Running a car mapped for v-power on something else?

[Stu_182]

I had my car mapped at RS tuning and it was mapped for v-power and that's all I've ever used since what would happen with if I used another high octane petrol? Or a lower one?

 

[Chip-mk1]

Assuming the other petrol is a similar standard (not just RON to consider but thats the main thing) then it shouldnt make any significant difference.

If you run a lower RON fuel it will increas the burn speed which in turn could lead to detonation, if the knock sensor catches it you'll just get a bit less power, if it doesnt it could melt your engine.

Depends how far safe your map is in the first place though, at most load sites TBH it will probably make naff all difference as they are probably a long way from det anyway, its mainly the mid rpm high throttle position ones you need to worry about.

 

[Stu_182]

Thanks for the reply mate just always wondered as I sometimes have to plan journeys via a shell garage instead of any normal one.

 

[Chip-mk1]

One thing to remember is that couple of month old vpower is probably a lower knock resistance than fresh 97.
So most mappers leave at least a couple of degrees safety margin in for vpower just in case the car isnt used for a while!