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Old 06-27-2012, 07:33 AM   #12
Vlad
Scooby Guru
 
Member#: 46135
Join Date: Oct 2003
Chapter/Region: Tri-State
Location: NY
Vehicle:
19 GLA45 AMG
C63 AMG

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It is because the larger pistons have less knock resistance and other things, that timing is engine-dependent.
The 257 can run less timing, because of this and other things, conversely the 207 can run more timing and should not be judged by 257 standards.

Seeing high timing values in the 207 table only means that this is what Subaru determined for this engine, it should not be read as high or low timing, it's what they think works.
The factory can afford to blow up engines and rebuild them during testing as much as they need. They probably have teams of people that are paid 8 hours a day, to run simulations, dyno time, field conditions, etc.
I'm trying to learn from what the factory is doing, not to dismiss their work.

The A line has the same EJ257 internal dimensions, BTW AVCS is unchanged in table between USDM and JDM, for the 257, at least on the intake side. But I think exhaust too.

It could very well be that an engine has good knock resistance on 93 and bad on 91.
Which does not mean that your research to determine what you should run on 91 fuel, is not important.
I just don't think you can extrapolate back and forth between what an engine does on 91 and what it does on 93.

The feedback at high RPM should be looked up against the MAF maxing out in the high cells.
Once I went to a large MAF I had to change a bunch of things, but I'm running a medium size turbo and other things.
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Last edited by Vlad; 06-27-2012 at 07:45 AM.
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