Thread: Turbos.

I am currently researching turbos for a bolt up.

The most consistent recommendation from turbo dealers seems to be for a Garrett gt28 with .48 a/r exhaust and .60 a/r compressor - for quick spool with out running out of puff at high revs.

I think Justin uses a high flow t25 with .48 a/r exhaust and is very happy.

A couple of others have used/recommended t25s from nissan rb20 that from memory have a/r of .64 exhaust .60 a/r compressor.

I have also been recommended a mitsubishi TD05 - 16G (used on the Evolution) which sounds like about the same size as t28 or t3 garrett.

I have been told the later NPRs with the 4BD1T were fitted with a t25 with exhaust a/r .67 and compressor a/r .48.

I also had a look at a new chinese 4bd1t at Brisbane, was fitted with a tiny Garrett turbo - i'm guessing it was a t20. These were top mounted but the turbo flange was raised so the outlet fed straight accross the top of the motor.

I think I will either go with a new GT28R or 2nd hand high flow T25 if I can find one.

Originally Posted by rar110

I am currently researching turbos for a bolt up.

The most consistent recommendation from turbo dealers seems to be for a Garrett gt28 with .48 a/r exhaust and .60 a/r compressor - for quick spool with out running out of puff at high revs.

I think Justin uses a high flow t25 with .48 a/r exhaust and is very happy.

A couple of others have used/recommended t25s from nissan rb20 that from memory have a/r of .64 exhaust .60 a/r compressor.

I have also been recommended a mitsubishi TD05 - 16G (used on the Evolution) which sounds like about the same size as t28 or t3 garrett.

I have been told the later NPRs with the 4BD1T were fitted with a t25 with exhaust a/r .67 and compressor a/r .48.

I also had a look at a new chinese 4bd1t at Brisbane, was fitted with a tiny Garrett turbo - i'm guessing it was a t20. These were top mounted but the turbo flange was raised so the outlet fed straight accross the top of the motor.

I think I will either go with a new GT28R or 2nd hand high flow T25 if I can find one.

IMO T28's are too big.

I have run a T25 from a Nissan CA18DET and will again shortly (I lost an oil line and blew it up). It has a 0.48 A/R turbine housing and starts to spool approx 1400rpm, max boost arrived a little over 2000rpm (last time I had it running, the engine was quite sick, hopefully can update that soon).
A T25 with slotted holes will bolt to the IHI manifold.
I ran it with both boost and backpressure gauges. As a single turbo replacement for the IHI it's your best bet.

A T3 will bolt straight up to the 4BD2 style manifold, they are available in a range of suitable sizes from tiny to too big.
RB20 turbo is a T3 and probably your best match in that series.

The later 4BD1 and 4BD2 turbos are T25 non wastegated with a T3 inlet flange. Compressor is identical internally to the CA18DET T25 that I have.