Anyone Using Single Gt4088r?

[Chris Wilson]

Considering a GT4088R single on my 2.6 engine with Tomei 280 degree cams and mild head job, all steel / forged internals and 8.5 to 1 CR, on Motec management, stock type GTR intake and plenum. Would one of this family be a good choice? A/R size recommendations? Car is R33 GTS-t for track day use only, with some weight reduction carried out. Thanks

Edited May 26, 2006 by Chris Wilson

[2rismo]

0.85 rear would prob be best.

[The Mafia]

yeah, go for the smaller .86 rear for good power but half decent delivery.

[discopotato03]

A GT4088R on an RB26 is getting fairly big for a tarmac racer , what sort of power are you looking for and where do you want it to go from rpm wise ?

There is a wild cat hybrid (non Garret conversion) of the GT4088R cartridge called GT4067R that uses the TO4Z's compressor wheel (TO4R wheel) instead of the 88mm C117 wheel . The TO4R wheel is supposed to max out at from memory 75lbs air and the C117 about 68lbs .

The TO4R wheel is ~ 84mm OD (63Trim) and is usually found in .70 or .80AR TO4S comp covers . The C117 wheel is ~ 88mm (52T) and comes in the .72AR GT40 cover .

Its difficult without back to back testing to know if the TO4Z has enough capacity to cover most of what a 4067R or 4088R can do particularly with HKS's optomised housings . Cost wise the generic Garrett TO4Z works out a lot cheaper and the HKS exhaust housings are available if needed . I think Datsquick once said that 700 odd Hp is not difficult to get from the Garrett marketed TO4Z and I'd reckon response would very likely be better than a GT4088R . Geoff Raicer tells me that the 4088R is not a turbo that likes to be toned back with small AR housings as this kills a lot of its potential . A TO4Z with mid-large sized TO4 turbine housings may be a better thing .

Food for thought cheers A .

[Chris Wilson]

A GT4088R on an RB26 is getting fairly big for a tarmac racer , what sort of power are you looking for and where do you want it to go from rpm wise ?

Fabulously detailed reply snipped a bit. Thanks for such a helpful response, your turbo knowledge astounds me, do you work for Garrett or something?

I want to avoid HKS hybrids for the simple reason I want to be able to have the turbo made and rebuilt locally, here in the UK, and to know repairs and mods don't mean a long wait or shipping from Japan. As such I am limited to off the shelf Garrett housings and listings.

I'd like the spool to become noticeable from about 4500 RPM max. Full boost by 6250 or so, with a rev limit of 8800 max. I don't mind playing with housings so long as they are straight swap, I don't really want to be fabbing new downpipes and stuff to run a different turbine housing. Manifold will initially be a new HKS cast iron, split TO4, remote wastegate one. If that cracks, or I feel it's a limitaion to performance, I'll go tubular, but as I have this, plus a used spare, I'll try it initially.

As an aside I have come upon a new GT3040R for my 2.5 DETT engine, which shares the same shell as the RB26 engine will, again to go on an HKS cast manifold, this one the RB25, TO3 bolt patterns type. This engine has mild Apexi hydraulic cams (not sure of spec, they were in the engine when i imported the car). Bottom end is stock, save for rod bolts and a 1.8mm head gasket, ECU is Power FC, RX-7 FD 550cc injectors, bigger fuel pump, bigger AFM on stock intake system. Currently running an Apexi RX-6 IHI turbo. Compressor has 82 mm major, 48 mm inducer, A/R is 0.98 Would you care to suggest how the GT3040R family will compare? The Apexi manifold has cracked, so a manifold change really needs a turbo change, because of the unusual IHI flange pattern, hence the Garrett 3040...

Cheers, I have been searching on your posts, a mine of info, but a lot of it is a bit over my head Thanks again.

Edited May 26, 2006 by Chris Wilson

[discopotato03]

I'm not sure of how a GT3040R would compare to the Apexi RS6 .

I can say that the GT3040R is a weird Garrett hybrid of GT30 turbine and the smaller of the two GT40 series compressors ie 82mm (larger is 88mm) .

Depending on your point of view the GT3040R has either too much compressor for the turbine or not enough turbine for the compressor . Big size mismatch between the turbine and compressor diametres . I would not knowingly use a GT3040R on anything , my gut feeling is a GT3071R (the real one has a full sized GT30 turbine and a T3 flanged GT30 turbine housing - CHRA no 700177-5023) should work well on an RB25 with std pistons etc . It is an off the shelf Garrett turbo + housings so getting housings is reasonably easy . Have a look at the ATP Turbo site and the 3071R they offer . I would steer well clear of the "GT3071R WG" or waste gated as it uses the wrong flange (T28) and is a dog anyhow .

Cheers A .