Hey there, i bought a 1999 c70 used but it doesnt't have the manual i got it at 90,000 miles got an oil change and everything done(bought it from a guy working for my dad he upgraded to a 03 volvo) anyways ive used 87 octane for a month or so now i jus got an oil change done to it so i jus wanted to get a fresh start kind of and know which octane is best for it? which gas station you guys would say is the best quality? Any help would be great. Its one of those things thats not a huge deal but is bugging me a lot!!
I just wanna know which octane is the best.(well obviously preimum is) but its an 99 so like is it neccessary is 89 octane good enough etc?
any help
thanks

okay, first, is it turbo? if so, more octane is better. if it starts knocking (hopefully it hasn't) go higher in the octane. understand that you will hear all sorts of advice. it will run at a lower octane, but the full amount of power won't be shown until you go for the higher octane levels. all my cars run 97+ octane, heck the impala runs 101 octane when i can find it. my 850 R can and has run on 89, it doesn't like it and neither do I, for the full boost, i use 97 octane. so the call is yours, if possible, run the highest octane you can find and see what the difference is and then decide yourself. good luck and post your findings.

well i dont know if those octanes are neccesary those are really high, and again its an older car but it has turbo which made me think twice. Right now im using 89 octane, which is mid-grade (up here in canada at the shell) is shell the best gas station u'd say?
anyways any feedback woiuld be nice. is 89 fine? for a 99 vovlo c70 at 99k miles or is 91 needed..etc

I use 91 in Toronto Canada. Those other 97+ octanes can't be the (r+m)/2 octane ratings otherwise it's race fuel which is not cost effective. The owner's manual for our cars recommends 91 octane.