[mangiavelox]

I need an aftermarket manifold in oem position to put on my -5's but I'm not decided wich one to take.

I readed that the tomei have the problem to scratch.

On RHDjapan I see the Flatwell but I don't know the quality and the facility to put it on one piece.

RHDJapan : Flatwell Exhaust Manifold Twin Turbo - RB25DET RB26DETT

There is another on of the brand HPI

http://justjap.com/hpi-stainless-exhaust-manifold-set-nissan-skyline-gtr-hpex-rb26tb42.html

Anybody have some advices ?

 

[Cris]

I need an aftermarket manifold in oem position to put on my -5's but I'm not decided wich one to take.

I readed that the tomei have the problem to scratch.

On RHDjapan I see the Flatwell but I don't know the quality and the facility to put it on one piece.

RHDJapan : Flatwell Exhaust Manifold Twin Turbo - RB25DET RB26DETT

There is another on of the brand HPI

HPI Stainless Exhaust Manifold Set - Nissan Skyline GT-R & Stagea 260RS (RB26DETT)

Anybody have some advices ?

Why do you need new manifolds?

Most consensus is that OEM manifolds can be ported to provide a 'good enough' solution for stock location/type turbos.

 

[GTRgav]

Give the 6boost manifolds a look in. Very heavy wall steam pipe which doesn't suffer the expansion and embrittlement of the Tomei SS manifolds.

 

[Sub Boy]

Pointless unless going single

 

[GTRgav]

Pointless unless going single

They make low mount manifolds also. I have a pair fitted using GTX turbos.

 

[mangiavelox]

Thnak's for the advice. I think that I will port my oem manifold, cheaper and stronger for the oem position

 

[GTRgav]

No problems.

OEM ported manifolds are definately cheaper and support heat shields and water/fuel lines without modifications. Let me now if you want pics of my setup if you change your mind.

 

[Sub Boy]

They make low mount manifolds also. I have a pair fitted using GTX turbos.

Still pointless

 

[GTRgav]

Still pointless

A bit like your post

 

[Jayman]

A pair of ported stock manifolds are by far the best option. Stay away from SS manifold - they do and will crack.

 

[Cris]

They make low mount manifolds also. I have a pair fitted using GTX turbos.

Have you got a build thread somewhere with some pictures by any chance?

 

[meathead]

Standard manifolds

Standard manifolds unported is the best.
Porting just slows down gas velocity and response.
Porting is a surefire way to kill response.

 

[microg]

manifold

spend your money on better dump pipes instead!

 

[mangiavelox]

I just port my oem manifold, my next step is to port my 2530's housing. The dump pipe I have HKS divided.

Sorry but I don't understand why porting the manifold kill response. You have more hair flow for the turbos, normally the go on full boost faster

 

[meathead]

Gas speed/impact on turbine blading is reduced.

I just port my oem manifold, my next step is to port my 2530's housing. The dump pipe I have HKS divided.

Sorry but I don't understand why porting the manifold kill response. You have more hair flow for the turbos, normally the go on full boost faster

 

[mambastu]

If you port match and remove the OEM casting imperfections you'll get an increase in gas speed.

 

[mangiavelox]

There is two different opinions ?.

Porting the manifold and the turbine exhaust housing normally there is more air faster to the turbine wheel. OK that the passage is bigger but inside the turbine housing the passage is tighter

 

[mambastu]

You should be wary of increasing the volume of the pipework pre-turbine wheel too much. It's not particularly undersized in standard form but the head port to manifold face area can do with port matching as can the manifold to turbine housing face. I also wouldn't change the internal shape of the turbine housing either. Its been designed in a certain shape which varies with each model of turbo. On the larger -10s one of the turbine bousing retaining bolts projects in to the inside of the turbine housing so that can be shortened slightly.