Does anyone have info on the maximum power that can be achieved using the stock GenII exhaust manifold with some good port matching? I need to use this for competition regulation purposes so not interested in arguments about the merits of aftermarket manifolds for example.

The most i have personally done with one, was on a car with toten's old long motor and a stock manifolds (intake and exhaust) with a manifold/gat adapter and a precision turbo.

We got to about 285rwkw before we got to a point we had concerns with backpressure.

My old sw20 was just under 320KW at the wheels on a stock gen2 ex manifold (not ported or anything)

Turbo was a gt35r with an adapter to the stock mani.

Inlet manifold was changed to a large RMR unit though.

Thanks fellas. I do know Jason's GenII in Hobart makes around 300wkw on stock manifold with GT3071 so it sounds like this can be improved on going by Nick's results a few years back.
 
Do you know if there were any flow improvements with the GenIII stock exhaust manifold? Edit: ignore this I read the GenIII manifold cant be bolted to GenII head.

I think the stock ex mani is the way to go personally unless you're shooting for 350-400KW+
 
They hardly ever crack or warp, are free (assuming you already have one), are compact and can easily/cheaply be replaced if required.
 
If I had my previous car these days with E85 available I would continue to run the stock ex mani and prob be up around 400KW mark (30+psi GT35R)
 
Definitely more power would be realised using a nice hand made equal length manifold etc. But that means $$$, likely cracking at some point and extra heat in the engine bay to manage.
 
Those are my thoughts anyway.

Thats the way Im thinking. I may have the manifold ported and gasket matched for better flow.

stuka, what turbo where you thinking of running?
 
I personally have been interested in the mamba gt3071 that is a bolt on http://shop.mambatek.com/product.sc?productId=597
I haven't found any decent reviews for this turbo yet, I'm thinking I might need to be the guinea pig.
 

zvargulis
stuka, what turbo where you thinking of running?
 
I personally have been interested in the mamba gt3071 that is a bolt on http://shop.mambatek.com/product.sc?productId=597
I haven't found any decent reviews for this turbo yet, I'm thinking I might need to be the guinea pig.
 

Another option would be sending your existing turbo to this guy, I have heard good things about his work and have been talking with him about sending my existing turbo to him to be upgraded.
 
http://www.munroracingturbochargers.com.au/index.html
 

zvargulis you need to be wary of these turbos due to boost creep, the wastegate can need a lot of work.
 
Nik_Lee I have been speaking to munro as well, his claims are tempting. So have you heard good things about his work from a good source?

What are his claims? The ideal turbo for me is a gtx3071 or even gtx3076, I know there are compromises taken stuffing that CHRA into a CT20b but for the sake of just a bolt on, I am happy to compromise a little.
 
stuka have you heard anything bad about the mamba turbos? its really hard to find any reviews.