ITB Build Thread

Over the last few months i've been converting some Suzuki GSX-R throttle boddies to use on my 16v engine.

I'm a Mechanical Engineering student so I have access to a machine shop to make up all of the custom bits myself.



GSX-R Boddies straight off of the bike, 48mm at inlet and 42mm at the outlet, 90mm long. They are on 80mm centres so need to be split and spaced to the VW 16/20V 88mm port spacing.



Spacers turned up, the bolt that holds the boddies together wasnt long enougth so I used a length of stainless M6 studding. There is just an alloy strip along the bottom, so I made a new one drilled with the holes an extra 8mm appart.



However with the boddies spaced the throttles no longer reached so these had to be extended. I drilled and tapped the existing throttle arm and then bolted on a small peice of mild steel, this would probably have held it but I TIG welded it on in a few places aswell to make sure.



The throttle quadrant on the end was drilled out slightly to allow a mountain bike brake cable to fit. and am M5 capscrew and lock nut added to adjust the throttle closed position.

I bourght some 48mm Jenvey trumpets which matched perfectly to the intake of the throttle boddies. However there was no way of holding them on and I wanted to be able to change trumpets at a later date if i wanted. So I machined up some flanged that pressed over the end of the throttle boddy and are tack welded in place.



next was the manifold . I toyed with the idea of a CNC'ed flange but decided a cut down factory manifold was best. The runners are welded on at a slight angle and the cast flange had more material in it to allow this to be neatly blended.



The manifold was just cut off with an angle grinder and then set up on a milling machine with a fly cutter and skimmed to the correct angle.



The runner tubes had to be turned offcentre because the outlet of the throttle boddies were also off centre. Once they were turned up the samco hose joins them perfectly.

The other end of the runners had to be crushed to match the oval shape of the port in the flange, this was done using a press.

The manifold was them held together in a jig and the runners but welded to the cast flange.



Once welded it was internally ported using a die grinder and some flap wheels but not much material needed to be removed.

The whole manifold was then blast cleaned before being painted.



I was planning on using socks but was advised against this and instead got an ITG "megaflow sausage"



I didnt have enougth room to sandwhich the backplate between the throttle boddies and the trumpets so instead broke the trumpet from the flange and tack welded the backplate to the back of the trumpets.

The flanges were then refitted to the trumpets and tack welded on (Jenvey trumpets have a habbit of coming loose and rattling) so alot of engine builders do this anyway.



Fuel rail is just a standard 20v one with a few little custom made mounts.

The whole build has cost me 260, 130 of that is the airfilter and the backplate. However there is a hell of a lot of development work and machineing time which would not be cost effective if you were paying to have the parts made.

 

Great work there Ray. Makes mincemeat of big budgets, but also gives a chance of someone without the machines spending more time making one up also.

Twin injector set up potential also, unless I'm mistaken?

 

top job, very nice

 

Yum, yum, yum!

 

Nice work!

 

Looks great! A really clean engine install too!

 

Fantastic work Ray. Are you doing a uni project on this build too?

 

Wow very impressive.

 

Incredible work there mate, well done.

What management are you planning on running?

 

Looking good Ray

 

Thanks for the positive comments guys.


Yes Chris there is potential to run a second bank of injectors in the origional location but it's 2 close to the valve realy. If I needed another set for a 8500rpm+ engine the injectors would need to be in the trumpets to give the air and fuel time to mix.

It's going to be running on Omex 600 management.

 

Great work Ray, top job!

 

great job there mate wot management are u planning on using

 

Omex 600 as he said above Looks awesome ray as does the whole car build, won't be long now

 

oops should read the pages better only scanned em quickly when i wrote that

 

Nice work as always mate...your car's gonna be a monster!

 

quality job-fancy doing another set?!

 

Amazing work so far. Looks like you have done a quality job.

 

Thats a cracking piece of work, the engine looks as new.

Good Skills and thanks for sharing it.

 

Exactly! I used the peugeot sport forums many moons ago and the people on there are all w*nkers who only share things with them stupid enough to pay. They made me very unwelcome for saying so too