View Single Post
911TT33 911TT33 is offline
Registered
 
Join Date: Mar 2011
Posts: 598
Quote:
Originally Posted by TurboKraft View Post
This GT30R question comes up frequently.

Simply put, the turbine wheel is too small for a 3.3L engine, and a little big for most built up air-cooled 911 twin turbos. It is a good turbo for 3.0L Turbos, though.

If your power goals are very modest, and you have stock cams -- great. Your engine probably doesn't flow much anyway and you won't find the turbine side restrictive in the camshafts' limited rpm band.

If you have the usual 930 upgrades -- headers, muffler, intercooler, boost, cams -- then the turbine is a limiter. Ex: a 3.6 Turbo with EFI that should have done an easy 520whp on pump gas at 1bar was limited to 480hp, and had much less midrange torque, thanks to the existing GT30-based turbo the client didn't want to change.

Backpressure.
It is your enemy.
Thanks for tuning in, Chris. I tried to PM you privately on this exact topic but your inbox was full

Just out of curiosity, what would spool faster and feel more responsive on a 3.3L/3.4L EFI EVO CAM'd motor:

- A single GTX3076R / GT35R @ 0.82A/R vs
- A pair of twin GT28RS turbo's @ 0.63 A/R ?
Old 06-01-2012, 08:07 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)