jaybertx

So I found a gas station close to me that is selling 90 octance, ethanol free gas. They have to sell it as "recreational fuel" as its apparently illegal to sell anything but E10 in Florida.

So here's the question... am I better off with 93 octane E10 or 90 octane E0? All opinions and experiences are welcomed!

Ltngdrvr

Either one will work, probably make more power on the 93 E10 but get better economy on the 90 octane non-alcoholic.

What's the difference in price?

AzPete

There are three of those stations around here. I have found it not worth the price difference in new cars. Now, when I had the classics, that is all I ran.

jaybertx

It's about .25 more per gallon. I'm more concerned with the performance than the economy -- even though it's a DD I only have a 6 mile round trip commute to work.

If I still had my boat or the car was going to sit for a long time I'd go E0 but thanks for reinforcing what I felt was right.

RyleyinSTL

In that case, run the 93, end of story.

steve03gt

Stock car likely doesn't need the extra octane, unless extreme temperatures where it would be reducing timing.
I'd go for the 0 Ethanol.

I run (Im in canada) Vpower 91 w/ o Ethanol, over the 94 at Petro w/10%
Ethanol (from what I understand) Is a filler, so less power, less economy

AzPete

I never noticed a great power boost in the seat of the pants. Also, at a quarter a gallon more, the addition mpg's have to be pretty high (but then again I never did a scientific test).

steve03gt

In my case, the 0 Ethanol is cheaper than the higher octane, so its an easy decision for me. In most cases you wont feel anything in 93 over 91.

WhiteBird00

Gasoline has the same amount of energy regardless of octane rating. However, ethanol has about 34% less energy by volume than gasoline. So E10 has 3.4% less energy than pure gasoline.

I don't know the HP rating for the 5.0 using 90 octane. The rating is 412 using 91 octane and 400 using 87 octane. Even using the 87 octane 400 HP rating and adding 3.4% for pure gas gives you more than 412 (413.6). Plus you get better 3.4% better mileage.

Those calculations don't take into account the performance benefit of higher octane that is created by the ECU advancing ignition timing. I don't have any specs on that so it's almost impossible to guess which fuel would give better performance in the real world.

Big Poppa

My concern is will this stuff harm the engine later on after prolonged use?

AzPete

It should not hurt the engine.....it is the newer crap that can do damage....especiall if you park the car for the winter season.

If my figures are close, the 3.4% thing gives you .85 mpg more if the car is getting 25 mpg. So, one tank will net about 12 more miles distance on the highway....for an additional cost of $3.50-$4.00 per tank. One hard acceleration and all that savings is out the door....

At least I think I figured correct.....based on a 14 gal fill up.

kcoTiger

FYI, re: fuels, I spoke with one of the folks at SVT and they told me the GT500 engine will be just fine with 10% ethanol and won't suffer at all if it's run on it. He also mentioned the 5.0 was made to handle the ethanol as well, which means it shouldn't cause anyone any problems if they run E10 fuel through their Mustang. I would imagine this is pretty much status quo, since I know Ford has their eyes on building cars for the much more restrictive CAFE limitations in the future.

WhiteBird00

E10 (and any other ethanol blend) has nothing to do with CAFE standards. Quite the opposite, auto manufacturers would be delighted if ethanol would go away because it would make it easier for them to reach the CAFE requirements. Adding ethanol to gasoline reduces mileage in direct proportion to the percentage of ethanol to gasoline.