Hks Cast Iron Low Mount Turbo Manifolds, Biggest Turbo Fitment?

[Chris Wilson]

What's the biggest turbo anyone has successfully fitted to an HKS cast iron remote wastegate, low mount manifold please? Clearance for large compressor housings looks very tight... Car is R33 GTR Thanks.

[discopotato03]

Chris I believe the one HKS used with that manifold was a TA45S which I'm pretty sure used a .72AR comp cover . The modern equivalent would be a GT40 or GT4088R with .72AR cover .

I would not like to guess if a GT42/42R would fit in the available space , the comp covers on HKS's T51R are enormous so hard to imagine it going in but not sure .

Cheers A .

[carl h]

the gt30r i have on my rb20 using the hks cast manifold comes VERY close to the engine mount and xmember.

cheers.

[Sydneykid]

T66 fits, no problems, for 625 bhp.

cheers

Edited May 3, 2006 by Sydneykid

[Chris Wilson]

  Sydneykid said:

T66 fits, no problems, for 625 bhp.

cheers

Is this on the RB26 GTR engine and manifold in an R33 GTR chassis? I have new cast iron RB26 HKS manifold and wastegate, and an RB25 one as well. I put the RB25 one on the RB25 engine in my R33 GTS-t chassis and it looked as if only a tiny compressor housing would clear. maybe the subtle differences in the RB26 HKS manifold allows a bigger housing? Have you actually fitted this combo yourself? Thanks, I need to be SURE a given turbo will fit before buying one, of course Am i likely to find anything to give an efficient 680 / 700 on this RB26 manifold, feeding an engine with Tomei 280 degree cams, ported head with stock valve sizes, stock RB26 plenum arrangement, all steel internals, 8.5 CR, on an M800 ECU?

When you say T66 is this a Greddy turbo?

Thanks, as i say, I need to be 100% on this! I also need to be able to return wastegate exhaust into the main downpipe because of track day noise issues. That looks relatively trivial I think.

Thanks for the replies, anyone else running this manifold??

[BHDave]

There is a significant difference in the rb20/25 manifold compared to the rb26 manifold (other than the stud pattern).

The most obvious is that the 26 manifold looks to be a lot more compact (obviously to clear the TA45 vs the T04e that the other rb's got). I had a look at the 2 side by side when i was picking mine up.

I'm running a T300s (with a .7 cover) on a low mount rb25 manifold and it took a bit of work to make it fit in my r32 but i got the bastard in there with a little cursing and a lot of bashing. Not that that helps you

[ECR033]

I also have a HKS cast low mount manifold on my RB25 (I know this doesn't help you, but thought I'd just post for general info) running a externally gated GT3040R (.7 cover).

The turbo wouldn't fit with the standard engine mount in place, so we replaced the standard item with a new noluthane Z32 mount and the turbo fitted in nice and snug.

[Chris Wilson]

  ECR033 said:

I also have a HKS cast low mount manifold on my RB25 (I know this doesn't help you, but thought I'd just post for general info) running a externally gated GT3040R (.7 cover).

The turbo wouldn't fit with the standard engine mount in place, so we replaced the standard item with a new noluthane Z32 mount and the turbo fitted in nice and snug.

What bodyshell is this in please? Did you have to alter the shell at all? I suspect the clue is in your ECR033 name, but not sure... Cheers, and thanks, I have an RB25 engine in the R33 GTS-t car at the moment, on an Apexi top moount cast iron manifold with RX-6 turbo and external gate. I am having issues with the wastegate pipe to cast manifold interface blowing gaskets, the manifold is thin at this point, the flange is only 2 bolted, and under circuit use at 1.4 bar boost it is sagging and even stainless multi shim gaskets are blowing out. I have made a stepped adaptor to try and cure this, but if that fails then I think I'll have to put my new HKS cast iron RB25 manifold on with a different turbo. It means all new piping of course, which is a PITA. I am making different fixes for the Apexi one on a regular basis though, which is a shame as it has good runner design and the RX-6 spools really well.

Great info guys, here in the UK the cast manifolds are virtually unknown and sneered at, people seem to ptefer welding up cracked tubular ones on a weekly basis

As an aside I believe the "Horsepower in a Box" mild steel steam pipe tubular manifolds are well respected in Oz? Is that right?

Thanks again.

[Chris Wilson]

Yet another qustion, sorry

On the HKS cast iron RB25 manifold what wastegate did it use, did it mount directly on the manifold, or on a riser adaptor, and are they still available? If it uses a riser adaptor can anyone post a few detailed (big) pics to me at chris@chriswilson.tv please? Many thanks.

[BHDave]

the 20/25 manifold uses an off the shelf 38mm hks wastegate which bolts directly to the manifold.

They are still readily available.

[StockyMcStock]

sounds like you need to make yourself a new manifold, too many problems i can see. pick your turbo to the exact specs you want, then go ahead and make a manifold to suit it. you can place the thing yourself then. even if you just tack it all together and get a pro to weld the seams, you'll get out of it for less than $500 AUD pretty easily. i would back my homemade low-mount tubular manifold against one of the trust cast manifolds any day of the week.

[Sydneykid]

  Chris Wilson said:

Is this on the RB26 GTR engine and manifold in an R33 GTR chassis? I

Innovative Turbos T66, titanium compressor, dual ceramic ball bearing core, water cooled.

RB26 in R32GTR, which is what that cast manifold was designed for.

All of the R33GTR HKS manifolds I have seen are not cast.

cheers

[Chris Wilson]

  Sydneykid said:

Innovative Turbos T66, titanium compressor, dual ceramic ball bearing core, water cooled.

RB26 in R32GTR, which is what that cast manifold was designed for.

All of the R33GTR HKS manifolds I have seen are not cast.

cheers

Do you know / think this combo will clear the chassis in an R33 GTS-t, cos that's what I aim to fit it in. i went to great pains to find a CAST manifold as all the tubular ones we see in the Uk crack. maybe not too bad for road usage, but with the thermal stresses of long periods of WOT on track, they ALL seem to crack. Thanks for your patience with this

[Full-Race Geoff]

  Chris Wilson said:

i went to great pains to find a CAST manifold as all the tubular ones we see in the Uk crack. maybe not too bad for road usage, but with the thermal stresses of long periods of WOT on track, they ALL seem to crack.

A properly designed and manufactured thick wall stainless steel manifold will have huge power gains over a traditional cast log manifold and there is no reason why it should crack. We have seen gains of ~60-80 whp

just by reducing the backpressure in the exh manifold.

[maximajim]

  Full-Race Geoff said:

A properly designed and manufactured thick wall stainless steel manifold will have huge power gains over a traditional cast log manifold and there is no reason why it should crack. We have seen gains of ~60-80 whp

just by reducing the backpressure in the exh manifold.

Any pics of your AWD s14?