Just back from XJC 4th birthday display on the weekend in my XJRs, 6 litre 4L80E conversion, 2 adults plus 2 grandsons, at 540 kl took 56 litres. That is about half the journey and l have not calculated the second half yet but fuel gauge indicates a repeat of above figures.
Just a touch over 10 litres per 100 kl, that makes it the most economical vehicle l own. Pic of dash is pretty typical of entire trip.

 

Sweet.

Yep, the V12 is economical, and with that conversion, so sensible by the way, you have really nailed it.

That volt meter looks a tad low????. but maybe that is the barrel gauge syndrome.

 

If I could make close to 10L/100km I would be happy.

 

Maybe by the gauge Grant but hasn't shown any signs of trouble. Car is kept on a tender while stored and the dash shot was well into the trip with nothing on so battery would have been well and truly topped up.
Will certainly check it at first sign of trouble.

 

You have a good tuned six liters. My six eat often more than your. It is 9-10 l where average speed is 90 km.h, 10- 11 100km,h 14 and more when 140kmh. This is actually when highway only. City traffic is 23L 100 km. My style is not smoothly.

 

I am running original 5.3 manifolds and injectors, slightly raised fuel pressure and super enhanced ECU.
This trip was pretty much all highway.
City driving thrown in drops it to around 13 litres per 100k.

 

Man that is great mileage...
I was happy when I got 13.1 MPG in the city... (17.95531 l /100klm)


but that was after she had warmed up and I topped the tank off and reset the computer.... did not last long as I drive to work in warm up mode... 3/4 the way...


hwy I get 18mpg about 13 liter /100km


so doing the 4speed OD conversion leaving the 2.88 ratio in would accomplish this?


of course you have to get the 6.0v12 that goes w that transmission..


things to do in the future when things are available .... :-)

 

Thats good economy.

Gives me hope for when I install my 4L60e.

I get about 14l/100km ATM with 3.58 and the 3 speed at 100km/h spinning at 3000rpm.