Bike throttle bodies

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maxiboy
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Bike throttle bodies

Post by maxiboy » Sun Jun 19, 2016 7:37 am

Been doing lots of research and it seems that there are claims of 20bhp to 30bhp on fitting individual throttle bodies to a 3.2 24v engine

45mm seems to be the preferred size.

I was thinking as the 24v already has the injector fitted all you really need is individual 45mm throttle plates and these could be salvaged from a few bikes..

I know the only real way forward is testing and it would require a lot of testing but in theory would there be any advantage in using the injectors in the bodies or would the ones closer to the head offer the best performance as if they did it would be a lot simpler to use those and just add bodies

Anyone have any real world experience or point me in the right direction please. thanks all
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Giuliettaevo2
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Re: Bike throttle bodies

Post by Giuliettaevo2 » Sun Jun 19, 2016 11:16 am

The original injector setup would be my preferred option.

They have the injector close and aimed at the valves at the correct angle.

Just fitting up a few tb's and blanking off their injector holes should do the trick.
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maxiboy
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Re: Bike throttle bodies

Post by maxiboy » Mon Jun 20, 2016 2:17 pm

found this

Where one injector is to be used per cylinder the best compromise position is immediately downstream of the butterfly. This gains maximum advantage from local turbulence and gives results surprisingly close to the optimum at both ends of the rev-range. This is the recommended position for most applications.
For performance at low RPM, economy and emissions the injector needs to be close to the valve and firing at the back of the valve head. This is the favoured position for production vehicles.
For higher RPM (very approximately 8,000+) the injector needs to be near the intake end of the induction tract to give adequate mixing time and opportunity. The higher the RPM, the further upstream the injector needs to be. As a result, use of speeds above approximately 11,000 RPM may give best results with the injector mounted outside the inlet tract altogether (see our remote injector mounting). It is common to fit both lower and upper injectors in such a system to cover starting and low RPM, as well as high speeds.
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SydneyJules
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Re: Bike throttle bodies

Post by SydneyJules » Tue Jun 21, 2016 7:09 pm

The Jenvey/AHM kit is 45mm- I've earmarked it for my 3.2. Mainly because it's proven.
I had wondered whether 45mm may be too big for a mostly stock-internal engine.
I asked Adie and he said they had made approx. 300 crank hp with the throttles and a Motec on a 3.2.
I'll obviously post my results up when the time comes.

When I was trying to figure out if I would keep my 12v and go big bore, I looked at bike throttles.

The best bits I could find were either the GSXR (pre-2008 from memory) or triumph speed triple throttles.
They both come apart and the GSXR ones have a linkage that can be spaced out.

From memory, the GSXR 750 ones are 40 or 42mm and have a single butterfly per barrel. The 1100 ones had a tricky second butterfly that was supposed to introduce localised turbulence to aid in charge mixing. It was vacuum controlled and I didn't think it would be worthwhile trying to get it to run.

Jenvey have bell cranks that you could modify to actuate both banks.

They also have multi-port vacuum banks so that you can get some vacuum for the booster and I have heard of guys running a map sensor off these pieces but I was always going to run it TPSvs RPM - which. Means no factory ecu.

The next issue was injector placement.
The Suzuki and triumph ones come with injector pockets and I had always planned to use them.
If the factory fuel rail didn't allow, then that was to be made for the injectors.
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You're not building a DTM race engine....
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maxiboy
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Re: Bike throttle bodies

Post by maxiboy » Wed Jun 22, 2016 11:02 am

thanks for the reply..

i have bought a set of 675 triple bodies cheap just to have a play with..

AHM remove the original injectors and i cant see the need for running two sets on a narrow rev band engine.. gains above 11000rpm lol

yes been looking at AHM set up and will try to replicate in for a whole lot less if i can..

if not i now they sell a decent set up.. cheers
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