throttle bodies on the cheap

Level 7 User Joined: 27 Feb 2004 Posts: 243

ok, ive been doing some research into the use of motor bike TB's on car engines. msot notably, vw, and honda lumps. theyve managed to do this quite cheaply, so ive decided to give it a go. i can source a set of gsxr 750 throttle bodies for about 55quid second hand. these have either 40 or 42mm throttle plates, which should be ideal for the 2litre beast, to keep the thing tractable from low revs. these run multipoint injection as standard.

my plan is to ditch the injectors on the TB's and run the standard f7 setup, injectors located in the head. i wanna use all the sensors on the f7 as they are, TPS, map, ISCV, etc. buy doing that, it should enable me to get it running, then get it properly mapped using a piggy back ECU, like a unichip.

the only problems i can forsee are fabricating the inlet manifold, trying to create oval runners near the head, and determining the runner length for optimum power. has any1 (i.e. chris h) got any pointers, etc.

all the fabrication work will be handled my jonboy and myself (even tho he dusnt no it yet!!LOL)

jimbo

Level 7 User Joined: 27 Feb 2004 Posts: 243

heres a link to a TB project on a integra type r lump;

http://homemadeturbo.com/tech_projects/itb/index.html

Forum Moderator Joined: 16 Feb 2004 Posts: 1356

I leave any of my half arse technical comments at the door and wait for Chris... gotta sound nice though!

But gotta post this...

Cheers for the link!

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

I was looking for bike TB's not long ago to do this. Bastard you stole my idea!

Anyhoo,

Start with manifold. Some people have gone the super high tech way, used a head and TB flange and then connect them with silicone hose (really) and for those that fine the hose collapsing tape on the outside and a spring on the inside.

I think this should be avoided but its an option to get the thing up and running whilst a manifold is made.

Using the injectors in the head is a good idea, this means the thign will run ok at low revs, however if you want silly power or even turbo it etc at a later date you can bring the TB's injectors in as well. You probably won't have a need for it though.

TPS yes, CTS yes, MAP yes, CAS should be ok, ISCV erm no chance matey. Only way you could use that is if you run a plenum which means no TB's.

Inlet manifold, this is actually easy enough if you can weld. All you need is the 2 flanges, how do you get that I hear you cry with tears rolling down your cheek, get a set of gaskets and then use steel plate as a flange, 6-8mm plate is ideal, strong, won't warp or crack. Exhausts need a good 10mm.

Cut the flanges out then its a case of adding a pipe inbetween to join em. Get round pipe to match the TB's, then its a case of finding somewhere that can flatten and stretch it into the oval for the head. Some old exhaust shops have various dollies that may be useful for this.

Length, hmm tricky one, basically get it make the manifold try to get a decent length on the manifold runners, not just 1 inch direct studs, a good 4 inches then you have to worry about the trumpets.

It really depends where you want the power.

Oh yeah link doesn't work for me!

Forum Moderator Joined: 16 Feb 2004 Posts: 1356

Try the link I put up in the Club Links thread Chris

Level 7 User Joined: 27 Feb 2004 Posts: 243

i was thinking of running the ISCV to all 4 runners, using t pieces. ive seen it done before on other TB setups.

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

yes you can do it by feeding into the TB's injector bosses, but tbh its crap.

I would just do it properly.

They don't tend to have toruble with stalling etc Well the properly set up ones don't, even when you turn everything on and turn the steering.

But if you want do it.

Level 7 User Joined: 27 Feb 2004 Posts: 243

so if i ditch the ISCV, then i wont be able to run standard ECU then?

Forum Moderator Joined: 16 Feb 2004 Posts: 1356

Surely you would want to get it mapped with some sort of 3rd party chip to get the most out of it any?

Level 7 User Joined: 27 Feb 2004 Posts: 243

yeah, but my plan is to use the standard managment system as a base, then use a piggy back ECU like a unichip to control the fuelling and stuff. dont wanna rip out the ECU and loom, and spend a shed load on summat new. if i can get away with running current setup then i will! lol

jimbo

Forum Moderator Joined: 16 Feb 2004 Posts: 1356

Fair enough, good point!

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

no you won't be able to use the ren ECU to drive that lot. Well you could but your as well going to a decent ECU.

Site Subscriber Joined: 22 Mar 2004 Posts: 150

there was a clio on ebay with r1 carbs on, thet had to cut a hole through the bonnet it looked a basterd hope you aint got to do that with the 19.

Forum Moderator Joined: 16 Feb 2004 Posts: 1356

Yeah I saw that one a while ago... was posted on another forum. Went for 3500 or somethin like that!

Level 7 User Joined: 27 Feb 2004 Posts: 243

yeah that was a bodge job. was a carb jobbie, not fuel injected TB. this will be done properly, lol

jimbo

Mr Quoter-vator Joined: 16 Feb 2004 Posts: 7405

lol nice to find out im involved in a project that i dont even know about LOL

so if it was all set up with the std sensers, why couldnt u use the std ECU?? surely if its all used like that we are just (in simple terms) changin the shape of the inlet. all sensers still sense the same as before...throttle cable still opens a plate...

Forum Moderator Joined: 16 Feb 2004 Posts: 1356

Throttle bodies are just that, plural. You have four manifolds.. which is the reason why you can't use the ICV, even if you branch it off to the four bodies... for it to run right you need it mapped properly because it is probably outside of what the standard ECU could cope with.

Mr Quoter-vator Joined: 16 Feb 2004 Posts: 7405

but how? ...end of day still just air goin into the ports...not more air or forced air?

Forum Moderator Joined: 16 Feb 2004 Posts: 1356

Yes but each throttle body is going to be diiferent from one another, the valver manifold has the runners all coming off the one manifold.. so the ICV pulses the air for the one manifold... it will cock things up if you try and use the one ICV for four separate manifolds. Throttle bodies do provide more air. Whether or not the air is faster I don't know due to the shape or the inlet on the valver manifold in comparison to the relatively straight throttle body manifold that would need to be fabricated.

Mr Quoter-vator Joined: 16 Feb 2004 Posts: 7405

soooo....how do people get round this problem? how do u replace the ISCV?

Forum Moderator Joined: 16 Feb 2004 Posts: 1356

You don't use one