yeah i did assume that, i mean why replace stock manifold, its pretty good right? With stock turbo you wont gain much hp anyway, imo

 

I heard you could get small gains (In the realm of 5-10Kw atw) with a properly built manifold over stock.

What I was more interested in though, was getting under-hood temps down by ceramic coating. I thought if I was going to go to the hassle of removing the stock one, I may as well go for the extra 5-10kw, and pay $600US for the manifold.

The flange hasn't changed, so I still need to go for a twin scroll reverse spinning turbo. Not easy... I've been told the HKS 3035S is a straight fit, but I can't see any evidence of that.

 

I seriously doubt it will fit, unfortunately. The four bolt pattern is not symmetric on the EVO turbos, but the HKS stuff up to 3037S at least uses a Garrett T25 flange which is rectangular.
If you need manifolds like that, I sell them. In fact, Al (alfriedesq) had one on his car (ceramic coated) and it made about 9 wheel foot pounds pretty much across the board (particularly from spoolup to 5250) and delayed spool by ~100rpm.

 

Quantum

I've been told I can just get a flange that *will* fit the turbo I choose, saw off the existing flange and alloy weld on the new one. Is this true?

Is it really that simple to make the turbo fit?

 

I have considered something like that myself, but you will need a turbo that will physically fit in the confined space whilst hanging from a manifold that was designed for reverse spin. You see, if you look at your stock turbo setup from the front of the car, the turbo comes off the manifold and curls downward and to the rear (toward the engine). This setup tucks the turbo in nicely without making the exhaust gasses taking a sharp turn downward right after leaving the head. The flange on the manifold is sticking very far forward. If you mount a conventional turbo, when the turbo housing comes off the manifold it will curl down and forward . That will not fit. It will hit the radiator. You can't mount the turbo pointing the other way (a la EVO 1~3) since there is stuff in the way. You could build an adapter that would go from the manifold flange and curl down and in a bit (all the while combining the twin scroll into single) and then allow for a T25 style flange (or T3, etc). Even if you got the turbo to fit by just torching the old flange off, you are going from twin scroll to single with no transition. It will leave a sudden increase in exhaust diameter that will not allow for the best of flow. The outlet of the twin scroll looks like this: 00 and the inlet to a single scroll turbo looks like this: O. The divider in the middle is of consequential size and that would need to be addressed. Or course if you are cutting the flange off, you could do some torching/grinding in there to combine it I suppose.