(Originally posted 12/22/2016, Moved to WordPress 1/16/2017)
In college I helped out on the Formula SAE team here and there but was never a fully committed member. Looking back, I wish I had made more time to be more involved (but I guess my priorities were in a different place). I loved the idea of using a sportbike engine with its integrated sequential transmission in a super lightweight car and I thought it would be really fun to be able to drive it around on the street (now that I’m older, I don’t think I would drive a car THAT small around with 5,000 lb. SUV’s next to me).
Anyway, at that time, the car I was sketching and dreaming about was a slightly scaled up Formula SAE car with a Hayabusa engine mounted behind the driver and driving the rear axle by chain. It would have been similar to a D Sports Racer of the time but with more ground clearance (for street use), less aero, and no race series rules to adhere to. Something like these:
I graduated in 2004 and bought my STi in 2005 and my interest shifted more towards making power. I got really into ECU tuning. I made a “road dyno” spreadsheet and I would spend hours every night making small adjustments to timing or fuel (or wastegate duty cycle, etc.) tables and then going out for “Dyno runs” on the empty frontage road near my house. Come home, input the data log into the Dyno Spreadsheet to see if it made a difference, and repeat.
I also started doing track days with that car which renewed my interest (obsession?) with minimizing weight. I could feel more handling (and lap time) improvement by taking 50 lbs. off the front of the car than I could feel by upgrading springs or swaybars. (Of course, playing around with ideas for lightweight track parts also led to the creation of Oswald Performance in 2009.)
As years went by, the concept in my head evolved into more of a street-legal formula car with the drivetrain from a front-wheel-drive car mounted in the back. A little bigger and heavier than my original concept but it would avoid the potential weaknesses associated with using a motorcycle transmission and chain drive in a heavier vehicle than they were designed for. It also avoids the complexity of adding a reverse system to the motorcycle drivetrain. The concept was becoming more track-focused and less Autocross- or street-focused.
This is roughly where I started with the concept for the current “TT1”. I was actually calling it the “TT3” because my goal was to build it to compete in NASA’s TT3 Time Trial class. That goal (and nickname) was bumped up to TT1 fairly quickly and is still used as a guide when making some design decisions but the purpose of the car has now shifted more towards the street (more ground clearance, less aero, etc). With that said, it should be very fast on the track and I am keeping it TT1 legal (so far) so it will be interesting to see how competitive it ends up being (I plan to get into some of the details regarding NASA TT rules in a future post).
In the picture above, I was planning to use a Honda B18 engine transverse-mounted with its standard FWD transmission. A lot of kit cars are built this way and I think it works well for a two-seater but the FWD drivetrain was just too wide for the formula car styling I was going for at the rear of the car. Here are some pictures of VERY preliminary bodywork ideas at that time:
The picture with the red bodywork really shows how bulky the rear end looks. The engine also sat further rearward than I wanted, the rear suspension arms were shorter than I wanted, and it was difficult to get much diffuser volume without raising the engine (and the center of gravity along with it). For comparison, here is a picture that shows how much narrower the rear end is with the longitudinal engine and transaxle:
Well, I meant for this to be a quick summary of the early concept development leading up to the current TT1 design so I have probably rambled on long enough. In my next post I am planning to get into more detail on a few areas of the current design. Thanks for reading.
– Mickey Oswald