[Sephanite]

Actually, the lower octane petrols give you more km's per tank. I personally fill on 98 RON as i have a tune in the car and can take advantage of the greater octane but our Lexus has switched from 98 RON to 91 RON.

[David328M-Sport]

Originally Posted by Sephanite

Actually, the lower octane petrols give you more km's per tank.

Not our experience with 98 v 95 (never lower) in my wife's Merc.
Initially we used 95 (or whatever it was back on '03) and then changed to 98 as an experiment. Well it worked.

Been using 98 for years as it gave her car more kms per tank compared to 95.
Sure it costs more than 95, but it's also supposedly a better fuel with cleaning additives etc.

However, the 98 v 95 experiment in my son's '98 Saab 9-3 didn't work in favour of 98. So it's 95 for his car.

[jctg]

Originally Posted by Sephanite

Actually, the lower octane petrols give you more km's per tank. I personally fill on 98 RON as i have a tune in the car and can take advantage of the greater octane but our Lexus has switched from 98 RON to 91 RON.

I think that depends very much on how the car is tune from factory. I find the 98 gives me more kms per tank. But most cars on the road are tuned for 91 and 95 so it wouldn't surprise me if 98 don't yield better economy. Ours I expect is tuned for 95 and 98.