Keigo

Lots of people say they only run the Scoobies on Optimax or Super Unleaded. is that purely for performance? I know Japanese ones need to run on richer fuel, as their ECU tells them so, but for UK specs, is it really necessary?

k9any

I felt that optimax made my car run a lot smoother and was more responsive....didn't give me any more boost though.

MY97 UK WAGON

nom

Well, the Euro spec cars are set up for 98RON. They are/were sold in the UK for 95RON, as it's much harder to sell a car that only runs on SUL (or rather, above SUL ).
But the ECU will cope with NUL (95), the car just won't be as quick, will run rougher, etc. I think I'm not on my own in thinking it's worthwhile spending the little extra cash on SUL over NUL - seems a shame to not use it.
Most definately steer clear of supermarket stuff. It can be really quite iffy... for anyone who doesn't think it's a problem, watch your KnockLink after filling up with the stuff Even if the ECU can pull the timing back this much, the resulting performance would be appauling! I had no choice a while back but to use this stuff (had run out of octane booster too - d'oh! ) and even driving like a nonce after seeing the KnockLink, the ECU had gone into 'panic mode' & I had 'actuator only' boost (ie almost none ).

greasemonkey

Don't generalise too much about supermarket fuel. There's nowt wrong with the Sainsburys SUL that's available round this neck of the woods