Is there any advantage to using 97 petrol?95

[BigNige]

X308, seems to run just fine on 95 but am wondering if there are any upper range ecu tables that would allow the engine to run nicer (read more power) on 97 or above?

[melhook]

Just for your info, we used to get a lot of xj/xk8's where the customer complained of pinking, mostly it turned out they were usin 95 ron, usually super market stuff.

[Jaguar steve]

I've tried several tanks of BP 97 octane in a row - couldn't feel any difference in performance or refinement and saw no change in fuel consumption either.

Try a sump full of a good quality full synthetic oil - Fusch Supersyn 5W 40 is very cheap at GSF - that's the best value gain in refinement, performance and economy you'll ever get.

[G_T]

Injector cleaning qualities aside I was told it was utterly pointless using higher RON unless your ECU could detect the difference and advance the ignition timing?

I've no idea if this is true, or whether the X308's ECU can do this, but I'd be very interested to find out because I've been running urine grade 95RON for some time now as I'm chuffing skint!

Edited by G_T on Friday 17th April 12:20

[black1]

i put a few tankfulls of tesco 99 rocket fuel in my xk8

in a word waste of money !

[LewisR]

Even my old '86 Saab 900 T16S ran better on high octane fuel as it had an anti-knock sensor and so adjusted ignition timing accordingly. I think that all modern cars with ECUs monitor fuel octane rating and adjust for it. I'm not 100% sure though.

[NormanD]

LewisR said:

Even my old '86 Saab 900 T16S ran better on high octane fuel as it had an anti-knock sensor and so adjusted ignition timing accordingly.
I think that all modern cars with ECUs monitor fuel octane rating and adjust for it. I'm not 100% sure though.

Yes the Jag does have them but they were designed for 95 not to rely on the anti-knock to keep it de-tuned all the time

[ParanoidAndroid]

I've suffered with a bit of pinking in my 4.2 xkr when I floor the throttle. Recently being filling up with Optimax and the pinking seems to have disappeared. So seems to have helped mine.