Originally Posted by dfv2
Benz, there's quite a difference in torque between 6 degrees at X load vs 10 degrees at x load especially in the upper rpm's.
On ACN swill, you may very well be missing out on 20 whp at 6000 rpm. In my observations the stock DME is designed to ride the knock sensor/correction system and generally take advantage of whatever octane is available. On good 93 octane I still pull timing across cylinders on Stg0.
What I should do is run my tank down to vapor, fill with 1.5 gallons crap 91 from a mom/pop and do a few pulls. Then add 1 gallon of e85 and do a few pulls. I'd compare the logs and the resulting csv dyno's. At least it would help us understand the influence of cleaning up timing on the stock rom with e85.
I live in California so yes I have the unfortunate pleasure of dealing with this type of gas (wohoo). Ive been filling up with 4 gal of 100 oct near me lately, but in california its $8.49/gal.
so being able to compensate with E85 and not needing a tune helps a great deal. And yes there is a very noticeable difference when i supplement with 100 octane. Car runs much smoother and jumps a little quicker.