Stock Engine Intake Manifold

[Robert Hopkins]

Hello,

I'm a member of the University of Delaware Powertrain team. This year we have started using a GSXR600 motor and we are planning on using the stock intake manifold for the motor. The stock intake manifold has a throttle body for each of the 4 runners into the engine.

Do we have to take the butterflies out or can we leave them in at constant position?

If other teams have not has any experiences with this issue. I will send the rules committee another email, but the last time I sent them an email it took a month for a response.
We will be tuning our engine sooner then that.

I figured I'd ask if other teams have been forced to remove the butterfly at competition or have seized them in one position and been fine at inspection.

Thanks,
Robert

[Fantomas]

Originally posted by Robert Hopkins:
Hello,

I'm a member of the University of Delaware Powertrain team. This year we have started using a GSXR600 motor and we are planning on using the stock intake manifold for the motor. The stock intake manifold has a throttle body for each of the 4 runners into the engine.

Do we have to take the butterflies out or can we leave them in at constant position?

If other teams have not has any experiences with this issue. I will send the rules committee another email, but the last time I sent them an email it took a month for a response.
The company tuning our engine needs to know as soon as possible.

I figured I'd ask if other teams have been forced to remove the butterfly at competition or have seized them in one position and been fine at inspection.

Thanks,
Robert

Well,
you are already deep into trouble due to A6.1 and A6.3

I can only remember one or two teams that ever used the stock intake manifold and none of them was in any way successful with it.

Fantomas

[Robert Hopkins]

Let me clarify a bit.

We have designed and constructed an air box based on competition rules. The air box interfaces with the engine thru a set of runners (an intake manifold) into the engine. The air box is designed to interface with the intake runners that came with the motor.

We are not using a stock airbox from a GXSR600.

Robert

[TMichaels]

I think the bigger concern that Fantomas has and that I agree to is, that according to FSAE Rules A6.1 and A6.3 you are not allowed to let a company do the tuning of your engine.

However, the stock runners are tuned for peak power at high rpms where the restrictor is already choking. Thus it usually is not a good choice to use them anyway.

[Robert Hopkins]

Let me clarify again

We will plan to tune our engine on a dyno at a company who has offered us the use of their dyno. We do not have a dyno. They will give advice on tuning to us as we tune as none of us have experience tuning. Sorry for the bad wording.

I will change the sentence in my original post to avoid confusion about who is doing the tuning.

We will definitely consider redesigning the runners next year. We have been waiting on Ricardo Wave Software to help redesign the runners. Hopefully we can use Ricardo for next year's car.

Thanks,
Robert

[Kirk Feldkamp]

We used the stock throttle bodies (in a gutted form) on our GSXR600 engines for a number of years. You could leave the throttle blades in there, but I recommend you take both the blades and the shaft out. If you pull all of the bodies apart, you can then plug the shaft holes pretty easily... and then reassemble the bodies back together. It's advisable to run a simple tap of a proper-ish size through the holes vacated by the shaft, and then fill the holes with JB Weld or similar epoxy. If you don't do the tap operation, the engine will suck the plugs into the engine. No bueno. Trust me, I've done it. http://fsae.com/groupee_common/emoticons/icon_wink.gif

-Kirk

[Michael Royce]

Robert,
By all means, send in your question to the Rules Committee for an official answer.

But in the past, the answer to your question has been that you have to remove the butterflies and shafts from the stock throttle bodies and plug all the holes. (Then add the new plenum and throttle body.)

If your engine has those rubber couplings between the cylinder head and the throttle bodies, you will need to add brackets to span the couplings to meet IC12.4.3.

[Racer-X]

You aren't allowed to have throttles after the restrictor and you aren't supposed to have someone "design" your intake for you. If you can make your car meet the first requirement you could probably get away with running the stock intake with your own airbox with resrictor. The stock intake though is going to have poor throttle response and be tuned for high end power so it won't drive very well.

[Dash]

we have run the stock ones before. Just pull all the shafts out, turn down a few aluminum plugs, and weld them in. Its really a decent way to attach the plenum to the motor and keep using the stock fuel rail/injectors. Just watch for air leaks at the mating surface between the stock housing and your plenum.