High Octane Fuel

[A.J.]

Here in Montreal we have 3 grades of gas: 87, 89 and 91 octane.
I noticed that the pump says that 87 and 89 "may contain up to 10% ethanol" but there is no such label on 91.

While I heard that higher octane might not give a boost in FE, I was wondering, would there be any advantage of driving on 91 (E0) rather than 87 (E10)?

Thursdays, the difference between 87 and 91 is only 11.4 cents/gallon rather than 22.8. Do you think it's worth it? (keeping in mind gas here is about $5.14/gallon)

[Ladogaboy]

The only advantage is if your engine is tuned to run on higher octane, or if your engine is experiencing knock due to timing while running a lower rated gas.

[Ryland]

Best way to find out is to try it, some people see an increase in mileage when they use pure gasoline and some people don't see a difference.

[gone-ot]

...99% of the time, use 87-octane per manual; but (1%) will up it to 91 or 93-octane when heavily-loaded and driving in hilly country (Colorado).

[mort]

E10 has about 3% less energy than gasoline, but your price difference is about 2% so I'd say you could save money by buying premium, if it really is pure gasoline. But I bet it isn't. I bet the increased antiknock rating comes from MTBE, which also has less energy than gasoline, but more than ethanol. So you're probably breaking even.
-mort

[slowmover]

Stick with

[dkunitz]

My '03 Kia Rio's mileage would dip by about 3% MPG when I used 89 instead of 87. So I stopped using anything other than 87 even if a station sold 87 and 89 octanes for the same price. However, I think all of this was before E10 appeared.

[gone-ot]

...yeah, I remember the "good old" premium high-test SUNOCO 260, wish it was still available here in Arizona.

[slowmover]

Originally Posted by Old Tele man

...yeah, I remember the "good old" premium high-test SUNOCO 260, wish it was still available here in Arizona.

And the T-Rex of the American Interstate. The phrase can't outrun a radio had no meaning when the LEO's had these:

http://assets.hemmings.com/story_ima...00-0.jpg?rev=2

Todays supercars might have more top end, but it's meaningless without the open road of yesteryear.

As to todays cars and fuels, mid-grade seems to work well for the additive package (fewer fuel-related problems on small-engined equipment as the test).

.

[mcrews]

I have done several 'tests' while taking my trips to Texas from CA.
My car is one of those that says '91'.
It does make a difference in mpg if I drop down. according to the scangauge, the ign advance drops down.
Whoever in othere threads (ignoring the ethonl) going up to 91 from a car that is supposed to run 87 didnt help.

But I think mort might be onto something in his post.