We bolted the new Blouch 20G-XT turbocharger to our STI, and rolled it back onto the dyno for some more pulls. The turbo delivered as advertised. Spool was a little slower than the Tomei ARMS turbo we had on the car before, which is understandable given how much larger the turbine outlet is on the 20G-XT. The car made a lot more horsepower at the same boost levels -- 33 more hp and 30 lb-ft of additional torque to the wheels. An added benefit that isn't seen on the dyno graphs is that off-boost throttle response is better -- the more wide-open turbo outlet probably is the reason. The exhaust note is a bit louder now, too!
Most of the time when we put a 20G on a car we've also done a turbo induction hose, TGV deletes, and headers, none of which are on our car. When we do get those mods done, we'll dyno again. I'd expect another 10+ hp at that time.