Turbo teams, what is your goal?

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Originally posted by nowhere fast:

Turbocharging one of these engines might be one of the few cases in FSAE where the engine is producing greater power and torque than the standard bike. I wonder how well they would hold up to the higher cylinder pressures.

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Actually a seemingly large number of single cylinder teams make more power on their engine than it was stock. Pretty sure UAS Graz was at 90 hp, I think Wisconsin was close to that last year both with turbos, and we're near 60 hp N/A, and Ive heard that number from a few other teams.

Our engine is 35hp stock.

Most of the electric-start 450's come in a relatively conservative state of tune for the purpose of either meeting emissions or to better suit the matching vehicle despite the engine's shared architecture with a motocross bike. Yamaha used to advance the YFZ450 quad's exhaust cam an entire tooth from the YZ450f motocross bike's timing to help in derating in combination with a choked "pea-shooter" exhaust tip.

Many teams not running 600/4 sport bike engines exceed stock power naturally aspirated. On the high end, I've heard 78 hp from Erlangen's Aprilia and 82 hp from UM-Dearborn's Genesis 80fi (not a huge increase, but impressive nevertheless for a restricted 180 deg parallel twin).

Nathan,

You make a good point about availability likely being better in Australia. I had assumed that due to UTA's early 250 car and the heads on the Western Washington v8 that they were fairly common in the US as well.

There are a lot of them around south east asia. So it might suit some of the teams in that area.

Kev

Kev, the 250 4 cylinders aren't unheard of around here but the market is "flooded" with 600 four cylinders and dual sport 450 singles.

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Originally posted by Kevin Hayward:
Nathan,

You make a good point about availability likely being better in Australia. I had assumed that due to UTA's early 250 car and the heads on the Western Washington v8 that they were fairly common in the US as well.

There are a lot of them around south east asia. So it might suit some of the teams in that area.

Kev

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Not exactly. Dr. Woods told me he used to fly over to Japan and fill his suitcases with CBR250 parts, then fly back. I could have sworn that WWU's heads were off of something else, but you're probably right. The 4-cylinder CBR250 bikes and engines have always been grey market in the US, as they've never actually been sold over here. They're definitely an Asian and Australian oddity.

The WWU heads were indeed from a Kawasaki 250/4, but I'm not sure if source bike was any more popular in the US than the CBR250RR. I've heard that UTA was not at all pleased with the CBR250RR's reliability--a big issue when your parts supply is only as big as your professor's suitcase.

The easiest way to get the best engine is to make one. It's so easy I don't know why anyone doesn't do it... Just save all of your teams red bull cans and when you have 100lbs. or so (depends on how big it is) melt them down and pour into sand molds to make cylinders, head, and other etc. When the mold is done touch it up with some machining. If you have spare pistons, rods, valves, or etc. just design the engine so that they can be utilized. You'll invest in some custom ground camshafts if you have half a brain. Assemble everything and voila! You have a Super Optimized for Displacement and Oxygen Maximizing "Eco-recycled" Engine. or S.O.D.O.M.E.E. for short.

I've given away too much secrets already so you're on your own trying to figure out the transmission and crankshaft.

Turbo's are indeed not easy to justify.

I do believe though, that it might be easier to run a turbo, than design an intake (and exhaust) manifold correctly. As people said, it evens out pulses and it pretty much pushes air in the engine. It is more dangerous, as one can blow up an engine easier though. (I agree with almost everything else said)

There are not a lot, but a few options on turbo's, and i have seen one spool to 22-24psi MAP between 3500-4000RPMs.

You can run accel in one gear. you can also probably run endurance/autocross, with three. Removing the 3 gears from a gearbox, does save some weight.

You add weight, and packaging complexity. Some design aspects are easier. Low and mid range power can be much higher. But, one thing that is hard to do on turbo's is drivability. It does need tuning.

Running a turbo usually means also running lower lamda values at WOT, so worse fuel consumption. However a low boost, lean burn turbo, can be tuned for efficiency as well. Most importantly, a turbo can be efficient at low throttle position, and powerful at high. Gives the driver best out of both worlds.

To sum up:
Turbo +'s:
-More power before choke
-Less design effort in intake/exhaust tuning
-More options on engine tuning (power, fuel economy, drivability)
-More options on gearing

Turbo -'s:
-Packaging complexity
-Mistakes can easily kill an engine
-Tuning complexity - adds another thing to control - boost map
-Weight (Even though one can eliminate/undersize other components)
-Current rules with throttle body before the turbo.

So if i was to design a turbo engine for FSAE, my main goal would be to get the most out of the engine. Try to use fuel and air efficiently and at a rate that the DRIVER needs. (If my team's drivers cannot handle the power, it might as well not be on the car) However, for marketing it is a somewhat different story, as your target group is not your 4-5 drivers.

Excellent first post, Tinomik. Glad to have you around here.

Seems like lots of good posts here, so I'll keep mine short: with most comps still having a ~30% enduro finishing rate (of all teams entered), I would say reliability is pretty important. And I noticed a lot of cars failing to restart after the drive change (I'm going to assume engine could not restart, or dripping fluids are the main causes).

To me, the engine causes a lot of reliability issues, so by keeping it as simple as possible, you have more time to work on the other parts of the engine, that might otherwise cause you to DNF. Lots of teams talk reliability, but it appears that very few do. ACtually, this just reminded me of the number of times GFR (a winning team) has DNFed at comps...

For me: drivers and tyres/suspension make your car go fast; engines make your car unreliable.