The AEM intake for the 08+ WRX/STI is about 10% lean, so it is definitely best to tune for it. Intake manufacturers like to build intakes that lean the engine out, because it makes power on the stock overly-rich engine. What tends to happen though is the ECU learns to add fuel and the gains from that are gone after some driving/learning time.
The stock intake for the 08-13 WRX/STI and the 05-09 LGT is not as well designed as the one from the 02-07 WRX/STI from a power and tuning standpoint. The air has to make a sharp bend going into the intake tract before the MAF sensor. This is why Subaru put air straightener fins in there I believe.
The StockMAF KSTech intake for the 08+ WRX/STI took 4 prototypes to get it right. It follows the stock MAF calibration pretty well, and does not *require* a tune on a stock or stage 2 car, and it does not try to make power by leaning things out. But it does probably make power by reducing restriction
A KSTech dealer, EFI Logics in CT did a comparison on a 2012 STI stage-2 car, with and without the KSTech intake. They have installed and tuned maybe 100 these type intakes - more than any other shop I know of. The car went from 266whp with the stock intake to 285whp with no other mods. Now, I would not try to claim the full 19whp gain from the intake, but I think that 10+whp from a good intake is a reasonable assumption.
|