steven botes

No offence, but ur wrong lol

The turbine (exhaust) housing is marked on the inside - where the flange meets the manifold.

Secondly - an RST turbo is 0.36 as std - cossie T3's are 0.48.

You are correct about the compressor housing - 0.42 A/R - the same on all RS T3's. How ever, the compressor wheel is different - 45 trim on an RST, 55 trim on a 2wd cos, 60 trim on a 4by cos.

BIGEVILRTS

Only way to know is to take it off. Boost at 4k could be a wild or incorrectly timed cam, or a 48 rear housing.