Just thought I would share my results.
I did a 400km round trip today. Most of it was highway and my speed was always in the 90-100km/h range. With the occasional foot to the floor to pass excessively slow drivers. When I arrived home my average km/litre on the dash was.......9.8 ltr/100k.
Don't know about you but I thought that was amazing for a V8 4.2 s/c car.
My usual commute is approx. 75k's round trip. So this was a welcome change.
Usually over the normal commute I get 12.2 for the week average. Still not bad. That's about a 60% hgwy and 40% town. Just thought I would share

 

Wow, not bad at all..

 

Yes it´s possible to drive economically even with a supercharged Jag.

My best is 9,20ltrs/100 kms but you have to be careful with the pedal!!

Rgds / Bo

 

9.2 wow, nice. I am often asked what the fuel economy is like on one of these. People expect them to be heavy guzzlers. Whilst you can no way say they are economical. It did surprise me how good they can be on long runs.

 

I'm lucky to get 10MPG driving to the office.. Highway I can get around 20MPG averaging 80MPH. The trick is to stay out of the boost, which is a trick within in it self as its so much fun.