XSeries-forum

I always run my X5 on normal unleaded but just put some 97 octane in and it definately feels better,any thoughts on this,mpg etc?

The difference in cost per litre isn't worth it.  Same with the Super Diesel.  Unless your vehicle really needs it - and most don't - you are doing no more than emptying your bank faster.

I reckon that I get around 10% improvement in mpg so for me if it's more than 10% dearer per litre it's not worthwhile.

Car gives best mpg when up to temp.

Incidentally mine seemingly runs best on 97 octane as opposed to 99 octane. I think engine runs best 95-97 according to literature and sticker in fuel lid.

I reckon additives may help engine care too albeit more benefit probably by me generally keeping revs sensible when cold.

Placibo effect probably a factor too

i think my ml63 runs on 98 oct better in mpg but as said above the last time i looked there was 23ppl differeance near me, so i just put standard in, on my cap it says recommended 98ron, min 93ron so i pressume standard 95ron is fine

[quote="shadrack"]
i think my ml63 runs on 98 oct better in mpg but as said above the last time i looked there was 23ppl differeance near me, so i just put standard in, on my cap it says recommended 98ron, min 93ron so i pressume standard 95ron is fine
[/quote]

95 only if 98+ isn't available.