There's a gas station around these parts called "Jumpstart" that does an exceptionally poor job of labelling their fuel properly. They have 93 octane (which isn't common in the Midwest) and as far as I can tell it says nowhere on the pump that it's E30 (it is) - simply that it has "Kansas ethanol".
Lucky for me there's a Casey's about the same distance in another direction that has real 93oct with 10% ethanol - for a substantially higher price.
I've done some Internet Sleuthing and earned my Internet PhD (worth the paper it isn't printed on) but I wanted to bounce the topic off folks here.
My truck is FlexFuel so it'll run on damn near anything flammable and I've ordered an ethanol test cylinder so I can check to verify that they're selling unmarked E30 at their pumps.
From what I've read the primary concerns for running E30 in a car rated for only E10 or E15 are:
- Reduced Fuel Economy
- Potential HPFP clogging
- Hotter Engine Temps
The first and last are less of a concern for daily driving, and the middle one seems connected mostly to cars that are infrequently driven.
I saw one dyno graph that showed E30 on a stock 91 octane ECU tune (different vehicle) had some modest hp/torque gains, and then tuning for E30 gave even higher gains.
So I'm wondering exactly what harm running E30 in the GR86 could cause, since I'm now considering the possibility of getting an E30 tune in the future. It'd be nice to be able to do some side-by-side testing on MPG between standard 93 octane and E30 octane - both on a proper ECU tune - to see if there's actual money to be saved. (E30 is a lot cheaper at Jumpstart, but if you use enough more per mile it isn't actually a bargain.)
Obviously if it's going to clog stuff up or otherwise risk the warranty, that changes the math considerably.