Fuel quality requirements

Hi All,
I’ve always used the highest octane fuel available in my '97 XK8, 98 octane.
With gas prices on the up ( and up and up) do I need to use the best? In NZ we have 91, 95 and 98 available, all unleaded; I think the 98 may have some ethanol to boost the rating, but I’m not sure about the others. Happy to use the best if necessary, but not needlessly.

My experience driving the 5 Jags I have owned, is that I have not seen any quantifiable difference between regular, mid grade and premium, when used in any of my cars, including my 98 KK8. Although I normally use premium fuel, I have not seen or felt any difference in performance or fuel economy when I’ve used multiple tanks of regular.

The good thing about ‘KS’ (knock sensors) is that they with keep the engine from damaging itself if the fuel quality is lower than required to run without ‘detonation’.

Regular Unleaded will work just fine in most modern cars. (turbo and SC are probably the exception)

Hi Kevin, I regularly run my ‘99 XJR on the 95 from most of the usuals, I steer clear of Gull unless its necessary due to location.

Ill say i tried running low grade in my 93 xjs and my 97 xk8 for a couple of weeks. I did actually see a small gain in avg mpg in the xk8 with the low grade for whatever reason, however, i actually started hearing some pinging on heavy acceleration, more in the xjs than the xk8. I did hear it in the xk8 though too. I am switching back to high test, but it definitely hurts as i just put $90 in my xjs to fill it yesterday :face_with_symbols_over_mouth::face_with_symbols_over_mouth::face_with_symbols_over_mouth: