Physical Size Of Exhaust Housing On Rb20 And 25 Turbos.

[Rolls]

Is the rear housing on rb20 and rb25 housings the same size, I realise the wheel and the area is larger on the 25 unit but is the outside the same?

Reason I'm asking is once bored out if there would be much difference in overall size.

[hypergear]

R33 = .58 turbin / .60 comp

[discopotato03]

No actually , the RB25's Hitachi turbo has a slightly larger passage in its turbine housing or at the least the ones I've measured have .

The actual area radius ratio numbers are irrelevant because its not like you can alter them . You have a choice of small , a little larger , and large sizes - RB20/RB25/VG30 .

All of the above mentioned turbos appear to have the same sized ceramic turbine .

A .