Hi there,

So, anyone with experience of gsxr600 throttle body trumpets and boost?

My plan is to support the plenum (pulsar GTiR) relative to the engine, so this will handle the force of the airbox away from the throttle bodies (this is standard technique that folk use when boosting motorbike engines). Without this I think the plenum would just pull the trumpets off the throttle bodies, but strapping it holds everything together.

Then the gsxr600 trumpets would be mounted into a hole in the back of the inlet plenum in the normal fashion, using the slot in the trumpet to seal. This is standard practice on normally aspirated engines. My thinking is that when boost comes on it would tend to improve the sealing of the rubber to the plenum back plane so it should work.

This is appealing to me, because of the costs involved (none), and the fact that I can do it tonight in the shed. Otherwise I will have to get some new trumpets made up, which I would bond to the plenum back plane, and then couple these to the TBI's using hose and a pair of jubilee clips. Getting new trumpets made sounds expensive.

Probably running up to 10psi.

Any thoughts?

Matt

I have to wonder if the aggravation of individual throttle bodies is worth it on a forced induction application. How are you going to determine engine load?

What you are suggesting should work ok though, with the plenum securely attached to the cylinder head there is no net force acting on the throttle bodies trying to pull it out of the fittings, so as long as the rubber parts are strong enough to hold the boost in at typical underbonnet temperatures you should be ok.

[Edited on 18/1/11 by MikeRJ]

I wonder too.

ITB's supposedly improve off boost performance according to the old-skool suzuki turbo nutters. Its fairly common on high performance stuff. The mechanics of it isn't difficult as it is easier for me to do this that the single throttle body thing.
I'm glad you think it might work, and that I explained it adequately. There is only about a 4mm annulus of the rubber that will feel the boost, so the forces are fairly minimal.

You are right tuning is potentially a worry. I was going to go with long runners, tame cam, and then go speed density. I posted something on the MS forum and that was the recommended first port of call. I have MS2 and get a very stable MAP signal so maybe it will work. There are a few options on the tuning (Flak has been down this route although he had more invested so was necessarily more cautious than I will be ). It should be tunable because various street cars do it, but maybe just require some programming.

Matt