Hello every one.

Since day one I have put high octane petrol into my Superb as I was advised that it was good for the engine...not to enhance performance or economy, necessarily, I'm not particularly interested in that.

So, I'm considering an addition...an 04 plate 34K miler Jaguar XJ Super V8 (4.2 supercharged engine). My question is...would it be sensible to continue to put high octane fuel into that engine, or would it be a waste of money...its 4/5 ppl more expensive than 95 octane and being as the Jag will only do 20MPG it could be rather expensive.

Your thoughts and advice would be most useful.

Many thanks.

Mike.

One of my fav cars ever! If I did low miles I'd be running a supercharged XJ

I doubt running it on Super will have any advantage unless you're stuck with supermarket 95RON. Decent (Shell etc) standard stuff should be fine.

From my previous experience when running an Imprezza, I found that Shell Optimax (the forerunner to V-Power) gave a 10% reduction in fuel consumption and the engine felt more responsive. This better fuel economy certainly made up for the additional cost when I was getting 24 mpg on regular pump fuel.

Bottom line will be that if you buy the car to find out whether fuel with a higher octane gives rise to any increase in economy and performance. Not sure that running the Superb on the higher octane fuel is at all beneficial though.

My 740i runs loads better on Tesco Momentum 99 than any normal 95. Slightly better MPG (22 vs 19) and better responsiveness.

I run my vrs on optimax and it feels to run alot better on it than it does on normal stuff,

I would imagine jag will be same