Dear fellow Jag-entusiasts,

what are your experiences and opinions on the use of these? A friend of mine has a 1998 XJR and swears by Royal Purple MAX octane booster.
My 1996 XJ 4.0 has 175 000 km on the clock. I have already installed the Andy bracket and is very pleased with the effect.

Thank you and kind regards,
Vidar

 

98 octane petrol, better combustion and more economical in consumption.

 

Your engine is tuned for a certain octane. Go lower, and the knock sensors will make the adjustments to the engine. It'll run, just at a lower efficiency. You'll probably notice a reduction to your MPG.

Go higher, and the car will run normal. You will see no benefits. It's like putting the highest rated gas in an old car tuned for the low grade stuff....no difference.

If your friend believes theres a difference, who am I to tell him it's not worth spending money on?!?! I know people who spend money on worse things!