Does it reallly matter if one uses regular unleaded gasoline or should I use a better grade? I bought a 1987 240 dl volvo which lasted me 14 years, and I used regular unleaded for all 14 years. Now I have a 2003 S80 (not a turbo).

 

Well I know for at least the Volvo turbo models they say to use Premium octane. And yes it does preform much better. However running regular gas is just fine. I do it all the time in my car.

My car runs better on Premium gas but it runs just fine on Regular. Also @ $3.25 a gallon for regular and lets say $3.45 a gallon for premium the difference per tank in my case is only, $4 or $5 a fillup. Now yes in this day and age money is tight and gas is killing our wallets. However if you have any doubts as which to use and cost is a factor then just read what I have just stated.

 

I second the use of premium. When I first got the Volvo I was still using 87 in it but later switched to 91, sometimes 93 if I find it at a station for cheap. I've noticed smoother starts, better overall performance, and better performance in particular during acceleration.

For an 850, the minimum is 91. If you've got Sunoco in your area, they should have 91. Usually it's a better deal than what anyone is offering on 93 but check around--sometimes you can find the better grade cheaper.

I didn't notice any difference in mileage with a higher grade. I'm not overly concerned about price difference; around my area the difference between 87 and 91 is anywhere between 12 and 20 cents at most stations and since my mileage is usually pretty low it's not too bad, maybe a difference of $5 per month or so.