Where to buy 98Ron or can I use 99

[Dylan1]

thanks for clarifying that Ian!

 

[warren_cox]

There is another dimension to this discussion that sits outside the world of performance or MPG. The more expensive fuels are 'supposed' to have cleaning additives which stop the coking of the valves, and ensure that as the engine ages there is less carbonation from any unburned fuel deposits. I've always been slightly dubious of the claims made my some of the fuel companies about the benefits of these upmarket fuels, and I think in normally aspirated vehicles you are likely to notice less of a difference between 95RON and 99RON as your NA engines aren't exposed to the kind of heat and boost pressures of say a heavily moddified turbo charged engine. Once the ECU goes through adaptation to accommodate a fuel change in a turbo charged engine you can see over 10bhp and even more torque lb/ft variation between 95RON and 99RON. In a petrol engine this is likely to be significantly lower to the point of undetectable (can you tell a 5bhp difference at 300bhp?!). Good practice measure would be to choose a fuel and STICK WITH IT, as you are not forcing the ECU to constantly adapt to the new knock settings. I'd imagine in the US these cars must be able to run on 91RON, so it won't so much damage the car as hinder it. Why would you feed your pride and joy anything less that the best?? Would you use cheap oil? That said, I wouldn't lose any sleep over any of it as it's percentiles of difference.