# Hand porting a turbine housing



## v8killer (Oct 19, 2002)

Hey guys,

I have a Garrett T3 4-bolt turbine housing. It does not have the 4 cast bumps in the corners like the older style 5-bolt housing. Does this type of housing still need to be ported? If so, how deep should I go with the porting?

I did notice that the 4-bolt housing has a slightly smaller inlet than the 5-bolt housing. When looking at the turbine inlet, the longer part of the rectangle is 61mm on the 5-bolt housing and only 58mm across on the 4-bolt housing. I was thinking of enlarging the inlet of the 4-bolt housing to match the exact size of the gasket I will be using, which measures 61mm across.

Any thoughts here?


----------



## Altimat (Jul 8, 2002)

I would just port-match both flanges to the gasket and clean the housing up just to smooth the surface and taper it nicely to the flange.


----------



## Boosterwitch (Apr 15, 2002)

I'd suggest getting the turbine housing extrude honed after you port it also. That usually yields about 200-300 RPM earlier spool from the gained flow.


----------

