Octane.....

[DRWWE]

No I'm not asking if it's OK to use lower grade gas. We have 91 octane gas in California. I see on the site that some of you use higher grade gas than 91. What parts of the country have 93+ octane fuel and do you notice any improvement over 91. Are emissions any different? Performance?

If emissions are higher that might explain why CA has only 91 octane, but then there are not really good explanations for most things in CA.

[driving2]

 

[selavia]

I'm in Baltimore, Maryland and are grades are as follows:

Regular: 87 Octane
Midgrade: 89 Octane
Premium: 93 Octane

Sunoco has a fourth though:

Ultra 95 Octane

I use either 93 or 95; I've used 89 before. Don't really notice that much of a difference. Any difference I think I notice, I attribute it to being in my head.

Sean

 

[Big Daddy]

Washington state the norm for premium fuel is 92 Octane.

 

[MrElussive]

In NJ our Premium grade fuel is typically 93 octane. Some less expensive gas stations use 91 octane for their Premium fuel.

 

[epj3]

PA is the same as the rest of the north east.

 

[jszar]

higher octane is for higher compression. there is a limit i believe, like its not a good idea to run 100 octane in a car engine. 100 octane is for airplanes and helicopters, which have small eninges but run at high compression.

 

[codex57]

higher octane is for higher compression. there is a limit i believe, like its not a good idea to run 100 octane in a car engine. 100 octane is for airplanes and helicopters, which have small eninges but run at high compression.

With that in mind, some 76 stations sell 100 octane race gas. You could give it a try. I don't think one time would cause any permanent damage. Don't quote me on that tho.

 

[Average Jae]

the great debate about octane: some say you don't need more than necessary. true, but my unscientific testing has shown that i get lil better milage when on higher octane stuff.. (almost offsets the 10, 20 cent difference..) but it is supposed to not matter, and if your car only requires an 87 octane rating, you just maybe burning a buck or two or three per fill up. who knows..

if your car requires having premium (octane rating in the 90s) putting in regular or plus is supposed to degrade the performance of your car. it is because higher performing engines usually run hotter, and octane rating basically is how much heat the chain of carbons can take before breaking up, releasing the energy. w/ the lower octane gas, it prematurely "burns up" or breaks up before getting into the compression chamber? thus the engine can't get the most power output. back in the 70s, the premature burning caused a knocking sound. the modern engines have what they call a knock sensor to detect this, and retards engine performance (to drop engine temp) to ensure that the fuel does not pre maturely burn.

 

[Kirby]

In my area Sunoco sells 87, 89 and 92; Ultra is 94 octane.

 

[selavia]

In my area Sunoco sells 87, 89 and 92; Ultra is 94 octane.

Really? See I was in VA the other day and I stopped at a Sunoco and Ultra was 94 too! I wonder if I've been reading it wrong at Sunoco here...I'm going to have to stop by tonight and see.

Sean