FHR23 EVO Design Recap
Updated: Mar 4
Welcome to our first design recap! The goal of the recap is to provide information on what changes we are looking to make, along with some insight into our process behind why and how changes are made within our design. Our design window primarily runs through the fall semester. The following sections include major changes, minor changes, and then other projects within the team.
We do have an ongoing fundraiser located here: https://crowdfunding.sdsmt.edu/organizations/formula-hardrocker-racing
This years car is an iterative evolution off of FHR22 from last year; hence the name of FHR23 EVO. The FHR22 was reliable and performed well enough, but we knew we left some performance on the table. We chose to use it's design as a platform to build off of, and improve. We look forward to getting maximum performance from the design this season.
Overview of FHR23 EVO
Engine: Honda CBR600RR
Transmission: Stock CBR600RR 6 speed transmission
Wheels: 10’’ Magnesium OZ Racing center lock wheels
Tires: Hoosier R25B 18x6-10 race slick
Suspension: Pull rod suspension both front and rear, with lightweight carbon fiber control arms
The intake side of our engine has been a primary focus this year. A senior design team was set up to gather data and engineer an optimum manifold for our current package, or a manifold that can easily adapt to other similar applications with minimal loss of performance. The verification data is useful for future design team decisions, and is exactly what the judges at competition like to see.
Realis WAVE, formerly Ricardo WAVE, was a new software tool for our team. To keep it short, WAVE is a 1D simulation that allows for someone to change and analyze any and all components of an engine with great accuracy. The team used WAVE to determine the ideal volume and shape of our intake manifold to maximize airflow with minimal turbulence.
A variable test manifold was then created to verify the software's output and fine tune our final settings. This plenum was an aluminum pipe with threaded plungers on either end allowing us to adjust the internal volume. The test manifold also had easy to change runners so we could test the effect of different runner lengths.
This spring, the test manifold was installed on our dyno bike and numbers were gathered over multiple dyno runs. This verified that WAVE was very close to real life and gave us the confidence to move forward with fabricating and testing a couple final designs. The final design will include a 3D printed ABS plenum, carbon fiber runners, and AT Power restricted throttle body.
Last year the aero package was designed to be unsprung, but ran into time and manufacturing difficulties preventing completion before competition. Due to the manufacturing difficulties experienced, the team has shifted back to a traditional chassis mounted design for this year.
We are using a new manufacturing technique for the wing elements this year. Last year the wing elements were made using a foam cutter and wrapping carbon fiber around the foam. This proved to be extremely labor intensive as the foam cutter did not work well. We now have machined two part molds for all of the wing elements. We will layup the carbon as a top and bottom and glue these halves together with a combination of 3-d printed and aluminum ribs. The attached renders show off the elements.
The overall goal of the electrical system this year is similar to the previous cars, but with improved devices, form, and functions. We utilized Rapid Harness to design the entire professional motorsport-level harness before building it, allowing for a much cleaner harness with fewer cable bundles as well as easier diagnostics.
Custom professional motorsport-level harness using Tefzel wire, Raychem DR-25 heat-shrink tubing, and Deutsch connectors
MoTeC M130 Engine Control Unit
Custom Power Distribution Module
AIM Solo 2 DL digital dash/logger with GPS and accelerometer
Capabilities for separate high level data logging devices for measuring suspension performance, vehicle performance, tire temperatures, etc.
MoTeC Development License
A MoTeC Development license allows a user to build a custom MoTeC Project. The Project contains all of the functions, internal calculations, and input/output methods that will be used to operate the combustion engine. This M1 Project can then be opened as a Package in M1 Tune where engine parameters can be calibrated and tables can be populated.
With the focus on the intake design for the powertrain system, the previous MoTeC Package was deemed insufficient. The main issue being that the previous Package was locked into a throttle position based load calculation and engine efficiency method, known as Alpha-N.
While a TPS based method may be easier to understand, a manifold pressure based model will always be more accurate and better at determining the airflow inside the engine, so the team changed to a pressure based airflow metering method known as Speed Density. The dev license would also be used to make some necessary I/O adjustments as well as remove certain validation limits to ensure functions would work correctly with the new powertrain package.
The firewall between our cockpit and engine will see some refinement this year. Time constraints left us with a crude firewall last year that was all function with no form. It was ugly. This year’s firewall had more time dedicated to designing and manufacturing, and will also aid our electrical system team. We are adding an access panel to allow easier access to our electrical system without sacrificing packaging.
We are making the switch to E85 for our fuel this year. E85 is an ethanol and gasoline blend consisting of about 85% ethanol. The octane rating is between 100 and 105, compared to the 91 to 93 octane pump gas we have run before. Higher octane fuel can withstand greater pressures before pre-ignition, which allows us to advance our timing and gain slightly more power. The tradeoff is less fuel efficiency, but our fuel system is designed to account for the extra fuel required. Part of this switch involved E85 compatible parts, so we have a fuel pump and injectors from DeatschWerks, and Holley Hydramat within our fuel cell.
The pedal box is a great example of a minor iterative adjustment based on lessons learned. The aluminum bracket that the throttle cable was mounted to was in a position that the driver’s foot could make contact with it. It received more force than it was designed for, and developed a slight bend during endurance. The result is we lost some throttle position travel, which prevented the ECU from entering “Clear Flood” mode. This small bend ended our endurance run. The new pedal box has been modified to address this issue.
The overall suspension design remains the same, but minor improvements have been made. Rocker geometry was altered using Optimum-G to provide less compliance, and the material was changed from steel to aluminum. The camber adjustment was moved from the frame side to the knuckle side for ease of adjustment. Our stub shaft was changed to accommodate our new center lock wheels.
Other Team Updates:
An electrical engineering senior design team is tackling the project of installing a Brammo motor into our frame from 2013 for FHR. The goal is to have a drivable car by the end of the semester, albeit not in competition spec. There will come a day that FHR will switch from internal combustion to the electrical vehicle class. The knowledge gathered from this project will lay the foundation for our future cars, and will be of great use to our team in the future.