Rb25det Or Rb20det Ex Housing On My R34gtt Turbo

[Birth]

Hi,

I have an R32GTS4 with an RB20DET. I have bought an R34 GTT turbo which I hope to install shortly. The turbo I have bought has the larger OP6 exhaust housing. I understand from many other threads that using the smaller exhaust housing from an R33GST25T on my R34GTT turbo will be less laggy.

My logic / thinking is - if an R33GST25T exhaust housing is smaller than an R34GTT exhaust housing which means less lag, would an R32GTST exhaust housing which is even smaller (that the R33GTS25T) be even less laggier?

If so, would using the RB20DET ex housing mean any / much less power?

Any help / advice would be ver much appreciated.

Thanks,

Ben.

[stolen_s15]

If you are worried about lag then save up for an RB25 engine swap, the RB20 has quite a reputation as being somewhat laggy.

What you are saying is correct, the smaller the exhaust housing (generally) the better the response, but at the cost of top end power.

In any event, none of the turbos you suggest will be very laggy, and I would suggest using the OP6. The rb20 turbo will limit you to about 170ish rwkw, the RB25 to 190ish and the OP6 to about 200. All on about 13psi, so pick the power you want and go for it.

Just be prepared to get teh power bug and want to upgrade again.

Good luck.

[bubba]

I had a s1 R33 turbo on my RB20 and it made 183rwkw @ 12psi and was making full boost by about 3500rpm. Same turbo on my RB30 makes full boost by about 2200rpm and makes the same power at the same boost but about 1500rpm sooner.