I'm putting an ethanol content analyzer in my car and will likely check the content after almost every fillup.
I've read of guys doing this because the ethanol content varies between stations and deliveries. I haven't kept track of the ethanol content at the local pumps but I try to stick to 1 station that's nearby my house. So far I haven't experienced any oddities related to ethanol content fluctuation.
Quick Fuel makes a $15 e85 measurement tube, I'll probably grab one to satisfy my curiosity.
http://www.quickfueltechnology.com/specialty-parts/echecker---e85-fuel-test-tube.htmlSo you don't worry about being knock limited at all when tuning with E85, eh? Knock and CF's are still good indicators to make sure the tune is safe though, right? (E85 doesn't affect the knock sensors ability to detect actual knock or anything like that, right?) I'm new-ish to MBT tuning as well, but is MBT boost independent then?
I'm still learning but in my limited experience I have not been knock limited with e85. It's very resistent to knock and so knock volts and CFs are misleading.
A lot of people tune timing based on knock and CF, including guys on regular gasoline. This is useful for people who don't have a dyno or some controlled environment to measure performance. My understanding is that the correct way to tune ignition timing is to advance until max torque is achieved or when knock occurs (then back down a little). I've been told "e85 won't knock" and in my experience this has been true.
On gasoline tuning ignition timing based on knock and CFs is fine if you don't have the luxury of a dyno. On e85 you won't get accurate feedback of the car's performance from knock volts.
I've been using the same stretch of road and monitoring my FATS. My timing logs:
So again, my answer is don't advance timing based on knock with e85. Advance until you stop making power.
