proof that 99 ron massively outperforms 95 Ron

[pearce_jj]

I fail to understand how using 95 RON fuel - which is approved, and has to be - could in any way cause any kind of damage whatsoever. The piezo knock sensor simply retards the ignition under load to avoid knock, which is the whole point.

[Ad Lav]

You miss the point we're making - the 98ron run cars will run better and get better mpg. That's all! They will, as you say run perfectly well on 95ron but if they say it'll run better on 98ron you be stupid not to use it

[jonny boy]

Yeah, as I've mentioned, my mapped car is more economical by some 5mpg.

[Moist Von Lipwig]

Why is it I get the feeling that the arguments for and against the different fuels is going to go on and on, no matter what 'proof' is provided.

[pearce_jj]

You miss the point we're making - the 98ron run cars will run better and get better mpg. That's all! They will, as you say run perfectly well on 95ron but if they say it'll run better on 98ron you be stupid not to use it

Not sure if that was in reply to me, but FWIW I was commenting on Jordo's comment above "If I went to buy any performance car second hand, be it a VRS or a Porsche, if the owner told me he always used 95RON I would not touch it!".

Having read what I think is enough to make an informed opinion, it seems to me that 98 RON is indeed the 'correct' fuel to use for basically any forced induction motor if you're worried about performance - 95 RON will probably reduce engine power (compared to that claimed) and if driven hard(ish) will probably return lower MPG too. So basically I'm agreeing with you

Many moons ago I had an Octavia 1.8T which always felt slower than claimed, I now wonder how much difference 98 RON would have made.

[MartynVRS]

At last there seems to be consensus!