Drove to 2 different gas stations and tested their E85. This is what I got around me.


RaceTrac (farthest away after me)


BP (closest to me).

BP had a slightly higher ethanol rating which is good because its the closest one to me. Looks like E76 or 77. I think I needed just a tad bit more ethanol from the pump as ypu can see its not quite to the line but still, pretty good considering its early Feb.

 

I did that about month ago too. I had 70% and 75% at two places. I went to a third and it had like 95% or I couldn't see any gas separation. I also couldn't smell any gas in the jug I filled. I'm sure they didn't forget to mix it but still kinda strange.

 

Pretty normal honestly. Most stations are 70-80% Rarely are they more.

 

I got a tip about Speedway E85 from a guy that does a bit of drag racing (most of his cars run E85 full time). He said that Speedway always seems to test very close to E85. I have one that is about 20 minutes from my house so I'll probably go there and test to see what it is coming in at. Not that I'll drive that far to fill up but good to know my options.

 

Yeah but, don't go out of your way for more e85 content, it's irrelevant as hell and with flex fuel it doesn't matter for the tune it will compensate all on it's own.

e70 vs e90 might be worth 1 MAYBE 2 horsepower.

 

Not to steer this off course but I'm making 1000whp and wanted to switch to E85, what would be considered a safe content? If your running say E70, then your fuel system wouldn't have to be that much demanding.

 

From my understanding, most of the knock prevention is provided in as low as E30 range which is why that's such a common blend without taxing the fuel system too much.
E50 is typically the next step up for safety as long as your fuel system can handle it and e70+ is basically considered full E85.
I pretty much never test my E85 anymore (however I always monitor certain pids or datalog) but at the beginning I was and even at 70% I was getting full timing with no knock at 800+hp.

 

Also, it's much easier to size your fuel system to run full E85 then to try to stretch it with a blend.
I blended down to E30 for a while on the stock fuel pump and E50 with a bap but that got old pretty quick.
So much more convenient to just top off E85 and go.

 

like 75% of the benefit of octane is around e30 (when mixed to 30 with 93 octane, not 87)
99% of the benefit of octane: e50
99% of the benefit of combustion cooling: e70

Specifically for engines with direct injection.

For strictly port injected, e70 is what i'd want for 99% of the octane benefit and i'd want e85 for 99% of the benefit of combustion cooling

You can run e70 and make 1000 whp as long as you're not pushing what is providing that boost too hard past efficiency.

 

Good to know. I have about 80 miles to E per the computer so hopefully by this weekend I'll be down to around 30-40 to E and I'll go top it off. I plan on going through that tank, topping off again, then loading my 5Star E85 performance tune.