RB25 -What turbo ? GT3076R or GT3582R.

[BigKriss]

My escapades of late with these two turbos have really tought me something when it comes to these two turbos on the RB25 engine.

Firstly I ran the GT3076R on my car. A.R.63 turbine housing on both of them.

The 3076 started boost at about 3200 rpm with a tire lighting full boost at 3500 rpm. The onset of power is brutal and extreme to put it mildly . Two black tyre marks up the road and quite spectacular but a marked lack of urge from around 6500 rpm.
On the dyno we saw 340 NM at 3800 rpm which makes for an extremely fun car between robots.

I fitted the GT3582R two days ago and what a pleasurable turbo for the RB25 !! Boost starts about 300 rpm later than previous with less torque when it comes on full. The carry though , is spectacular right up to redline which is set at 7100 rpm. Full boost is reached at 3800 rpm which is great.

I was researching the two turbos for hours before deciding on the GT3582R . What is very evident is that the smaller turbine shaft IS a restriction at big boost (1.6bar and up) with the 30 shaft.

Garrett have actually officially brought out the GT3576R for this very same reason.

Most of my runs were at 1.5 bar boost with these two turbos.

The GTX series turbos in the 30 trim only flow 3 to 5 % more than the GT wheel where in the 35 trim turbine they actually get the stated 10-15 % higher airflow.
The reason was the restricted turbine of the 30 turbine.

This I must admit is at boost pressures of 23 psi which I played with-lots of NF !

You guys running the 30l Toyota 2j engines wanting a turbo for drifting ?? (Ernest ?)

GT3582R all the way ..or even that TO4z ! That is going to work like crazy !

[rat]

My gt3071r with a 0.86 exhaust side holds boost all the way to redline (8000rpm). Get 1bar at about 3500-3800rpm

On a stock internal rb25 this works very well. Anything bigger and I think gt35 all the way.

[BigKriss]

Sea level makes a difference though. I drove your car and wished mine was as good as that. Push the boost up and you will find that at about 23 psi the figures are pretty stagnant..The turbine does not flow enough around those levels.

[rat]

most i have run is 1.2 bar, need more nf