Barge
Hard-core CEG'er
A cynical thought for you. Between warranty issues and protecting the Prestige of the Premium SVT power ratings (something like 170Hp SE vs 190Hp SVT-depending on year) - which is more important to Ford?
Obviously, warranty. But I would argue that running richer than 10:1 was absurdly un-necessary.
Finally, from personal experience running calibration on an engine-dyno I can state that even on air-cooled engines (NA) running any richer than 12.2:1 will cause torque to fall off. Running lower than 11.5 will begin quenching combustion and <9.7 rich misfire predominates (excluding cold-start).
Well i'm sure it's a line between warranty and performance but the fact that some amateur can throw a tune onto an SVT and gain 10-15hp means that they didn't try to eek all they could out of it.
I agree that richer than 10:1 is absurd...
I run my WRX at around 11.7:1 - 12:1 with water injection. From the factory it runs in the 9:1 range at high load areas.
Edit: If your engine is knocking there should be an indication that you can log. Either a knock sensor reading or timing correction or just the timing vs. what the timing should be.