http://cgi.ebay.com/ebaymotors/Electric-Supercharger-Tu...dZ1QQsspagenameZWDVW

more info please, I'm intrigued on how those worked out, look a little more serious then those hair dryer electric superchargers ppl sell for 50 bucks on ebay

That is actually our listing for Cal Poly Pomona. We used it on our 2000 car and had some success with it. The system is a little heavy because we had to use a full size GM alternator to power it. From what the old team members tell me it was pretty easy to hook up.

hey DRTorkay since you seem to have some knowledge of charging fsae motors what boost do turboed fsae cars usually run. can you just get a regular car sized supercharger and run like 30psi to overcome the restriction. and i'm pissed some one beat me to the electric supercharger. i was thinking about it this year (unrelated)

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..like 30psi to overcome the restriction

Haha that is funny..overcome the restriction.

You can't just slap any old supercharger on it. Most Ford SVT superchargers (or most OEM applications) are way TOO big for a little 600 cc engine...and 30 pounds of boost....thats INSANE, that would destroy that little 600 cc engine. the SRT 4 runs a max of 25 pounds (with their stage 3 kit) and most supercharged applications (im talking big V8) run at most 10....and they are strong motors.

no offense but electric superchargers are not the best idea.....

Those are not just any superchargers, Turbodyne has alot of experience when it comes to boosting motorcycle engines.

When they ran the supercharger on the car in 2000 they put out about 75 rwhp and it had a nice flat torque curve, and that is really what helped the corner exits in the car. I don't understand what you mean but running a large turbo to overcome the restrictor. The performance would just be horrible. You can only suck so much air through a 20mm restricor. The whole idea of the electric supercharger was the make the whole forced induction aspect more efficent by using less power to make the same amount of boost.

I was told that electric superchargers were origionally intended for engines puting out 110ish HP. They also could not run them 100% continuously. We wired in a throttle switch to turn it on and off at about 80% throttle.

a little more info about it. the supercharger flowed enough air to maxout the restrictor at any rpm. this equated to about 75whp(measured on our engine-to-chassis dyno adapter)all the time depending on alternator load. I think max boost was around 10psi at 5000rpm which is also about where our motor idled(due to poor idle maping). the trick was that for short burst(~5secs) you could disable the alternator to free up an additional ~10hp depending on rpm. all in all it was a blast to drive and good enough to take a 600lb car to the top in the accel event.

"We wired in a throttle switch to turn it on and off at about 80% throttle."

Isn't that drive by wire and throttling after the restrictor?

well here's what i am thinking. any given engine can only flow so much air, naturally. superchargers increase the incoming air pressure (Have to add more fuel also) to make the engine seem to be bigger than it is and overcome the natural restricion of the engine. on an fsae engine i've heard that the restrictor makes the engine seem like a 250cc. so in turn you are using aprox half the fuel of a regular 600cc. so increase the incoming amount of air (the only way to do that because of the restrictor is supercharging) normal teams use (guessing) 12 psi and 60% of regular 600cc fuel flow. so increase the incoming air pressure and increase the fuel until you get back to that normal non restricted 600cc engine fuel flow. i don;t think i explained that real well but would that work? again right now i'm just talking about the flow theory, lets not get into manufacturing drive systems and computer controllers for the supercharger.

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Isn't that drive by wire and throttling after the restrictor?

no, it has nothing to do with the throttle body. you're simply turning the supercharger/alternator or or off.

Forced induction does not change the amount of air coming through the restrictor. Once the restrictor is maxed out, there is nothing you can do about it.

What forced induction does is keep the restrictor maxed out at times when the motor wouldn't be doing that on its own, like low rpm or between intake strokes. You get a wider power band, not a taller one- for the most part.

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Originally posted by kozak:
well here's what i am thinking. any given engine can only flow so much air, naturally. superchargers increase the incoming air pressure (Have to add more fuel also) to make the engine seem to be bigger than it is and overcome the natural restricion of the engine. on an fsae engine i've heard that the restrictor makes the engine seem like a 250cc. so in turn you are using aprox half the fuel of a regular 600cc. so increase the incoming amount of air (the only way to do that because of the restrictor is supercharging) normal teams use (guessing) 12 psi and 60% of regular 600cc fuel flow. so increase the incoming air pressure and increase the fuel until you get back to that normal non restricted 600cc engine fuel flow. i don;t think i explained that real well but would that work? again right now i'm just talking about the flow theory, lets not get into manufacturing drive systems and computer controllers for the supercharger.

It sounds like you are saying that with a supercharger, you could just cram in as much air through the restricter as would flow in an unrestriced motor. While this would be nice, it is not the case.

I would be cautious about the rules implications of running an electric supercharger. The rules outlaw hybrid powertrains that store energy, although I am not sure about the exact wording. I would consider an electric supercharger system, where energy is stored up and then delivered to the compressor when the driver demands power, to violate the intent of this rule. If the alternator were driven directly off the crankshaft and powered the compressor through a separate circuit, with nowhere for energy to be stored (like a battery), I would imagine it would be OK.

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Originally posted by kozak:
well here's what i am thinking. any given engine can only flow so much air, naturally. superchargers increase the incoming air pressure (Have to add more fuel also) to make the engine seem to be bigger than it is and overcome the natural restricion of the engine. on an fsae engine i've heard that the restrictor makes the engine seem like a 250cc. so in turn you are using aprox half the fuel of a regular 600cc. so increase the incoming amount of air (the only way to do that because of the restrictor is supercharging) normal teams use (guessing) 12 psi and 60% of regular 600cc fuel flow. so increase the incoming air pressure and increase the fuel until you get back to that normal non restricted 600cc engine fuel flow. i don;t think i explained that real well but would that work? again right now i'm just talking about the flow theory, lets not get into manufacturing drive systems and computer controllers for the supercharger.

Any modern naturally aspirated 600cc four-cylinder motorcycle engine can choke the restrictor and reach maximum power. Therefore, any sort of forced induction system will not increase the engine's peak power output, only make its power band wider (choke the restrictor at a lower RPM).

I think a turbo is most likely a better solution, as turbos do not require electric power. Especially with a wastegate that opens when the restrictor is choked.

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Any modern naturally aspirated 600cc four-cylinder motorcycle engine can choke the restrictor and reach maximum power. Therefore, any sort of forced induction system will not increase the engine's peak power output, only make its power band wider (choke the restrictor at a lower RPM).

Really? Can you guys make 95hp without the turbo? The higher NA numbers I've seen are 75 hp or so. Not to mention torque, I have not seen a NA go over 45 ft lbs, I think I've seen about 65 from Cornell, which is a sure sign of more air going into the motor. So, either the turbo DOES move more air past the restrictor, or your cheating .

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It sounds like you are saying that with a supercharger, you could just cram in as much air through the restricter as would flow in an unrestriced motor. While this would be nice, it is not the case.

not what we're saying at all. what we are saying is that it will pull as much air through the restrictor as will flow through the restrictor.

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I think a turbo is most likely a better solution, as turbos do not require electric power. Especially with a wastegate that opens when the restrictor is choked.

turbos have to spool, electrics don't. also,we never said that the torque curve was flat. it makes a lot of torque very low in the rpm band and it continually decreases as rpm's pick up, which equates to a relatively flat HP curve. NA motors have a tough time developing torque at low rpms due to poor VE, forced induction makes a big difference here be it turbo, supercharger, or electric supercharger.

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Really? Can you guys make 95hp without the turbo? The higher NA numbers I've seen are 75 hp or so. Not to mention torque, I have not seen a NA go over 45 ft lbs, I think I've seen about 65 from Cornell, which is a sure sign of more air going into the motor. So, either the turbo DOES move more air past the restrictor, or your cheating .

in my opinion the real difference is they're using an engine dyno to measure their hp so the drivetrain losses aren't taken into account. if you put an NA motor on an engine dyno i'm quite certain there are many teams that would make 95hp too. I mean look what happened when they chassis dyno'd their car at detroit in 04, they made 75ish hp. I'm not trying to start any pissing contests here. i'm sure they make a lot of power, i'm just reiterating the fact that dyno numbers aren't the end all be all.

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Originally posted by DaveC:
I think a turbo is most likely a better solution, as turbos do not require electric power. Especially with a wastegate that opens when the restrictor is choked.

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Any modern naturally aspirated 600cc four-cylinder motorcycle engine can choke the restrictor and reach maximum power. Therefore, any sort of forced induction system will not increase the engine's peak power output, only make its power band wider (choke the restrictor at a lower RPM).

Really? Can you guys make 95hp without the turbo? The higher NA numbers I've seen are 75 hp or so. Not to mention torque, I have not seen a NA go over 45 ft lbs, I think I've seen about 65 from Cornell, which is a sure sign of more air going into the motor. So, either the turbo DOES move more air past the restrictor, or your cheating .

My original post was basically a first-order approximation for the behavior of the engine/restrictor combination. You are absolutely correct that there are many more complicated effects going on. I was just making the point that putting a turbo on an FSAE car isn't like putting a turbo on your average street car - you can't expect a 50%+ jump in peak power.

But, to answer your question: yes, if you simply pulled the turbo off our engine, or held the wastegate open, the peak power would be less. There are many reasons for this, most of which I won't go into. But mainly, our overall powertrain is the result of years of evolutionary development, and the whole engine package is designed to work with the turbo. It wouldn't be a fair comparison, so to speak. As an example: our engine (the block) is actually one of the lowest-performance sport bike engines currently in production. We use it because it's a good match for the turbo. But, if we wanted to run naturally aspirated, we would most likely want a different engine.

With regard to torque, our higher torque peak is an indication that we're moving more air past the restrictor at low RPM, when a NA motor at the same speed wouldn't be choking it. Torque is proportional to cylinder pressure, so when we're on boost, our torque will be higher than a NA engine. This goes back to the wider powerband.

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in my opinion the real difference is they're using an engine dyno to measure their hp so the drivetrain losses aren't taken into account.

Got me, I wasnt thinking about that. But, the torque numbers are directly related to airflow, 65 vs 45 ft lb is more drivetrain loss than might be expected. BTW, the "or your cheating" was a joke, just to be clear... What were your torque numbers with the electric?

Spool is an issue, but having owned turbo cars (AWD Talon) for over 10 yrs, you learn to deal, but it does bother a lot of people who arnt used to it.