View Full Version : 91 And Octane Booster?

06-09-2003, 12:25 AM
i filled up the other day with 91octane, as there was no better gas available at that time, and the car seems to run like ***(sputtering or something) and i was wondering if it would be a good thing to add some octane boost? what kind if so?

i also dumped in a bottle of tko2000 fuel system cleaner as i thought a dirty injector might be the problem or something.

06-09-2003, 07:31 AM
I spent a while looking at the various kinds of octane booster. The most improvement in octane you can expect from one of the bottles is 3 points which translates into .3 octane... so if you were
lucky you'd end up with 91.3 octane. Probably not worth the hassle. You'd be better off mixing in a gallon of 100+ racing fuel if you wanted to improve the octane quality.


XR7 Dave
06-09-2003, 11:00 AM
Don't know where you live, but most SC's will run ok on 91 unless you are running a lot more boost, but I think you said you had only about 9psi of boost? More than likely you just got some bad gas, or your vacuum leak is getting worse.

Aaron Pedroza
06-09-2003, 11:05 AM
Toulene and xylene are good octane boosters. Take a look at the link to see how good they work. I would avoid the alcohol though, it will dry up and eat up gaskets and seals quick.


06-09-2003, 01:34 PM
In Minnesota, all our fuel has alcholol in it in the form of ethanol. Most of our fuel has 10% ethanol by volume.

Only the 93+ octane at some stations is, what they call, non-oxygenated fuel. Mostly found in rural areas close to lakes for use in boat motors mostly but also in areas where residents have asked for the fuel, typically used in collectors vehicles.

The point is that alcholol by itself should't be a problem if not used in too high of an amount.

Aaron Pedroza
06-09-2003, 02:02 PM
Ethanol is much less corrosive than Methanol so it can be used in smaller concentrations without a prob. The problem is trying to find Ethanol at a reasonable price, Methanol is much easier since it is a common racing fuel. Isospropyl is probably the least corrosive but the way we buy it, it would have as much as 30% water in it. If you buy it any other way it gets expensive. I just use racing fuel but have used toluene with good results.

XR7 Dave
06-09-2003, 07:17 PM
It seems to me that mixing gas to put in your daily driven street car is silly. Besides being a pain in the butt, how do you know that you have it mixed right all the time? Not to mention that the adaptive strategy of the EEC is going to be all screwed up from seeing different types of fuel in there all the time. Do yourself a favor and don't bother. If you are having detonation issues due to poor gas, then pull the octane plug or better yet wire it to a switch so you can have cockpit controlled timing adjustment. If Chris Wise can make 390rwhp with pump gas then none of the rest of us should really need race fuel. :rolleyes:

06-09-2003, 07:32 PM
I dont think 91 octane would cause the car to run bad like that.

Out here in Seattle, 92 octane is the highest available, and it's all I've put in my car since I've owned it. Not a problem anywhere.

06-09-2003, 09:19 PM
I drove my car home from out of state with a full tank of gas. During the trip, I noticed a very slight pinging type noise, almost too quiet to detect. When I got back & refilled the by then empty tank with Ultimate 93 octane, I realized the previous owner had used 87 octane gasoline. This was a long trip. As you can see, there was little difference, execpt for a tiny bit of power & a little noise.

This is not to promote running lower octane fuel, as that would be bad. But rather, it denotes that the degree of trouble you are mentioning is probably do to another cause; perhaps even one made worse by lower octane fuel.

Thomas A
06-10-2003, 01:09 AM
Gas with Ethanol (E-10) is actually cheaper here. Of course, that might have something to do with the fact that I live in Nebraska :D


now a tbird guy
06-13-2003, 04:00 PM
We have 94 octane here :D