Pretty sure the highest unleaded race fuel on the market is 105 octane and that is the VP MS 109.

 

a 2 second google search - http://mbworld.org/forums/showthread.php?p=2697755

 

alright, everybody's response is acknoweledged. BUT... i do have a choice of running 92 from super america (who knows what the hell they put in it, i.e. crap tons of ethanol) or i could run whats called " neat 91" which is pure 91 octane without any additives.
http://www.firstfuelbank.com/products/default.asp
thats the link to the local fuel depot. is that stuff better to run than 92 from sa? i am mostly concerned bout the car here. i dont really care about performance gains, just makin sure the car gets what it needs

 

If it's at the race track, it usually is. Even if it says "unleaded," it often has lead in it due to contaminated pumps. Less than 5 gallons and 20 minutes with this stuff will destroy a cat. Trust me!

Even if it is actually unleaded, high octane gas will have such a slow burn that it will actually cause a less efficient burn, loss of power, end will eventually still kill the cat. A stock computer can only push the timing so much so 110 octane is useless in a street car without a lot of mods and tuning.

Where do you live that finding regular 91, 92, or 93 pump gas is an issue?

 

i am from st. cloud minnesota. finding 91 isnt really an issue. i know a few stations around here that carry that. but i would rather run 93 cause i would assume its better because as per my gas cap that is 91 is the MINIMUM. i dont really want to hurt the car by running inferior gas.

 

the reason i am so concerned is because my sled calls for 87 ONLY. i ran 91 in it once and it ran like obsolute ****. it is an efi (if there is any sledheads on here. its a 99 arctic 500 efi). i dont want the same thing to happen to my audi. i would much rather spend an extra few gassing it up than having it run like **** to save five dollars

 

Your sled (I'm assuming snow mobile) most-likely does not have OBDII controls that take into consideration things like knock and post-cat O2 sensors, so it wont push timing radically like your Audi. High octane gas in a vehicle tuned for 87 will run poorly due to the elongated burn time.

Believe it or not, your 1.8T can run on anything from 87 to 93. It has a knock sensor and many controls to allow it to perform on anything from crappy CA gas to Sunoco 93. In stock form, the car will run on 87, but throttle response will be a bit sluggish in comparison and acceleration and MPGs might be down a bit due to the retarded timing. If you get really crappy 87, the knock might get so bad that is starts detonating, destroying, misfiring, and throwing codes of all sorts. In stock form, however, you won't get the most out of 93 because of the factory mild boost setting.

Use 91-93 where available. If you have a chip, 91-93 is really a must to prevent MILs.

 

your fine running 91. thats all i got here and my car runs like a champ. if your worried to much about it, spend the money and put a octane booster in every time you fill up...

 

^^^word. but... that stuff only increases octane by one point if that. i guess my new question would be is it okay to run sa's 92 octane (which i am assumin ethanols is mixed in with) or would it be better to run that neat 91 with NO ethanol in it. to make matters more complicated, the neat 91 is bout .50 cents more expensive....

 

my dad has a polaris RMK 800 vertical escape and he runs 90 somethin in it and it runs like a champ
but its piped ported polished and snow checked every year so yeah