Quote:
Originally Posted by D_Thissen
@ Gforce The FA20 in our cars and the FA20DIT that's in the new WRX are different motors. The DIT has a ~10.5:1 CR vs our ~13:1, different fuel systems (DI vs DI/PI) and I believe different rods.
"My tuner verified for themselves that Shell 91 gives the best engine performance in my area. The 92 and 94 offered by others has too much ethanol in it and does not give better real world performance than ethanol free Shell 91. My seat of the pants dyno confirms that with my other three cars, two of which are also boosted."
The butt dyno is irrelevant source of measurement. |
The FA20 is built in two versions: turbo and non turbo. Which is what I wrote. I don't think we know for sure what Subaru may have changed when upgrading the engine for forced induction. The crank is an unlikely candidate for change given that it is the single most expensive engine part. We know the pistons are different, and I mentioned that reducing the compression ratio would form part of any built engine for more boost. It is doubtful the rods are different for the wrx version but the STI version would need stronger rods.
As for the relevance of the butt dyno well that's the only one that counts for a daily driver. Also, accuracy of butt dynos may vary. I have an excellent one, according to my wife the only judge of same I pay any attention to.