Im running a garrett t3\t04e 60trim .63 a\r turbine housing which will do about 450 horsepower. On my ka I make power at 3650 with a stock engine + tubular manifold and 3inch down pipe. If you were to bolt my turbo onto an sr20 I would not expect you to see full boost before 4200 rpm. I estimate these numbers with a manual boost controller. If you use an electronic boost controller and properly set the gain it should drop your full boost rpm around 200rpm. (This is a journal bearing turbo, ball bearing turbos will spool a few hundred rpm earlier).
TonyMac, wouldnt a GT3076R be a better match with additional headroom to boot? are 3071r's available non wastegated?
Look around on forums for dyno sheets that list the persons turbo and see what rpm they make power.
Choosing a compressor is a much more critical decision determining how much power a turbocharger is going to make. The turbine housing determines the turbochargers response to the engines exhaust gases. If you are designing a custom turbocharger it is critical to properly match turbine and compressors. In your instance, research to hear what other people have said about their turbine size and engine response, then take those turbine housing specifications and match it to a compressor that will support the power you want to make. Check turbonetics and garrett websites for a chart illustrating different turbocharger horsepower ratings.
