It can be done

[V8RS6]

Was a very boring journey from London to Edinburgh in my C7.... but only got 18mpg on the way back!

[wildbore]

I would really like to hear more about how you got that figure. I had a 200-mile motorway run recently and took it easy all the way (too much traffic to do otherwise). I got 26.5 average. I noted that 4-cylinder mode would only engage intermittently and would often drop out only seconds after engaging for no apparent reason - it wouldn't then re-engage for several minutes.
I know it isn't the purpose of these cars but I still would like to see better mpg on long motorway journeys. Any tips to share?
thanks

[W8PMC]

Is that actually the average over the whole journey or a snapshot of a shorter period?

It's a doable figure if sitting at 65-70 for an entire journey but even upping that to 75-80 & you'll be back down to 25-26mpg. A couple of blats & 23-25 would be a norm over that kind of distance.

[V8RS6]

OK, so I cheated a tiny bit.........I took the pic after a steady 70'ish run over 2 hours on the A1. Everything was in comfort mode (Sports exhaust setting kills the mpg). I was using Shell Optimax, which I've found can make up to 5mpg difference, no cruise control so was able to coast sometimes. Not much traffic either so little braking. Actual average for the whole journey including the town traffic was around 26mpg.
I just love this car, not only for when I'm driving in fun mode but also for when I just want a smooth relaxing drive.....its the closest I've ever been to the high quality drive my XFR gave me.
This is my second C7 and as with my first one I did find it took 5,000 plus miles for the engine to fully loosen up. The auto stop-go function for example, on both cars would not work regularly until 3,000 + miles and I've found that tyres can affect the performance as well.... the super sticky Pirellis on my first car refused to yield more than 27mpg however frugally I drove the car. The Continentals on car number 2 are less noisy and also give me extra mpg.
But you're right, economy is not what this car is about and I found that the Pirelli's certainly had the edge where grip at high speed was concerned.

[wildbore]

Thanks for the info.

I am on Continentals - more grip than I will ever need and I am constantly amazed at how whisper quiet this car is.

I will turn off the Sports Exhaust for long journeys and see what happens. Also, in fairness, when I did my long trip (ACC set to 75 but I am aware that ACC isn't a particularly economical way of driving), there was only 500 miles on the clock. There is only 1000 even now.

[Lewy]

I managed a good MPG on a run from London to Teesside, plenty of variation, from cruise control in the 50mph sections and some sporty blasts...

27.5mpg

[Lewy]

[wildbore]

Comparing the two photos on this thread it seems that the key difference between Lewy's car and that of V8RS6 is the driver's choice of radio station.
@Lewy: if you want better mpg you need to tune to a more mellow sound, Raio 1 is too edgy for smooth driving.
@V8RS6: you might hit 34mpg if you retune to Magic.

[RSphantom]

You were nearly right about the radio station but that's not the main reason.

As we all know its all about weight and its clear to see that V8RS6 has emptied his washer bottle and Lewy has not. I never knew the washer bottle carried so much weight

[danilobandeira]

very nice guys... here in brazil our gasoline has 25% of alcohol and my average in city is 23.80l/100km - 4.2 km/l - 8.96 mpg and road is about 13.69 l/100km - 7.3 km/l - 15.6 mpg

[wildbore]

very nice guys... here in brazil our gasoline has 25% of alcohol and my average in city is 23.80l/100km - 4.2 km/l - 8.96 mpg and road is about 13.69 l/100km - 7.3 km/l - 15.6 mpg

I think you are quoting US mpg there - your range (converted to imperial) is 11.9mpg > 20.6mpg - about what we get under normal driving, I think, so the alcohol content doesn't seem to affect consumption too much.

[Lewy]

@Wildbore, I was forced to change to Radio One after the DAB Radio dropped XFM ;(

@RSphantom, yep, my washers were full!

Brilliant theories lads

[V8RS6]

Word of warning here: Don't select the CD drive when attempting to get high mpg, you'll be amazed at how much energy it uses when making the disk turn....best I've ever achieved listening to a CD is 27.mpg.

[Performance]

OK, so I cheated a tiny bit.........I took the pic after a steady 70'ish run over 2 hours on the A1. Everything was in comfort mode (Sports exhaust setting kills the mpg). I was using Shell Optimax, which I've found can make up to 5mpg difference, no cruise control so was able to coast sometimes. Not much traffic either so little braking. Actual average for the whole journey including the town traffic was around 26mpg.
I just love this car, not only for when I'm driving in fun mode but also for when I just want a smooth relaxing drive.....its the closest I've ever been to the high quality drive my XFR gave me.
This is my second C7 and as with my first one I did find it took 5,000 plus miles for the engine to fully loosen up. The auto stop-go function for example, on both cars would not work regularly until 3,000 + miles and I've found that tyres can affect the performance as well.... the super sticky Pirellis on my first car refused to yield more than 27mpg however frugally I drove the car. The Continentals on car number 2 are less noisy and also give me extra mpg.
But you're right, economy is not what this car is about and I found that the Pirelli's certainly had the edge where grip at high speed was concerned.

My M6 GC CP does 24/6 MPG with booting, as soon as the road clears foot down, and we never travel @ 70MPH more like 85/90.
Why the poor economy on these cars? as they are supposed to have 4 cylinder de-activation.

[W8PMC]

OK, so I cheated a tiny bit.........I took the pic after a steady 70'ish run over 2 hours on the A1. Everything was in comfort mode (Sports exhaust setting kills the mpg). I was using Shell Optimax, which I've found can make up to 5mpg difference, no cruise control so was able to coast sometimes. Not much traffic either so little braking. Actual average for the whole journey including the town traffic was around 26mpg.
I just love this car, not only for when I'm driving in fun mode but also for when I just want a smooth relaxing drive.....its the closest I've ever been to the high quality drive my XFR gave me.
This is my second C7 and as with my first one I did find it took 5,000 plus miles for the engine to fully loosen up. The auto stop-go function for example, on both cars would not work regularly until 3,000 + miles and I've found that tyres can affect the performance as well.... the super sticky Pirellis on my first car refused to yield more than 27mpg however frugally I drove the car. The Continentals on car number 2 are less noisy and also give me extra mpg.
But you're right, economy is not what this car is about and I found that the Pirelli's certainly had the edge where grip at high speed was concerned.

My M6 GC CP does 24/6 MPG with booting, as soon as the road clears foot down, and we never travel @ 70MPH more like 85/90.
Why the poor economy on these cars? as they are supposed to have 4 cylinder de-activation.

I'm getting about the same in my M5, but 80% of my driving is Motorway sat at 80mph (when traffic allows) so that pushes my average up a little. Have seen over 30 but as pointed out to the O/P, it was somewhat staged & isn't possible 99% of the time. Mid 20's for a powerful V8 i can live with.