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Wondering if it has been done?

Looking at welding a GTR plenum to RB20 runners and welding a boss on the front for the throttle body.

Had a search, couldn't find anything, has it been done? any opinions? (I know I'll get a lot, opinions are like assholes afterall :blink: )

Lastly, any good/bad experiences with china throttle bodies?

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https://www.sau.com.au/forums/topic/200787-modifying-gtr-plenum/
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i have seen adaptor plates, you are better off making some of them. you especially want to keep rb26 throttles, they are the only reason i would get a 26 plenum and go to all that effort.

you could also cut the flange off and put a rb20 one on. the inlet does not get as hot as the exhaust mani obviously but i would suggest you still need quiite a good welding hand

dont use a bigger throttle body on a forced induction car. Only thing you will get with a bigger throttle is the sensation of more power. Your standard rb20 throttle body is good enough to flow huge amounts of cfm on a turbo car. Your not sucking.. your focing so bigger wont do much at all. Id stick to standard cause of reliabilty

EDIT: I was speaking to plazmaman and they said they have seen drag cars with 1000kw+ with standard throttle bodys... the bloke talked to me out of buying one

Edited by choku_dori

I highly doubt you can make ~1300hp with the amount of airflow through a 63mm aperture.. someone do the maths and tell me it's true before I believe it.

rb26s13: what has been covered many times? there are two questions, a main and a secondary. Please be specific or piss off :thumbsup:

Lastly, I have an RB30DET in an R32 with a GT35R to go on (for those that don't know) so I don't care about response/power/etc, I need to do this as it is the only way the piping will work with my setup. I have seen the RIPS and plazmaman items, aswell as some custom jobs from people on the forums, but am reluctant to fork out for a new item at the prices they are.

Maybe I shouldn't have asked about the throttle body.. my mechanic said I can't use the RB26 throttlebodies (likely due to wiring etc) and TBH I really can't be assed trying to get them to work.

To cut it short, has anyone fitted an rb26 plenum to an rb20/25 (doesn't matter which as the required mods would be practically the same), with or without throttle bodies.

Is it safer than an ebay job from the states?

I have vaguely gathered that 26 plenums can run one cylinder slightly lean but as it's a widely known fact tuners compensate for it.. is this correct?

  • 1 year later...

wow.. forgot about this!

I'll get some photos next time I'm at the workshop. GTR plenum has been welded to RB20 runners, Q45 flange welded on but had to set it a fair bit further back than orginially imagined.. I'm running full GTR cooler setup so it's pretty damn tight for room. At the moment it looks like I'm going to have to weld a bend straight on to the throttlebody to get it tight enough.. maybe even lobster back it :action-smiley-069: heh

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