Tesco Super Unleaded

[MrBet]

I've always filled my E92 M3 up with Tesco super unleaded that says it has an octane rating of 99. In the manual it says use unleaded between octane ratings of 95-98. Am i doing anything detremental?

How do they increase the octane rating? Is it just an additive they put in the fuel.

[MrBet]

I think you have to be using the same ron petrol for a few tanks for the ECU to adapt to the different grade fuels.

I used to have an S2000 and you could really tell with that. There was much more of a kick on the VTEC with the super unleaded than the standard.