Porting Exhaust Manifolds & Turbo Inlets?

[Micko]

Hi people, I am in need of some advice & hope somebody can help me make the right decision...

I am waiting on a set of HKS2530's to come in from Japan. I have been waiting a while so I been doing a few basic things in order to get the most efficiency & performance out of my setup.

Upon the advice of a local tuning shop, I had the manifolds match-ported to the head & had the outlets ported out to be the full size of the gasket that goes between the turbo & the manifold. Since then the manifolds have been ceramic coated.

The issue is that I was looking at some pics of the turbos in a magazine & it appears that the exhaust inlet on the turbos is the same size as the factory ones (not larger as I was told, but I will have to confirm this once the turbos arrive), meaning that I should have left this side of the manifold alone...

I need some advice on what to do from here. The way I see it my options would be:

1. To port out the inlet on the turbo to match.

2. To use another set of manifolds.

3. Just bolt it all up & don't worry about it

Any advice appreciated.

*Note to self - be patient & check things before you modify them!*

Regards,

Mike.

[KamikazeR33]

if i was u i would port it, no point having more zaust air being drawn up and cant be pushed out as its released, imho this would create lag and back pressure

[Steve]

This is something that I was looking at a while back.

I came to the conclusion that it probably isnt really all that necessary, as turbine housing itself is alot more restrictive than the manifold.

As long as there are no rough edges anywhere, and every joint meets seemlessly (ie manifold to turbine matched) that is about all you can do without increasing the AR ratio - which will of course effect where in the rev range the turbos operate at peak efficiency.

It may be possible to extrusion hone the turbine housing, with out effecting the AR ratio overly, but the size of the inlet to the turbine housing itself, if its larger than the path the gasses has to follow as they travel through the turbine, should be fine.

Does that make sense?

Just to qualify, this is all I have found from research, so its possible that like so many other things, paper and the real world differ:D

[Micko]

Thanks for the suggestions - spoke to someone today & he said to port out the exhaust port on the turbo to match - at the end of the day the hole is still the same size at the bottom, so it shouldn't make any difference.