Advanced 7cm Hsng. porting

[Mirageman]

I have a 4g63 Mirage that is modded to about 315 WHP using a small 16G. I have 2 fully ported T. housings for this 16G and wondered if anyone has ever lathed off metal in the turbine wheel hole to give the same affect as clipping the wheel. Since I have a shop lathe this would be far cheaper than clipping the wheel and the cartridge rebuild needed when taking the shaft out to be clipped. I should be able to accomplish the same affect with this extra housing. I have already had the housings in a lathe to taper the hole at an angle coming away from the wheel to match the O2 gasket. I am trying to see how far I can go with a 16G.
Any thoughts on this?

 

[dsm1kenobe]

Let me understand this correctly...So you want to bypass the TW entirely? This seems to me like a pre-turbine exhaust leak i.e., your engine will have to work harder to spool the turbo than if you didn't have the leak. I doubt it'll work.

You'd want to reduce back pressure through the TW and not wastegate gases around it.

 

[Mirageman]

I think when someone clips a turbine wheel they remove some metal at, 5 to 15 degrees, off the smaller diameter of the T wheel. This is the part that you see when you look in the housing at the T wheel. I believe that a clipped wheel will have more clearance between the wheel fins and the hole where the exh. comes out letting some exhaust escape around the wheel instead of between the fins. Normally there is very little clearance in there. You have to be looking at the T housing with O2 housing off to understand this visually.
What I propose to do is remove some metal from the housing hole instead of the fins, creating the same affect - some exhaust bypassing the smallest dia. of the wheel fins.

 

[RipperXX]

Personaly I think it will work, I dont think it will work as well, but should work.

And if you already have a extra houseing I say go for it.


*Edit* let me say that deferently, I think it will hurt your spool up more however should have the same desired top end effect.