I have just bought my first mini being an '03' reg mini cooper s, 6 speed. I have had the car about a week and at first i was putting the higher octane fuel in it from shell and bp but the latest refuel was at asda and i just put normal unleaded in it.

I dont know if im imaging it or if i have just got used to the cars power but i cant help but think the car isnt as quick as it was when i first got it.

Could it be the fuel or is it likely to be something else. Should i take it into the bmw garage and get them to run a diagnostic or something???

Cheers.

 

It's the fuel. Anything less than 91 and it will start to pre-detonate and pull timing. Just fill it up with 91-93 next time and it'll correct itself.

 

I tried the lower octane and not only less power but signifigantly less MPG ...
Really not worth the 20 cent savings ...