E85 mixed 50/50 with 100% gasoline

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Jun 15, 2003
I think you'd wind up with "E43".

Not a good scene, your block learn/fuel integrator can probably only compensate by 15%... and E43 would have 21% less "zip".

I would keep it below ~15% by volume as purchased at the pump, or even less if the "regular" fuel is 10% ethanol.

Not to mention what could happen to your fuel system parts if they weren't designed for it.
I've been thinking a lot about E85 lately, even though it's not available in my area. What I'm wondering is this:

Let's say I mixed 7 gallons of E85 with 7 gallons of 100% gasoline. If my calculations are correct, this would amount to "E26". (74% gas).

What would such a mixture be likely to do in my '00 VW GTI 1.8T?

What say the BITOGers?
I ran an E50 blend in my '97 Grand Prix, and my Long Term Fuel Trim stayed right around +14.6%. It went like a rocket...considerably more power than straight gas, but MPG was horrible...I only got about 12 MPG on that tank compared to the nearly 30 it would get usually.

I used to run E20 in it all the time with no issues. LTFT was ~+4.5% on E20, and close to 0 on E10. Straight gas put it ~-2.7%

I expirimented with this for a while when they built the first E85 station close to me. They served up 3 different blends...E85, E20, and E10. For a while, they were saying E20 was okay to use in anything, but now there's a sticker on the pump saying it's for FFVs only. The guy I talked to said it's more of an EPA and warranty thing than any problems the cars might have.

I know I didn't have any problems...E20 is 91 octane, and kept any knock down to a bare minimum, along with being 5-7 cents a gallon cheaper than E10.
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