What fuel with new 5.0 V8 supercharged?

[jagseven]

I have tended to put Shell 99 ron fuel in my XFR since picking it up a couple of months ago.
I was doing this partly becasue it might boost power (hardly in a short suppy anyway) but also because of the cleaning benefits of the more expensive fuels.

But I read something in this months EVO that suggested that the cleaning benefits are lost with a direct injection engine.

Can anyway shed any light on this - am I wasting my money on the higher ron fuel?

[NormanD]

The 4.0/4.2Lt as well as the 5Lt engines are designed to use standard unleaded

Putting 99 in unless you have seriously upgraded your engine is a waste of £££


You have been taken in by the petrol companies advertising

[Triple7]

Tricky one. I use Optimax Diesel, it does produce more power, less smoke and runs smoother and quieter. ;-)

As long as you don't use supermarket fuel, I'd say the extra cash on fancy fuel in a 510bhp car is not worth it.

So give us an overview of your time with the XFR, think I'll be heading that way.......

[chris_w]

I use the regular stuff because it's painful enough filling up every 280 miles as it is. Love the car, and that engine, but hard work bettering 20mpg unless you're on a very steady run.

[The Leaper]

I don't have an XFR (if only) but I do have an S-Type 4.2 V8. I was seduced by the ads for 99 and used it for a while. No discernable change whatsoever unless, strangely, I used the Esso variety which seemed to give something to the performance. 95 seems OK so I'm pocketing the difference.

R.

[steve-p]

I'm using 95 RON in my XKR for the simple reason that I probably won't notice any minor reduction in power - who is going to miss 4% or whatever of 500+ bhp - but I would notice the extra cost at 250 miles on a tank.

[jagseven]

But what about the supposed cleaning benefits or does branded 95 ron fuel have these additives as well?
I've read a few reports over the years that suggest that higher ron fuel does boost power, especially on turbo engines (so maybe supercharged as well?) but I have to confess to not noticing any obvious difference when I had my 4.2 XJR

It was because the 5.0 V8 is direct injection that got me thinking if things might be different....

Triple 7 - to answer your question, the XFR has been brilliant. I've only done about 2k miles and the weather has recently stopped me exploring the handling (I've tried winter mode once but since then the car has been tucked up in the garage) but it's by far the best Jag I've owned. It does the jag thing of luxury just as well as a regular jag but also seems to come alive when pressing on. It feels extremely well balanced - everything from the weight of the controls to the way if flows from bend to bend. And then there is the V8 which still feels adbsurdly powerful. The paddles allow you to really drive the car when you're in the mood - dropping a couple of gears is so easy on the motorway, say - and then you can fall back into cruise mode. The fact it is a practical saloon is a bonus.

My only real criticism is the sat nav touch screen that can be slow to respond and feels slightly dated/low spec but the interior is first class (love the sports seats) and they have clearly spent the development time and money in all the right places i.e. making the car a joy to drive.

Check out this month's Performance Car mag - it is named Performance Car of the Year and beats such cars as the Nissan GTR, Cayman S, Audi R8 V10 and Lotus Evora for being such a great all rounder.

(Just thought - why is it that the XFR seems to get all the publciity and not the XKR? Would love an XKR but need to space for kids/luggage so perhaps it's the bonus of practicality that is the key = great all rounder)

[chris_w]

jagseven said:

Triple 7 - to answer your question, the XFR has been brilliant. I've only done about 2k miles and the weather has recently stopped me exploring the handling (I've tried winter mode once but since then the car has been tucked up in the garage) but it's by far the best Jag I've owned. It does the jag thing of luxury just as well as a regular jag but also seems to come alive when pressing on. It feels extremely well balanced - everything from the weight of the controls to the way if flows from bend to bend. And then there is the V8 which still feels adbsurdly powerful. The paddles allow you to really drive the car when you're in the mood - dropping a couple of gears is so easy on the motorway, say - and then you can fall back into cruise mode. The fact it is a practical saloon is a bonus.

My only real criticism is the sat nav touch screen that can be slow to respond and feels slightly dated/low spec but the interior is first class (love the sports seats) and they have clearly spent the development time and money in all the right places i.e. making the car a joy to drive.

Check out this month's Performance Car mag - it is named Performance Car of the Year and beats such cars as the Nissan GTR, Cayman S, Audi R8 V10 and Lotus Evora for being such a great all rounder.

(Just thought - why is it that the XFR seems to get all the publciity and not the XKR? Would love an XKR but need to space for kids/luggage so perhaps it's the bonus of practicality that is the key = great all rounder)

Thanks for your thoughts on the XFR, funnily enough they exactly mirror my thoughts on our XKR (minus the practicality of course!). Even down to the criticism of the sat nav (why don't manaufacturers just throw a few quid to Tom Tom and use their software???).

On the practicality note, the XKR does fare particularly badly. Cabin is fine up front but rear seats are useless for all but our dog and boot is real disappointment (though we have the convertible which I suspect doesn't help). And it's a BIG car too, so no excuses, our 911 is far more practical.

I'd love an XFR as our 'sensible' car but for the fuel economy.

Edited by chris_w on Thursday 7th January 13:20

[Triple7]

Thanks for the review.

Guess when the XE roadster arrives, we'll all get what we want..........