[spangenb]

Ok so I just noticed today that a few gas stations here in Erie, PA, are selling "ethanol free 91 octane premium". Didn't check yet what the price differential is compared to the other grades. What's the benefit for the FiST if any? Octane rating is octane rating right? So this ethanol free 91 octane premium wouldn't be as good for high boost as 10% ethanol 93 octane? I am betting a car that likes 91 would see an mpg increase over 10% ethanol 91. Inquiring minds want to know

 

[spangenb]

Wow unless there is some major benefit it's not worth this ...

 

[WScottCross]

It may have some benefit for older cars, but our cars can be tuned for E30 or higher, so with the added cost, probably not worth it.

 

[Karl Kutchi]

mileage will be better after ecu relearn, but maybe not better enough to justify the $0.30 /gallon difference

edit: power may be better/worse as ethanol boosts octane and the ecu may/may not advance timing

 

[totusPorcus]

there are two reasons to run that gas
1. you put it in your lawn mower, weed wacker, leef blower, chain saw (many of these motors fuel systems are not made to accept ethanol and it screw them up)
2. you are a member of the ethanol hate society (and there are many). if you hang around many car forums, sooner or later you will run into the folks who think ethanol free gas is the holly grail and hate the ethanol fuel industry as much as some folks hate al quaida). many of these folks will tell you that ethanol will screw up your car. and it will if was made before 1952....

aside from all of that, you can get slightly better mileage from non ethanol fuel but there is no way i'd take an octane drop to do that.

 

[Methane Herder]

It's what you run in a Triumph motorcycle with a nylon tank (unless you enjoy buying a new tank every 3 or 4 years).
MH

 

[razorlab]

As an FYI, just adding E30 to my FiST, it was advancing ignition timing 6-8* over 91 octane. Pretty big torque difference. About 25ft/lb before any tuning.

 

[BRGT350]

When I was at LSPR last fall with the Fiesta ST and my friend had his Focus ST, we both used ethanol free 91 octane. Both cars were getting really good mileage on the fuel. It was shocking the difference! I had a picture of the Distance To Empty reading well into the upper 400 mile range. I wish I still had the picture on my phone so I could be accurate with the distance. I wish I could find ethanol free fuel to use in my Mustang since it is carburated and not designed for any fuel containing ethanol.

 

[hollywood]

I'd get that ethanol free for my lawn mower or my Jeep Comanche, but that's about it.

 

[Cligedy]

There is a station near my house with ethanol free 93 octane. I do my best to stop in and gas up there before autocrosses. It may not make much of a difference, but every little bit helps.

 

[spangenb]

I'd get that ethanol free for my lawn mower or my Jeep Comanche, but that's about it.

Now ethanol free 93 I might be able to get behind. Here they only carry 91.

 

[WScottCross]

I could only find 89 ethanol free. Personally, for Autocross I'm going the other way and running E30 or E40 with a tune. For milage, E0 might yield a slight benefit, but not worth the extra cost IMO.

 

[razorlab]

There is a station near my house with ethanol free 93 octane. I do my best to stop in and gas up there before autocrosses. It may not make much of a difference, but every little bit helps.

Wait, wut? If you care about performance, you want ethanol, not ethanol free...

 

[Mr UFO]

Was told by a tuner at Cobb Surgeline that gas with the 10% ethanol mix is much more resistant to detonation. Makes sense from a performance standpoint.

 

[Cligedy]

The only advantage ethanol has is a high octane rating. E10 doesn't have any additional octane over regular pump gas, plus, pure dinosaur juice has more energy by volume than ethanol.

 

[razorlab]

The only advantage ethanol has is a high octane rating.

Incorrect and that is just ignorance talking. It sounds like you are just another anti-ethanol type of person so I won't even attempt to have a conversation around it with you.

 

[Cligedy]

Incorrect and that is just ignorance talking. It sounds like you are just another anti-ethanol type of person so I won't even attempt to have a conversation around it with you.

Sorry, I haven't studied up on it. I wasn't trying to argue or be a dick about it.

 

[WScottCross]

Sorry, I haven't studied up on it. I wasn't trying to argue or be a dick about it.

I was of the same opinion until pretty recently. The higher energy density part is true from what I understand, I could be wrong on this and I hope razorlab will enlighten us both since he has been tuning cars for higher ethanol blends. My understanding is that you could potentially get higher MPG from E0 gasoline, but better power delivery from higher ethanol blends with the right tune. Do I have that right razorlab?

 

[coffeeslug]

I only have 91 in my area, and I can go to a station which has it with 10% ethanol or to a station that has it ethanol free. I always go for the ethanol free when I can and get 1 mpg more from it. If I had 10% ethanol 93 available as a sole option over 91, I'd certainly buy it every single time. But if I had a choice between 10% ethanol 93 and ethanol free 93, I would get the ethanol free simply because the performance is the same and the mpgs are greater.

 

[WScottCross]

All of the ethanol free gas I have seen is MUCH more expensive than E10 in the same grade. I tried it and got slightly higher milage, but not enough to justify the cost. If you can get it for near the same cost, it may work out for you.

My custom E40 tune get me almost 20 HP increase over the OTS 93 Cobb tune. It's a pain to mix the fuel since I have to stock up and store 5 gallon cans of E85 and mix it in the tank before an autocross, but the gains are worth it for me.