hapa

Who knows of stations that have higher than 91 Octane out there? I usually just gas up at Shell, but am curious in the Ottawa area where you could find some 94 or maybe 96 Octane? I know that it gets hella expensive, but was wanting to try a tank to see what difference it made if any.

wing

Sunoco has Ultra 94.... so find a Sunoco and your all set.

Terence

You can get 94 @ Sunoko.

http://www.sunoco.ca/

It's not that much more expensive than 91. I put that in whenever it just so happens I need gas and I see one. I use Esso most of the time just cuz that's the closest to my house and there's one beside my office. The speedpass is great too.

I'm contemplating whether I should switch to Petro after reading an article.

http://www.vettenet.org/octane.html

Triple-H

I'm not convinced there is any reason to run octane higher than 91.

Around here I can not find 91, only 93 and 94. When I was up for the Slamander I ran '91 because I could find it and the car seemed the same to me.

Fongu

Yeah, you don't need more than 91 unless you're car is pulling back timing because of knocking (pinging). Supposedly, we can run on 87 with reduced power (although I never tried it).

That being said, I just put 94 in. I like to have when tracking or for autocross, which are typically very hot. Couldn't be bothered with timing the tanks of gas to save a few cents. You can save more by buying on Sunday and Thursday. Check out the price stats here.

http://www.ottawagasprices.com

hapa

I have heard one of my customers Drummond's has one station has 102 Octane or something...i was just wondering where else you could get a +91 and if there was anything more than 94. I really don't think there is any difference in 91 to 94 octane. i wonder what 100+ would do to the engine, and how it would run?

Fongu

100 is race gas territory. I don't think it's harmful if it's unleaded. FYI lead increases octane.

Unless, the engine is modified, via higer compression or high boost, having higer octane isn't helpful. Just having higher octane (higher anti-knock) doesn't generate more power without an engine that can take advantage of it.

hapa

so by saying that for Gropos's with his SC the higher Octane would be more beneficial for him over us?

Fongu

I think the "stock" supercharger is designed to work with "pump" gas which is 91 in California. That's ~7psi boost. I think they are basically eating into the safety margin that Honda builds in. The supercharger also runs richer air/fuel ratio, to keep combustion temps down to reduce the chance of knocking. Blah, blah, but the higher octane would give more safety from knock in hot weather and/or hard running.

It is easier to tune a supercharger for more power, by getting a smaller pulley to up the boost. If you know you are going to run race gas, you can increase the boost (more air and fuel, more bang, more heat, more danger of knock) and still be safe.

For a turbo car, all you have to do is change the pressure release setting on the wastegate to up the boost. (Ok not that simple)

For a NA car, you have to increase compression ratio, bore, stroke, increase rpm, do head work, etc. All are basically engine rebuilds. Not something you can tweak in a hour.

hapa

ahhh engine mechanics...I'm not a whiz when it comes to the mechanics of engines, but I am always interested in learning about how it works and why? I was pondering which mods to do to increse HP and performance. The jury is still out on what I will start with