Hks Twin Turbo kit Prototype.

Originally Posted by in.the.dark

Just checked and the GT-RS by HKS is actually bigger than the GT28RS by Garret that I thought this was. The Garret would be a better match. HKS doesn't use Garret turbos, the naming convention is similar, hence the confusion everyone has.

You want something that is in it's efficient range around about a 1.4-1.6 pressure ratio as it sweeps up to enough CFM to support about 300 horsepower (about 33 lb/min of airflow). That would get you to the mid 400s at the wheels with the best street manners on each bank of three cylinders. The GT-RS supports about 400hp (400ps actually). That's about a 33% increase in capability that isn't utilized and only serves to create lag where a smaller turbo may server better in its place.

I understand that there is more at play and that the theoretical is when these turbos are pumping as much air as possible, etc etc. All of these turbos are more efficient at higher boost levels anyhow, but some are a better match for a stock VQ37 than others.

Here's some statistics on these turbos:

HKS GT-RS
========
400 PS Output
COMPRESSOR:
-Wheel- 52 Trim - 51.2 Inducer / 71.1 Major
-Housing- 60 Inlet / 50 Outlet - 0.60 A/R
TURBINE:
-Wheel- 76 Trim - 53.8 Major / 47.0 Exducer
-Housing- GT25 inlet / Internal GT25 outlet; 0.64 A/R

A close Garrett would be the GT2871R.

I went to the Garrett site, since they have compressor maps and HKS doesn't Any way, they have tons of information on these turbos if you are really interested. I could go through these, but I'm really tired.

TurboByGarrett.com - Turbochargers