Spying: Subaru WRX

I like it! But those EJ20 / EJ25 engine needs some serious updating though. For one, DI is a must in this day and age. Secondly, the exhaust routing for turbocharger is about the worst I have seen... the piping is long and contorted between the exhaust ports and the rear mounted turbo... that silly cat converter ahead of the turbine really hurts efficiency... and, the entire exhaust ensemble and heat shielding under the engine removes one of the prime advantages of the boxer -- that the center of gravity of the engine can be very close to the ground.

This is one engine where they can really use a reverse flow design where the turbo is above and between the cylinder banks. The manifold should be cast as a single unit as the turbine housing. The compressed charge can then exit the FRONT of the engine and loop down to the bottom where the intake manifold(s) is either through an air-to-water or air-to-air heat exchanger.

Given that the boxer is confined to big bores and short strokes by the need to be narrow enough to fit between the front wheel wheels, instead of trying to run generous boosts, they should play to the advantageous of that configuration -- push up compression, reduce boost and make use of the high revving character of an over square engine. With compression at about 10.8:1 and boosts at a very modest 11.8 psi, you end up with about 220 lb-ft @ 3600~7600 rpm and 318 bhp @ 7600 rpm. An EJ style short stroke boxer has no problems revving to 8000 rpm. This will be the most "un-turbo" like turbocharged engine. The power delivery is very much like a high revving 3.0 liter class engine like the BMW S54 (E46 M3). Fast revving, extremely low lag, great economy at cruise (due to high compression). In fact, it'll be a perfect engine to be shared with an uprated FT86.