GTC

So I've started driving a few miles to fill up in order to buy a Phillip's 66 station's ethanol free premium (93 octane).

$4.79 *Ouch* a gallon.

Can you guys tell a difference when you run this stuff?

cruisin5268d

I think the general consensus is that you cannot tell the difference between fuel with ethanol and fuel without just by cruising around the streets.

GTC

I figured. Thanks, I'll save myself the $60 fill up next time.

jz78817

in power? No. In mpg? maybe. I'm fortunate enough to live aside the Great Lakes where the marinas all sell ethanol-free gas (carbureted outboards hate ethanol.) I've been considering filling my car up for a couple of months on their no-ethanol 93 and seeing what I get, even if it's an un-scientific test. Even if it's $5.20 a gallon.

where it does make a difference is in my R/C boats, and by "make a difference" I mean "carb diaphragms last more than a couple of months."

MrSandman

I get noticeably better MPG with ethanol free gas. Problem.. there arent any stations selling it in 93 by me. My parents have one by them.. and they live 80 miles away. I started to notice that I get way better MPG driving home from their house then driving there, lol. I started to keep track of it, and I get about an extra day on that gas.

GTC

Give a number - from what mileage with ethanol to what mileage without?

Thanks

JIM5.0

As already said by another, no, you will not know the difference in BHP.
E10 (pump gas with ethanol, 10% ethanol, 90%gas) will give a very slight HP boost only if you slightly richen the mixture to exact stoichmetric fuel-air ratio, but you will not notice that unless you are on a very accurate dyno.

I can tell you from my own experience that E10 does give you a lisght boost in preventing engine knocking on a spark advanced tune with a very high spark tuning table, but you have to be watching your tach very closely and listening to your engine very closely to know the difference.

Also, E10 slightly lowers your MPG, but you can only notice it if you are calculating your MPG aver a 2week or longer period.
Ethanol hurts MPG because you have to use more of it to make the same combustion force as a smaller amount of non-ethanol gasoline can make.

JIM5.0

Speaking from my own experience, this is what I have observed between E10 (required ethanol) vs E-Zero (ethanol free).
I have this direct experience because during the winter, ethanol is not required so the gas stations sell ethanol free gas, but during the summer, E10 is required and the very same gas stations sell that.

Not considering air temps between summer and winter or when I drive spiritedly vs like a grandpa, this is my own numbers I have observed:

E-Zero (ethanol free): 16gal tank at 380 miles range, best observed
This is averaged to 23.75 MPG

E10 (summertime gas): 16gal tank at 315 miles range, worst observed
This is averaged to only 19.69 MPG.