Octane rating vs. fuel mileage which is best?

[91cavgt]

Octane requirements also vary with atmospheric conditions. A car may knock and ping on 87 octane in the desert in the summer going up a steep grade, but 87 octane maybe too high in the winter time at high altitudes.

[cyclopathic]

Octane requirements also vary with atmospheric conditions. A car may knock and ping on 87 octane in the desert in the summer going up a steep grade, but 87 octane maybe too high in the winter time at high altitudes.

Many states with higher altitude Colorado, South Dakota, Wyoming, etc sell 85 as regular.

[Timinator]

To resurrect a old thread: (im sorry) I tested my low grade fuel, 87 E10 vs 90 E0. I gained about 4 mpg and some part throttle performance with the 90 E0, which is currently 1 cent cheaper than 89 E10 and 40 cents cheaper than 93 E10

[stevedmc]

I can't speak for everyone else's car, but my car is fuel injected. The fuel injection system has a fancy-schmancy computer that automatically adjust the fuel-air ratio based on what the car needs. 87 octane gas works just fine in my car and I have 210,395 miles on the car to prove it. If anything, you should do a fuel system treatment every once in a while to keep your fuel injectors clean. I use concentrated Techron.

[Fummins]

To resurrect a old thread: (im sorry) I tested my low grade fuel, 87 E10 vs 90 E0. I gained about 4 mpg and some part throttle performance with the 90 E0, which is currently 1 cent cheaper than 89 E10 and 40 cents cheaper than 93 E10

So you're saying 90 octane without ethanol is cheaper than 89 with 10% ethanol? I wouldn't doubt ethanol hurts economy but I agree with steve saying there's no point in running anything but 87.

I've never been able to tell a difference between different octanes. I don't have the patience or time to run a few tanks of pricier fuel then drive exactly the same road at the same speed everyday. Plus there are too many variables for me, rain, wind, snow, traffic, towing, road rage etc...

[stevedmc]

So you're saying 90 octane without ethanol is cheaper than 89 with 10% ethanol? I wouldn't doubt ethanol hurts economy but I agree with steve saying there's no point in running anything but 87.

I've never been able to tell a difference between different octanes. I don't have the patience or time to run a few tanks of pricier fuel then drive exactly the same road at the same speed everyday. Plus there are too many variables for me, rain, wind, snow, traffic, towing, road rage etc...

Using a fuel with a higher octain rating that what our car is designed for will just result in increased carbon deposits.

Now, there is a difference between ethanol and non ethanol fuels. Our cars are designed to run fuel with up to 10 percent ethanol without causing any damage. In a dream world, you could still buy 100% pure gasoline on every corner without a crazy markup in price. 100% gasoline gets better gas mileage than gasoline laced with corn.

In the Delorean, I try to only put real gas in it. In the Mirage, I settle for the corn stuff since the car was designed to run it anyway.

[Timinator]

The increase in octane, be it 89 or 90 is a pronounced better performance over 87, my car doesn't jump like it does on 87

[Cobrajet]

I just filled my car up with 92 octane E0. Will let everyone know if I see a huge difference.

[Eggman]

I filled up with 89 octane once and saw no difference in operation.

I know of no process or method these cars use to detect octane levels in a tank of gas.

[Cobrajet]

I filled up with 89 octane once and saw no difference in operation.

I know of no process or method these cars use to detect octane levels in a tank of gas.

It's the 'E0' part that I am curious about. I filled this thing up with 92 octane E10 and saw no real difference.