Although the Tomei ARMS turbocharger on our STI made decent power, and spooled very nicely compared to the stock hair dryer, we just can't leave well enough alone. We asked our friends at Blouch Turbo if they had any suggestions for something with just a little more oomph, and we got a Blouch 20G-XT: A Mitsubishi 20G compressor housing and center section mated to a custom Blouch turbine side that will bolt on to any 2002-07 WRX, and any 2002+ WRX STI. But wait, there's more. The compressor wheel is not cast like traditional wheels. Instead it's CNC milled from a block of billet aluminum. That means it can be made lighter and more efficient than old-school compressor wheels. The upshot is supposed to be more power and better spool. We'll find out next week when we bolt the turbo on and roll the car back on the dyno.
The 20G turbo has always been my "go-to" turbo for 2.5-liter cars. It spools almost like a stock turbo, but has massively more top-end. If you have a 2.0-liter car, the 18G is probably a better choice, as the 20G takes a while to get going with only a 2.0 engine blowing on it. Blouch also has an 18G-XT available. Watch our web site for more details on purchasing these turbos soon.