yesterday I drove abt. 600miles (900km). 90% highway. average speed: 90MPH (140) on cruise control most of the time, no significant traffic.

average on the trip was: 20.7 MPG (14l/100km)

one point to be noticed is that the GPS indicated speed when my odometer was showing exactly 140 km/h and 2500 RPM was 133 km/h.

 

I usually get about the same.
The best was a long drive at 70MPH/110KPH where I got 22.7mpg.

You are right about the speed difference between GPS and the speedo. However, I have a Bluetooth OBD connector that works with the Torque app' on my phone. The ECU shows the real speed and is always less than what the speedo shows. It's more in line with the GPS speed when on a level road.
All to do with most speedo's over-reading by up to 10%.

Oddly enough, my new wheel and tyre set up has had the effect of making the speedo more accurate. Still about 2mph fast though.

Les.

 

I get on a very good run ( W12 Speed) around 22 miles per UK gallon thats 22 miles to 8 imperial pints. So 22 miles to 6.6 us pints a US gallon is on another level of economy....I don't understand quite whats going on here. 1 UK pint is 0.56826 ltrs . Is the US pint also smaller than a UK pint as is with the US gallon being smaller than a UK Gallon?
I need to do some googleing

 

''The best was a long drive at 70MPH/110KPH where I got 22.7mpg.''
Les, this must have been boring like hell!! must have been in France with speed cameras everywhere.

I have read that un Russian guy, with a CGT, has been caught at 201 km/h...they seize his car on the spot!!

Sunnyside, you lost me! when you guys are going metric

 

It would appear your gallon is not the same a our gallon and further to add to that your pint is not as large as our pint. US pint is 0.473 ltr our is 0.568 ltr. I'm trying to perceive if your mph of 22+ mph would equate to our average of 18 to 20 mph ?
Frank.

 

No Ulstrup, I had loads of time to get from the Loire to the Eurotunnel so just set the cruise at 70mph. I have the speed cameras for France and the UK on my phone as well so no worries there.

Should I feel sorry for the Ruskie? Not really, have you seen the clips on Youtube of Russian driving. They are completely nuts.

Metric! Never, it's one thing that Brussels haven't forced upon us Brit's, yet.

P.S. If you ever get to use the Eurotunnel, book as a high vehicle. That way you get to go in the coaches with wider lanes. The normal coaches are a bit scary if you value your alloy wheels as much as I do. The staff are quite used to people with nice cars doing this so no worries.

Les.

 

The best I have seen on a trip was 21 mpg/us with my W12. There are times that I get around 12mpg but average 15.5. I do have pipes and a tune so i probably burn a little more than the stock car but the power gains are worth it for me. If I need milage I'll take the wife's Audi A7.