# 16v ITB Build Diary



## dub_nutta (Dec 6, 2006)

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.


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## VWralley (Mar 30, 2002)

*Re: 16v ITB Build Diary (dub_nutta)*

awesome work man! i did mine the exact same way but i dont have access to cool machining tools to make it look all sweet like yours








any chance you'd like to sell me a set of the trumpet holders?


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## Muffler Bearing (Apr 4, 2004)

could you estimate the angle that you cut the manifold? i am in the middle of doing something almost identical but am having a hard time translating the angle at which i hold the throttles to what it ends up being when i bring it to work and cut it.
-j


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## wobvintage3 (Jun 10, 2005)

*Re: 16v ITB Build Diary (dub_nutta)*

You just have to machine more of the trumphet plates.. I think you could make them for $20 or so, and sell them for $65, or $75. The manifold is also nice, but it has other obsticles. If you do make the flanges I am in.. If you arent going to send us the cad


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## d_maccon (Jun 14, 2006)

In the manifold you cut down did you just plug the holes with something or what? for the 
CIS-E injectors I mean.


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## dub_nutta (Dec 6, 2006)

Injector holes are pulges with a little disc held in place with a G60 injector seat.
The angle of the manifold is a difference in 10mm between the top and bottom of the port, which rougthly translates to 17 degrees


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## Muffler Bearing (Apr 4, 2004)

thanks!
i want to make sure i have it right the second time, i already cut it once at the wrong angle. and using a 5/8" end mill sucks when you have to go back and forth over it so many times... we dont have a fly cutter here








-j


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## VWralley (Mar 30, 2002)

*Re: (Muffler Bearing)*

sawzall http://****************.com/smile/emthup.gif


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## Muffler Bearing (Apr 4, 2004)

band saw








-j


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## Fast929 (Nov 13, 2004)

*Re: (Muffler Bearing)*

Looks great man! Excellent job http://****************.com/smile/emthup.gif


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## skidplate (May 4, 2004)

That looks so nice. I hope I can get the guys in the machine shop side of work make me the spacer bits for mine.


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## slappynuts (Feb 27, 2005)

*Re: (skidplate)*

I have been through this exact build so if you have any questions just ask.
I found it easier to weld the injector holes in the stock manifold shut.I also bent the two outer intake runners in to match up with the TBs.


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## Wishing on a Vr (Feb 7, 2003)

*Re: (slappynuts)*

how would one go about doing this for a vr6


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## XwalkerX (Apr 7, 2002)

*Re: (Wishing on a Vr)*

amazing i cant wait to get my project itb started







http://****************.com/smile/emthup.gif


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## tstmstr (May 8, 2006)

*Re: (XwalkerX)*


_Quote, originally posted by *XwalkerX* »_amazing i cant wait to get my project itb started







http://****************.com/smile/emthup.gif 

X2 http://****************.com/smile/emthup.gif


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## Rocco Fella (Jan 20, 2007)

I give you guys crazy credit...that looks sick...


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## WolfGTI (Jun 16, 1999)

*Re: 16v ITB Build Diary (dub_nutta)*

Nice work - FYI - Velocity stacks / airhorns need a minimum of 19mm in front of them to be effective, this is from Jenvey themselves, having the filter press right up against the bellmouth negates any effect they have on smoothing air entering the runner.


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## impulse byer (Mar 8, 2003)

*Re: 16v ITB Build Diary (WolfGTI)*









ABF alternator set up?


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