I've always filled my UK Impreza up with Optimax because it's 98 RON and was wondering if it makes much difference on a UK car over standard fuel?....

The only reason I ask this is because it's a pain in the **** travelling to the nearest Shell garage which is miles away and not on any of my routes. For example I'm on empty now, and got to drive from work to this garage which is 20 miles away just to fill up!...

Would it make much difference going back to normal unleaded or could it lead to detination in the engine?... Should I just stick to Optimax and fill it to the brim each time?...

Matt.

 

I used to use NUL and the only difference is a bit more hesitation when you're trying to boot it. Oh and it pops and crackles loads more. But the Shell garage 100yrds from my house has just decided to stock optimax, so I guess I'll use that now i don't have to go 10miles+ out to fill up...

Andy

 

Yes it will likely det more. Do you have a knocklink to tell?

I noticed a big difference just going from Optimax to BP's Ultimate.

Guess it depends if you drive/rev it hard. If you potter around below 3000rpm I doubt it would kill it.

Stefan

 

UK cars will run fine on 95RON unleaded, they are mapped to cope with this, however the performance may be a little less, as over time the ECU "learns" how to take advantage of the higher octane, by altering boost, ignition advance etc. Why not use super UL from any other source, after all that is 97 RON and may not be so out of your way.

 

UK cars can cope with lower quality fuel better than the JDM cars, but they can still det, and generally don't run as nicely (or as economically) when run on "premium" unleaded.

If you don't want to go out of your way for Optimax though, other refiners' Super Unleaded gets you pretty close - certainly closer than most of the 95RON you're out to find...

 

Thanks for the reply guys, I guess I'll just start using a mixture of SUL / Optimax depending where I am etc. I'll go for Optimax if I can as thats 98 RON.

 

I use esso super unleaded, i find it a lot smoother and more mpg than optimax, but thats my opinion