ATP's GT3071R is a great match for the EJ 2.5L engine, especially if you're looking for boost threshold that is close to stock but want enough airflow for 450+ hp. Almost all the boost is available all the time; even at part to medium throttle!. Boost recovery between gearshifts is awesome with full boost ready even before upshift is complete as the STI lurches forward with shear enthusiasm at the onset of each gear. If you have a built 2.0L and are shooting for 450+ hp, this turbo will work, although it will have significant lag. The modern generation of Garrett wheels, coupled with an awesome wheel ratio, allows even the smaller displacement EJ20 engine to provide adequate motivation to get the GT3071R going for a great powerband. The 3071R competition-grade turbo still offers the best response and spooltime out of any unit in this flow range. The GT3071R uses a 60mm 84tim turbine wheel and 71mm 56 trim compressor wheel.
| ATP recommends that you use a bellmouth downpipe with their bolt-on Garret WRX & STi turbos for optimal performance. Stock-type flat plate WRX & STi downpipes (HKS, DC Sports, etc.) and divorced wastegate downpipes (Perrin, Invidia Divorced) do not allow enough clearance for ATP's custom wide-swinging wastegate door. This can result in boost "creep," "spiking," and inaccurate boost control. The Turbo XS & Invidia Bellmouth downpipes would be good choices for use with this turbo. |
| In addition, ATP reccomends a higher flowing 3" turbo inlet, like the Perrin, Agency Power or APS. If you must use a stock-sized inlet, you will need to source a 2.4" to 3" reduction coupler, as the ATP turbos have a 3" inlet.We recommend using a matching-sized 3" inlet for minimal restriction, since GT turbos thrive with minimal inlet obstruction. ATP's tests have shown that these turbos, when used with the stock sized 2.4" inlet, produce significantly less power than when used with the 3" inlet. When coupled with a 3" downpipe, the 3" inlet promotes faster spool, and higher power numbers with less pressure at the manifold. |
