I'm using the figures that the car tells me, and being uk based I imagine that'd be imperial figures. I was thinking of having my vehicle converted to run on LPG gas, as well as petrol and will follow that idea up if fuel prices continue to rise as they do.

 

I think we would be better off quoting average speed from the computer as well as mpg. Currently, I get only 14.8 mpg but my average speed is only 18 mph as well. A lot of town work recently.

 

16.8mpg (US) / 28 mph average / '00 XJR / A/C off / Shell Techron 91 Octane / Light right foot

 

If I'm honest, I find that driving with AC on or off makes no difference to the MPG. I never have it off, I prefer it to normal fan and steamed up glass. However, strangely enough I find it does better mpg with Sport mode on. I was on the motorway the other day and switched it on to see what happened, and it crept up from 28mpg (Sport Off) to 32mpg (Sport on!) Maybe the extra power it releases helped? Strange, but good!

 

Interesting...... I'll do a "controlled experiment" on the next tankful and see if Sport mode makes a difference. Any excuse to put it into Sport mode really..... :-)

 

The 'Sport' mode switch only raises the TCM controlled transmission shift points through the gearing by 300-400 rpm providing a little more engine power without downshifting. It has no affect on final gear ratio so I cannot see what affect it would have on fuel mileage.

 

I am getting horrible gas mileage, roughly 280-300 miles / tankI knew it would go down when I went from 265/60r17s on my Avy wheels to 285/50r20s on my Centerlines and it wasnt too bad when I first swapped them but it has gotten worse since MayI drive alot of freeway miles and have driving with the windows up while on the highway but havent noticed any difference other than taking my foot out of the gas what can I do maintenance wise to get better mileage???the fuel filter will be replaced when my tank runs down, probably Friday or Saturday before work

 

Well that sure makes me feel a lot better, now that you're getting close to what I get!! I now realize that some of the other members are quoting British MPG (5 litres as opposed to 4 per gallon). Some of the members are getting 32 MPG....I don't even get that on my 1.8 litre C230 Mercedes.........!!!

Alan.

 

My Dad's 2003 MG ZT CDTi 135+ is the most surprising MPG wise. Powered by a 2.0 4 Cyl Diesel from BMW, it can do 35mpg round town, 48mpg on a combined run, and 63mpg on the motorways! That is amazing for a car the same size as a BMW 5 Series! Being the MG version, its got a sporty look with mesh grills, lower stiffer suspension and 18 Inch Alloys.
I borrowed it to go to Sheffield when my XJ was in for rear brakes, and got a shock. Being in "Jag Mode" I put £40 of Diesel in it, but it only used about £15 of that! Dad was pleased because he got fuel for free! Ha Ha! Still I love XJ and wouldn't swap it for anything right now.

 

Stu do you have a picture of that MG? I've never seen one in the US.

Alan.

 

I'll put pics up soon. They never released them in USA, though there were plans to before MG Rover went bust. The ZT is based on the Rover 75 Saloon, though had design enhancements and chassis upgrades from the same man who designed the Mclaren F1. They came with a Turbo Charged 1.8 petrol, 2.5 V6 Petrol, 2.0 Diesel and a 4.6 V8 Petrol engine from the Ford Mustang. They made them in both saloon and estate (Station Wagon) bodies. A tuned MG ZT-T estate actually broke a world record as the World's Fastest (non-production) Estate car with a top speed of 225.609 mph. It achieved this at 55th annual Bonneville Speed Week, at the Salt Flats in Utah. This one was heavily modified, but still retained a factory look.

Sadly though MG Rover went bust after a sour deal with a chinese car company. I'll add a picture of my Dad's "Batmobile" soon. Hope the info was helpful. S.

 

I assume it's British Racing Green with a Union Jack on the roof ?

 

No its metallic gun metal grey, with custom interior. All our family vehicles feature a James Hunt Hesketh Racing Bear in the corner of the windscreen though. Racing for Britain!