilt engine will be
the team’s spare engine.
Rebuilding
The rebuild was kept simple; only necessary parts were replaced. Any parts that were
susceptible to wear were replaced, mainly any bearings or gaskets. Gaskets and o-rings were
replaced to ensure proper sealing. New piston rings are essential to the pistons’ proper
function. The crankshaft and connecting rod bearings were all replaced to eliminate previous
wear. A crankshaft needle bearing was purchased however not used due to time constraints
and the time-worth value of the procedure. It will however be replaced for the next engine.
The first CBR F4i engine in the progress of being rebuilt
13%
16%
5%
6%
0% 5% 10% 15% 20%
2013 Michigan
2014 Michigan
Percent of Teams
Percentageof Teams Running GSX-Rvs
CBR 600 F4i
Suzuki GSX-R 600
Honda CBR 600 F4i

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Testing and Tuning
The team took the vehicle to a dynamometer and performed ECU tuning to optimize the
AFR and timing for the vehicle. Prior to tuning, the car output 45.3 horsepower and afterwards
the car output 58.6 horsepower, a 22.67% increase in power. The goal was to produce
maximum power between 8000 RPM to 11000
RPM, which was the rev range in which the car
would be at the majority of the time in lower
gears. After tuning, the maximum power
output was approximately 105000 RPM, which
satisfied the goal. The vehicle put out 31 lb-ft
of torque after the tune. The air-fuel ratio
(AFR) has been tuned to 12.5 at wide open
throttle. Looking at Figure 1, notice that the
drop found at about 5300 RPM of the green
curve disappeared after the tune. The team
used wide-open throttle tuning: fully
depressing the accelerator while allowing the
dynamometer’s load to steadily increase the
RPM of the vehicle across the power band
(4000-145000 RPM). The first dynamometer
run is to pull data to find the base power and
torque curves. These curves tell you the output
power and torque at a certain RPM range, and
from that, you can tune the air-fuel ratio (AFR)
and valve timing accordingly. The objective is
get as much area under the curves as much
possible or in other words increase the height
of the curve as much as possible. The AFR is determined by the best resulting curve in that RPM
range. From that value, the AFR is adjusted along intervals of RPM to find the best AFR across
the power band (in this case, 12.5). After tuning for AFR, the ECU was tuned for valve timing, or
the time in which the valves are open to take in air. This is determined by the AFR and is
combustion behavior. If the mix is too rich, the timing is decreased. If the mix is too lean, the
timing is increased.
Mistakes and Precautions for the Future
During, the first rebuild, a few parts were lost due to unorganized methods. This cost
the subsystem time and money because it took lots of time for ordered parts to come in. A
thorough read of the owner’s manual is necessary to ensure all parts necessary for the rebuild
will be ordered all at once. During the rebuild process, dust and metal bits are liable to fall into
the cases and should not be allowed to happen. All parts should be cleaned before replacing
them. Contaminants should not be allowed in the engine block because that can cause
potential major damage.
It is advised to be extremely careful of torqueing bolts to specification. Multiple times
have torqueing bolts led to snapping them due to the incorrect torque setting. Always test the
Fiq. 1. The power curves for before and after tuning.
The green curve represents the power/torque curve
prior to tuning and the gray curve is the
power/torque curve after tuning.

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torque setting on an old useless bolt or gauge it by feel. Snapping bolts will consume time and
lose parts. The driveshaft sprocket bolt and one of the clutch hub bolts were snapped this way.
It is highly recommended that the right tools be used for the rebuild. We were without a
clutch hub holder which was the subsystems biggest setback. We managed to use the impact
wrench to tighten the clutch hub lock nut. However, it was not exactly torqued to specification
due to the lack of the holder.
Tolerancing was not very stressed in the first rebuild and should be the second time.
Only the camshaft, the piston rings, and the crankshaft were tolerance. Next rebuild, there
should be more focus on the tolerancing of all of the components to further ensure the
reliability of the engine.
2016 Design
For 2016, our main priority is to research internal components that can be modified
without a significant risk factor. The Engine subsystem wants to try to take the modification
process one step at a time because the engine is an extremely important system that most
other systems rely on. Therefore, the subsystem must be cautious with our modifications or
else risk the chance of damaging motors. The subsystem wants to keep rebuilding engines as its
main purpose while exploring different methods to optimizing the vehicle’s performance.
Internal Components
The first major step towards internal engine component modification will be custom
cam lobe profiles. Coupled with proper tuning, custom camprofiles will enhance engine
volumetric efficiency by allowing optimal power levels for the restricted air intake. Aiming for
low-end and midrange power, decreasing valve overlap can decrease the duration of the lobe
and tighten the lobe separation angle (LSA), resulting in an increase of low-end torque. At lower
RPMs, the valves will open for shorter periods, utilizing that initial burst of high velocity and
inertia of the exhaust gases exiting through the exhaust valves for an efficient pull.
Adjustable cam timing gears offer an easy way
to adjust the power band by advancing or retarding the
valve timing. By advancing the timing, there is an
increase in low-end torque and shift in the torque
curve towards lower RPMs. The intake event begins
sooner therefore pushing to get as much air into the
cylinder as possible.
An idea for a thinner head gasket is also being
considered. A thinner gasket will increase compression
and tighten quench area. This will improve the
combustion rate and quality, improving overall power.
Enhanced valve springs may be a component to
consider modifying as they are important for the lifter
to remain in contact with the cam lobe and improve
durability. Other smaller improvements to enhance to
engine performance are porting and polishing will
improving volumetric efficiency and improve the quality

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of flow rate, however there is the possibility of a minute loss in air velocity causing a lack of low
RPM power.
All internal component modifications will be followed by a proper tune to ensure the
engine runs properly.
Shaving and Rebalancing
A less practical but very possible modification can also be taken into the design process:
grinding and rebalancing the crankshaft counterweights and connecting rod ends. This will
decrease rotational weight and shave off a small amount of mass from the engine, and thus
increase rotational speed resulting in a rate increase of RPM.
Changing Motors
Another option to consider is to completely change the motor. Instead of using 600 cc 4-
cylinder engines, it is possible that the team could employ a 450 cc single-cylinder engine or
perhaps a 450 cc twin cylinder*.
Honda CRF 450X Yamaha WR450F Yamaha YFZ450* Honda CBR600 RR
449 cc 450 cc 449 cc 599 cc
44.8 hp @ 7500 RPM 58.0 hp @ 9000 RPM NA 118 hp@ 13500 rpm
31.7 lb-ft@ 7000 RPM 33.1 lb-ft@ 7000 RPM NA 48.6 lb-ft@ 11250 rpm
12.0:1 12.5:1 11.4:1 12.2:1
96.0 x 62.0 mm 95.0 x 63.4 mm 95.0 x 63.4 mm 67.0 x 42.5 mm
$2,349.95 $2,137.25 $1,499.99 $952.49
Theoretically, these engines would perform better than the four-cylinder engines as it
would not require as much air to perform well, which suits the air restriction constraint. If the
team were to then further enhance the performance of the
single-cylinder engine, that would increase power while not
encountering the problem of choking the engine. Not only would
the single-cylinder possibly be more efficient, but it would also
be lighter. However, these single-cylinder engines are rather
difficult to find, are extremely expensive, and would require the
team to completely redesign for a new engine and create more
room for error and design failures.
This is why the team may consider the Honda CBR600 RR.
Despite the results of the decision matrix (CBR600 RR: 22 as
opposed to CBR600 F4i: 31), the RR engine is known to be more
aggressive rnd powerful than the F4i, while still being extremely reliable. It costs approximately
$400 more than the F4i, however the power output of the engine are worthy to consider.
The RR utilizes Honda’s PGM-DSFI systemor programmable dual state fuel injection, as
opposed to the F4i’s older PGM-FI system. With the dual stage injection, there is a systemof
Honda CRF450X

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two injectors, one positioned at the bottom, and one above it.
The lower injector is active during low-end RPM and after 5500
RPM, both injectors are activated. The upper injector is
controlled by the ECU, so that the upper injector activation
timing is able to tune. The lower injector is meant to enhance
rideability and the upper injector is meant to enhance top-end
horsepower.
Another advantage the RR has over the F4i is that it is
lighter by 4.4 lbs and is much more compact, allowing us to have
more room for other structural components, as well as having the
ability to decrease the center of gravity of the vehicle. Despite this, the CBR F4i has proven to
be a reliable motor that the team has already designed their components for, thus the team will
not be changing the motor for next season.
Changes for the Future
For the future, the Engine subsystem will use 1-D gas dynamic software to study the
flow of the air-fuel mixture to determine modification decisions and to better understand
engine theory. Ricardo WAVE and Gamma Technologies GT-Power are both engine simulation
software that will allow us to analyze flow rates. The team will utilize the engine dynamometer
throughout the design process to test the engine modifications and collect relevant data to
observe the changes made, whether positive or negative. This focus on engine design and
testing will factor into learning engine theory, which should be stressed as being a part of the
engine subsystem.
Hiccups
Several factors went into the failure of the engine subgroup to meet its deadline. The
first and most prevalent issue was that the subgroup was comprised solely of new team
members who were not used to the demand of work required in the team. Our lack of urgency
in the beginning of the year reflected in our last-minute efforts before the running-car deadline.
It was my fault that the subgroup did not work as much and as hard as we did, and therefore
we fell behind. Being a new member as well as taking on the responsibilities of being a design
lead set us back as I did not live up to said responsibilities of a design lead. This fact then
resulted in our other setbacks, including ordering parts late and an unnecessarily long and
unorganized rebuild. The subgroup was not very consistent in showing up to the shop and so
progress was further deterred.
For next year, I will build a stronger subgroup so that our combined efforts will meet
and exceed our goals, as well as the team’s. Engine rebuilds will go much quicker and smoother,
taking the minimal time necessary. Everyone in the subgroup will have a weekly deliverable to
me, speeding up the process. I hope that my experiences as lead from this year will help me in
the next.
Honda CBR600RR

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Evaluation Checklist
Pre-Ignition
□ Check spark plugs
□ Check oil level
□ Check for broken gaskets/oil leaks
□ Check for loose/missing bolts
Post-Ignition
□ Listen for unusual sounds and noises
□ Check for oil leaks
Take note of all abnormalities and record major abnormalities.Do not startthe vehicleuntil all issues havebeen
evaluated and resolved. Immediately shutoff the engine if unusual sounds and noisesarecomingfrom the engine
whilerunning.