Quote:
Originally Posted by lukesforester
Hey i just got my forester, I've heard there 10:1 compression ratio.
To me that seems high so would i get better mpg and or better performance from higher octane gas, 89,91 or even ultra94... i work at sunoco lol  |
That is what's specified, and going to a higher octane will give you zilch in terms of a performance improvement.
There are *some* cars that will tune for the range between 87 and 91 or 93 octane--my son's '97 BMW 318ti (four cylinder) recommends premium but is completely OK to run on regular or midgrade. I believe that the 6-cylinder Outback is the same--recommends premium, but will run on regular with slightly decreased performance.
But if a car is designed for regular, it's fine on regular. I believe my wife's '07 Honda Civic has a 10.5:1 compression ratio, and regular fuel is all that's required.
If you work at a Sunoco and get gas for free, or if you don't have to pay any more for higher octane, you could run it on 89 or something like that, but you really don't need to.
George