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Need advice on choosing manifold - rb26/30 single turbo GTX4202R

dorifticon

By dorifticon,
in Engines & Forced Induction

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dorifticon Community Regular

dorifticon

Posted
Posted (edited)

Need advice on choosing manifold - rb26/30 single turbo GTX4202R

Hi all

I'm currently in the process of dummying up the fitment of my garrett GTX4202R on my rb26/30 and of course running into some fitment issues.

1) First issue is the clearance between the turbo and the block - the compressor housing fouls against the rocker cover by maybe 1-2 mm. Might be able to either relieve the rocker cover or offset grind the cylinder head flange by 1mm or so to angle it out slightly. EDIT: or does anyone make an exhaust manifold insulator/spacer? even 3-5 mm would probably do it.

2) second issue is more difficult. the manifold seems to sit the (admittedly huge) turbo too high in the bay to shut the bonnet. This is probably not assisted by the fact that I already have an extra 38mm of deck height due to running the rb30 block.  But it's so close I won't really know until I dummy it up.

It's a nicely designed mx motorsports steampipe manifold with a nice collector and having done some measurements with a spare block, it's going to be a game of millimeters. But just want to know if there are any manifolds which sit the turbo nice and low in the engine bay, while still clearing the a/c - I would prefer to just buy something ready made and minimise the amount of screwing around if possible, in the event it comes to having to buy a new manifold.

any suggestions gratefully appreciated. Oh, needs to be twin-scroll T4 flange, and if possible twin 38mm v-band gates.  Or, custom. Some that I've seen also angle the turbo out sightly so the intake is looking more to the passenger-side headlight.

Cheers

Andrew

Edited by dorifticon
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Old man 32 GTR Proficient

Old man 32 GTR

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Posted

Goodluck with it, I'll be dummy fitting my 68/70, hopefully in the next couple of days. I measured what I can and I'm in the same boat as you, I think it's going to be a game of mm! Mines a 26/30 as well so always fighting for mm when it comes to under bonnet clearance lol

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reaper Experienced

reaper

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6 boost make a 26/30 specific manifold that clears everything and has good clearance for bigger turbos. I am running one of their manifolds in twinscroll t4 albiet with a single 60mm gate just to help with space however the 6870 clears no worries. Motor is a 3.2 sitting on standard mounts with crossmember in standard position.

18738796_1686579274702768_8125430541312686809_o.jpg

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  • 3 weeks later...
Old man 32 GTR Proficient

Old man 32 GTR

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Posted

Hi dorifticon, manifold is a custom job for a guy who works out of the JEM workshop.

I'm running a single precession wastegate that came with the turbo .

Bonnet mods, just needs a small section of the ribbing removed. The bonnet actually closes but is raised about 5mm on the turbo side, obviously from hitting the turbo, the ribbing is about 30mm at that point and hits the cold side of the turbo so once cut should be all good. I've also had the manifold and turbo ceramic coated to help deal with the heat

 

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SiR_RB Grand Master

SiR_RB

Posted
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I had the same issue

ordered a "gt42" 6 boost manifold for my r32 gtr 2.8 stroker and my 7175 didn't clear by miles

got sent another one which didn't clear either

ended up buying a custom made turbo1 manifold with twin external 38mm wastegates

turbo sits perfect now between turbo and bonnet, turbo and strut tower and most importantly clears AC lines 

IMG_2409.JPG.9de493b52fdf6c8f041c479fc1abeed3.JPG

IMG_2319.thumb.JPG.2f7c93bbbe35e6fe43fedde71d8bc4ed.JPG

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Old man 32 GTR Proficient

Old man 32 GTR

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Posted

Oh yes that was the other part of the question, yes I have AC and it cleared the lines by a mile.
Didn't quite clear the bonnet but it was made for an r34 with an rb26 not a 32 with a 30/26.
And since the bonnet has already been slightly modded for engine clearance I'm not fussed in cutting it a little more

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