E15 gasoline

[Lineman]

I blend E85 w/87 octane so that I blend out to ~95 octane. My SUV is tuned to run that and the duty cycle on injectors can handle the load at WOT.

Simple ECU + TCU tune on a stock SUV with gas blend makes almost 700hp and lets my 3 row family truckster run high 11 sec...

I swapped my old Nova over to ethanol/gas about 10yrs ago. I found that RS Fuels off Memorial sold E100, not sure what octane it equals to but I did not have any issues with detonation with a 14.0-1 alum headed “396” nitrous engine.
My fancy test tube showed 90% and I used 91 to mix. All I know is my fuel cost was cut in half, rarely run both fans and you could keep a beverage ice cold on the intake… 4.10s, 28” tire and PG right at 3200 = around 4.5mpg.

 

[OKCShooter]

I swapped my old Nova over to ethanol/gas about 10yrs ago. I found that RS Fuels off Memorial sold E100, not sure what octane it equals to but I did not have any issues with detonation with a 14.0-1 alum headed “396” nitrous engine.
My fancy test tube showed 90% and I used 91 to mix. All I know is my fuel cost was cut in half, rarely run both fans and you could keep a beverage ice cold on the intake… 4.10s, 28” tire and PG right at 3200 = around 4.5mpg.

Cheaper fuel for sure...My tune is for 93 so I blend to 95ish to be safe (Twin turbo V8)

I blend fuel for my Wife's SUV and My Son's as well - no tune but blended is cheaper than 91 by $25/tank and it runs very well (both have turbo engine as well)

I am surprised most people don't blend E85 in to 87 for the cost savings. Pretty much any vehicle can run on 15% ethanol and most well higher. My tune is considered an E48 tune.

 

[TulsaMike]

I swapped my old Nova over to ethanol/gas about 10yrs ago. I found that RS Fuels off Memorial sold E100, not sure what octane it equals to but I did not have any issues with detonation with a 14.0-1 alum headed “396” nitrous engine.
My fancy test tube showed 90% and I used 91 to mix. All I know is my fuel cost was cut in half, rarely run both fans and you could keep a beverage ice cold on the intake… 4.10s, 28” tire and PG right at 3200 = around 4.5mpg.

The only issues with e100 are extreme cold starts or hot weather restarts. The 15% gasoline is solely mixed for ease of starting so the fuel doesn’t gel as badly, but if it’s not an outdoor car or daily driver, that really isn’t a problem, and even if it is, the car usually behaves normal once it’s warm. Some cars if not tuned properly can be tough in really hot climates and will have symptoms of vapor lock.

 

[TulsaMike]

Cheaper fuel for sure...My tune is for 93 so I blend to 95ish to be safe (Twin turbo V8)

I blend fuel for my Wife's SUV and My Son's as well - no tune but blended is cheaper than 91 by $25/tank and it runs very well (both have turbo engine as well)

I am surprised most people don't blend E85 in to 87 for the cost savings. Pretty much any vehicle can run on 15% ethanol and most well higher. My tune is considered an E48 tune.

Most pump fuels are already 10-15% ethanol, but the issue with blending if you don’t have an alcohol gauge is what the actual content is. Most ethanol is minimum E50, but it can be up to E85, and as some have stated, if it sits in a underground tank for a while, you never know what you’re going to get. My Audi wasn’t flex fuel so I ended up buying a flex sensor and gauge, and monitoring the alcohol content because my tune was designed for E70 and 36 lbs of boost, so much under e60 would be a rough day if I didn’t swap tunes. My truck now is flex fuel, but it’s blown so I have to leave it at a 91 friendly boost level, or make sure I always run ethanol, or a can or two of torco if I run higher boost.

 

[Lineman]

Cheaper fuel for sure...My tune is for 93 so I blend to 95ish to be safe (Twin turbo V8)

I blend fuel for my Wife's SUV and My Son's as well - no tune but blended is cheaper than 91 by $25/tank and it runs very well (both have turbo engine as well)

I am surprised most people don't blend E85 in to 87 for the cost savings. Pretty much any vehicle can run on 15% ethanol and most well higher. My tune is considered an E48 tune.

I ran a 88 Thunderbird TurboCoupe at 25% on the stock ECU. Ran good but anymore the ECU just didn’t seem to like it but it would still run just couldn’t correct the AFR above that I guess.
I think I read somewhere that OEs had started in the 80s for vehicles to run at least 10% ethanol even with a carb…
I remember a thing before E85 called Gasohol, have not researched anything on that “old” stuff though lol

 

[OKCShooter]

Most pump fuels are already 10-15% ethanol, but the issue with blending if you don’t have an alcohol gauge is what the actual content is. Most ethanol is minimum E50, but it can be up to E85, and as some have stated, if it sits in a underground tank for a while, you never know what you’re going to get. My Audi wasn’t flex fuel so I ended up buying a flex sensor and gauge, and monitoring the alcohol content because my tune was designed for E70 and 36 lbs of boost, so much under e60 would be a rough day if I didn’t swap tunes. My truck now is flex fuel, but it’s blown so I have to leave it at a 91 friendly boost level, or make sure I always run ethanol, or a can or two of torco if I run higher boost.

Plenty of 100% ethanol free pumps so "most pump fuels are already 10-15%" isn't true. Some are and they are clearly labeled.

I use OnCue almost exclusively. Very simple to run 105 octane (E85) along with pure 87 octane. Only "hassle" is doing the 2 transactions. My engine is tuned for an E48 blend at 93 octane. I blend to get no less than 95 Octane. If for some reason the octane is off I am well within safe limits and my computer can retard timing if needed.

I have done this on last two tuned daily SUVs (Both AMG Twin Turbo V8) with zero issues for years and can run high 11's on an otherwise stock vehicle. Zero issue with blending, lol

 

[1911Sooner]

So this got me thinking. I have a Mustang GT and it has a high compression. The manual says 87 is fine to run but recommends 93 octane. Around here I have 87, 89, and 91 octane. I can get 87 octane pure gas no ethanol. But the 89 and 91 octanes both have ethonaol. So my question is am I better off using 87 pure gas vs 91 with ethanol?

 

[TulsaMike]

So this got me thinking. I have a Mustang GT and it has a high compression. The manual says 87 is fine to run but recommends 93 octane. Around here I have 87, 89, and 91 octane. I can get 87 octane pure gas no ethanol. But the 89 and 91 octanes both have ethonaol. So my question is am I better off using 87 pure gas vs 91 with ethanol?

Fuel trims can compensate plus or minus 25%, so the 10% ethanol really doesn’t cause any harm other than slightly reduced mileage (very slightly). If your car is setup for 91, it will run better, but often if it “can” run on 87, the timing isn’t super aggressive so there may be minimal gains unless it’s a newer mustang that has the better knock sensors and can actually add timing for octane.