All of the petrol variants of our cars are tuned in the UK to use 95 Ron fuel, there is absolutely no benefit whatsoever in using 98 Ron fuel, the car will not run better, you will not become irresistible to the opposite sex, and your car will not do an extra 50 MPG.
Higher octane fuel is less prone to pinking............so if you need to fuel your P6 V8 with five star, then you can still buy "real" petrol from BMH.
Back to the here and now, other markets are tuned for lower Octane fuels, Australia for instance use 92 RON fuel, and their "premium" fuel is actually 95 RON
With the low mileage cars, I leave only a small amount of fuel in there, and when pressed into action, fill as required as modern fuels tend to go stale when standing,
due to the ethanol content as required by the EU,being both hygroscopic and having a tendency to evaporate off, this of course applies to both 95 and 98 RON fuel.
Another fact, the higher the octane rating, the higher the temperature of the spark required to ignite the mixture, this is why the ignition system of cars running LPG need to be in top condition.......incidentally LPG is circa 110 RON, however the calorific value is lower than petrol, so you have to burn 20% more to achieve the same output.
It's not all about octane either, a little light reading
HERE
Brian
