legacycentral bbs

I have a 92 Legacy FWD Auto. and this car has seen nothing but 93 octane all its life.

I wonder what you guys use in your cars and if, at any you see any performance gains and/or losses?
Please specify your model, year, transmission.

Thanks

You should try a few tanks of 89, you might actually get more power.

In hot weather under heavy stress the 93 would help, but at other times you may loose a small percentage of power because the slower burn.

I always use 92 in my wagon, and 89 in both my sedans. I also have my mom use 89 in her sedan.

So Ciper, where are you getting this mysterious 92? The highest grade I've seen anywhere in California in the last two years has been 91. Other than race gas that is.

-Brian

Another octane question, I plan on doing some drags soon and was wondering about the race fuel. The track I'm going to has a bunch of different grades.100 GT plus, 104 GT plus, these may be unleaded then 110, 112 and 116 octanes which definitely are leaded. Are the leaded fuels ok to run if it's only a few gallons at a time or not? I will only be running one 3" high flow cat in the midpipe location. Thanks

eastbaysubaru: Im not, that was incorrect. I keep forgetting how crappy the gas is in CA!

Im using 91.

Because I am not a cheapskate, I ran 93 octane (what we get here in FL) for a couple years actually.

Upon Legacy777's suggestion, I tried a tank of 89 octane, and have not gone back since. It is simply better in every way. So I vote that 89 octane is the best to run in a factory engine setup such as mine.

I use 87 and have had no problems at all (N/A fwd). Higher grades seem to make no difference, but I did have trouble when I cheaped out in the desert with the expensive 85 (!) octane they had. That's what happens when you drive cross country to the Monterey Historics week on a rail-road-track-flattened dime. So no lower than 87, I'd say, especially if you have to climb mountains.

Steve

So nobody knows anything about the race fuels?

I wouldn't run the leaded fuels, why screw around with something that could mess such expensive stuff up for possibly a few extra hundreths of a second. Since you are in PA I assume you have access to 93. I would run a couple of gallons of 93 and mix that with a couple gallons of 100. The hydrocarbons and whatnot are better burning in these race fuels and will offset the wussy stuff that is in mass-consuption fuel. Or something like that. And your ECU will find that advancing the timing is not setting off the knock sensor and you'll be ready to roll.

Shouldn't he worry about the cat if he's running race, or any leaded, fuel??

I actually run sunoco ultra 94 all the time,currently 1.64$. If the GT fuels are unleaded I may run some 104 but will stay away from the leaded. I figured I probably shouldn't run any leaded. Just want to put in some good runs and represent

You can't run leaded fuel through a cat. High probability of melting it from what I have heard.

This may be of some help.
http://www.repairfaq.org/filipg/AUTO/F_ ... SOLINE_010

5.2) Why are there seasonal changes?
Only gaseous hydrocarbons burn, consequently if the air is cold, then the fuel has to be very volatile. But when summer comes, a volatile fuel can boil and cause vapour lock, as well as producing high levels of evaporative emissions. The solution was to adjust the volatility of the fuel according to altitude and ambient temperature. This volatility change has been automatically performed for decades by the oil companies without informing the public of the changes. It is one reason why storage of gasoline through seasons is not a good idea. Gasoline volatility is being reduced as modern engines, with their fuel injection and management systems, can automatically compensate for some of the changes in ambient conditions - such as altitude and air temperature, resulting in acceptable driveability using less volatile fuel.


Well it's always nice to know why your car will always run crappy once you get into certain parts of the country.