Using GSXR 750 Bike Throttle Bodies for ITB setup? Photos inside

[sniper]

Hey everyone,

I just bought a pair of Suzuki 750 throttle bodies in hopes of using them on my 1UZFE as an Individual Throttle body setup. Here are some photos, they are ~49mm on the outside and 42mm on the inside. I picked up both of these for a total of $122 shipped to my door for both. Think they are usable? They look quite small when on the engine, anyhow, here are the pix -

Top, or front of them

Bottom, or backside

This is where the stock injectors go

I bought a pair of ITBs that had a second set of butterflies towards the front of them, here you can see the shaft that used to hold a butterfly, only thing i can think of is these flaps were part of a traction control system, i removed all of these parts

They look tiny....

Too small? As for the spacing between each throttle body, you can pull this entire setup part and space them as you like, but you will then have to redesign the linkage between each throttle body


Here are some photos of the 750 bodies next to GSXR 1300 Busa bodies, they are the same inner size.

Busa is on the left, 750 on the right

busa left, 750 on the right

back sides of both, 750 on top, busa on the bottom

The actual flaps on the busa ITBs are bigger because they are in the center where as the 750s are towards the bottom because there used to be a second set of flaps towards the top for traction control or whatever it was.

So, thoughts, ideas?

 

[JustenGT8]

Looks quite neat but as you say they are a little closely spaced so the manifold adaptor might have so sharp bends in it? 42mm ID is on the small side but should give snappy response on a mild engine.

 

[cribbj]

Sniper, I had thought to use these for my V12 project, but decided against it because 1) the fuel rails would have remained outboard, and aesthetically I didn't think it looked good, and 2) I decided to change the configuration from having them sitting in a cross-ram horizontal configuration to vertical, and there simply wasn't enough room in the 60 degree Vee for all the hardware, and 3) At the end of the day, with all the modifications and custom manifolding that needed to be built, there wasn't a big cost advantage in using them, over commercially available ITB's.

I still think these bike throttles would be a lot of fun to use for an application. You can't beat the price and the Honda boys and Locost builders have been using them for years for their cars. I've still got half a dozen sets of these GSXR TB's in my workshop; maybe they'll find a home on a project one of these days.

Here's a nice looking horizontal setup that is similar to what I was going to do:

 

[rms]

They should be fine for max torque around 5500/6000, if you are looking for max torque around 7/7500 they will be a bit small.

I am building a customers engine with 8 - 42mm Toyota 4age ITB's.

Spacing 3 t/b's at 105mm, with the end one at 95mm will minimise the angle to the ports.
I would block the original injector point, and place the injectors at the port. Keep the butterfly as far from the head as possible to minimise disturbance at the port.

Go for it !!

 

[cribbj]

Here's a couple good pics showing the spacers and tab extensions that you'll need. I think this set went on a Zetec motor in the UK.

I've got some dimensional info somewhere on all the versions of the GSXR TB's. If you're interested I'll try to scare it up & post it.

Here's a great link showing most of the common motorcycle TB's: http://www.msefi.com/viewtopic.php?t=6627

 

[autronic]

cribbj:

That setup looks great ! The biggest problem thou, is still an intake manifold to suit.

 

[striker]

Hey Cribjj,

True about the zetec thing, I can't link piccies of Locostbuilders.co.uk because you must be logged in, but that's the one.

there's countless people that have used these on zetecs and 4age's in kitcarcountry, anything has been done upto 200+hp on 2 liter ford zetec engines, remember most carb venturi's are much smaller than the complete bore of these ITB's. Erol has a good point on spacing and angle.

I know most of the UK crowd make small adaptors that fit to a DCOE manifold that they can buy for next to nothing at Burton etc etc,
so they dont make the complete manifold, the just make adaptors that bolt to a weber manifold on one end and takes the original carbmount rubbers on the other side. see attachment.
that one was made using nothing other than 1 good file and 3 sizes of holesaws and lots of elbow grease.

all of them use the TB mounted injector, and block the head injector port.

Bauke a friend of mine uses R1 ITB's on a honda D16 engine in his mojo, still needs good mapping but certainly has some potential.

Grtz Thomas

PS MV agusta F4 1000cc magnetti ones are almost perfect for a 1uzfe. I have a set which can go to a good home, so if you find another, you'd have 8 x 45mm ITBS with Pico's

 

[LondonBenji]

As a side note the second butterflys I don't believe is anything to do with traction control, its to do with getting fuel injection working right (smooth) on bikes because from what I understand it has never been easy on bikes as it has been on cars, though I can double check this tomorrow.

 

[striker]

true, suzuki started this in production MC engines for torque controll, but not to solve traction problems, it was to produce beter usable torque on lower rpms on full throttle Low rpm situations, it seems to work for them, but would be a nightmare to set up for a different engine if at all possible with good effect.

the normal treat is to take them out and bin them.

Grtz Thomas

 

[capn]

You know ironically I have been doing the same thing, except mine is all 1's and 0's and I haven't had any time for my side project