Damn, Bruno's getting to be a valuable guy to have around here; first the heads-up on hydraulic hybrids, and now some inside dirt on Formula SAE. A former member of the University of Michigan team, Bruno offers up the scoop: [UPDATED: Another Berkeley team member just weighed in. Check it after the jump.]
-Davey G. Johnson
"There s about 140 or so schools that build a Formula SAE car every year. They are mostly powered by inline 4 motorcycle engines (Honda CBR, Yamaha R6 ), with a 20 mm intake restrictor to keep the power down. Some are turbocharged and most of them have custom fuel injection systems. The 90 hp for the UC Berkeley car is good, but I doubt it s the highest ever. The cars tend to weigh in at about 400 to 550 lbs, go 0 to 60 in 3 seconds or so, pull over 1 g on a skidpad, The competition in Pontiac is interesting to see the ingenuity of the all the students (and the sometimes not-too-pretty solutions)."
Because of the intake restriction, the turbo is necessary to get back the lost horsepower; modern 600cc Supersport bikes are generally making right around 100hp, so even with the turbocharger, the Cal car doesn't have the power of the donor motorcycle. Cal team leader Travis Lee fills us in on their mill:
"We're running a Suzuki GSX-R600 with custom JE pistons to lower the compression ratio for our turbo (Garrett GT-12)."
Berkeley Club co-founder and former engine man Kirk Feldcamp explains more about the mill:
"I thought I'd set the record straight on "Cal having the most power in the country". We'll, the truth is a "sort of". The motor does have the capability to make 92-95hp on the dyno, no problem. Like you said, it's an issue of for how long. We pulled back the timing a bit (the plugs were showing a touch of detonation) so it's now sitting at a peak of 90 hp. At the competition in part years the maximum power I've heard of is 95 from Cornell. To put it in perspective, most teams run naturally aspirated
and make on average ~70hp, while the very best NA teams are making 80ish. Basically this puts us in the top 5% of cars at the Detroit competition... But anyone with a turbo can add some timing and lean it out a bit to make a 95hp dyno-queen pull. Oh yeah, there is an "intake orafice"... but we call it a
restrictor. So yeah, we're making 90hp through a 20mm hole. Not too shabby.
Side note: Most people don't realize about power and very light cars is that you never really end up making full power while driving anyhow. On the dyno the motor can load up and start producing power... in a car that just zips off, the motor never gets a chance to get loaded and make full power. Long story short, we've got a burly motor that is making competitive power."
We're really impressed by this program, and we have to say that we're jealous we didn't get to be involved in something like this in college, even if we were an English major. Hey, we coulda done the PR or something, maybe come up with a great slogan like "Formula SAE For You and Me!" (Feel free to use that guys. We won't charge you, as it's for educational use. Consider it our contribution.)
Related:
Cal Students Build Formula Car [Internal]