Any issue in mixing premium fuels?

[Slinkie]

Hi all,

I have always used regular petrol from different petrol stations. I now own a stage 1 mountuned focus st and would like to see the effect of a higher ron petrol, I can track mpg etc easily and would like to see if i can feel any difference in performance (I have been advised that due to the tuning a higher ron will help it run better).

Is there any issue with mixing premium fuels? I know some people stick to one brand but I presume this is usually for loyalty points etc.

I always mixed fuels of different brands (usually cheap supermarket petrol) in my old cars but they never had the performance of my ST.

 

[Minstadave]

No problem at all.

 

[PobodY]

The reality is that they probably all came from the same refinery supplying your area; yes there will be different additives, and Shell (for example) will always keep the best cuts for themselves if it's their refinery (e.g. Stanlow).

Higher RON fuel is one of those things that only has an effect if you can use it. In a N/A town car tuned for fuel efficiency there is no need to use it because you'll never get any detonation. - In a forced induction car there's every chance you will, so using the higher rated fuel give you more protection... then you can run more ignition advance and get more power.

 

[MeEsH BaKkA]

Not using higher RON fuel in a FI tuned car is unwise, whilst the car will still pull timing etc... Higher boost and higher inlet temps leave less of a margin for knock.