40.9 mpg is the best i could achieve

[Bashy]

Originally Posted by Clan

what were your tyre pressures for interest? 38 makes a big difference to 28 psi !

Ive always put in 34 PSi

I suppose driving through Norwich didnt help, but it was pretty much a straight run through...

As for my best results with CC on, I have tested this idea, there is far too much fluctuation with the right foot, you can test this yourself, stick it in "Instantaneous" mode and you will see that trying to keep the pedal at the sweet spot where its producing the maximum mpg return is near on impossible, even more so when there is even the slightest of inclines, the right foot is too sensitive and over compensates (heavy foot), with the CC on, the computer keeps it spot on, just enough fuel all the time.

I have played with the above a lot and still do and always return the same results, lower speeds is quite interesting too, same results mind, but in that respect, switching the box to manual is far better for better mpg as you can change up much sooner than the auto does, about 33'ish lets you change into 6 as opposed to about 3rd or 4th in auto mode, thats on a flat road though.

Before this V70, i would have said that CC will always use more fuel and swore by it, its always been the case for my with my other cars...

[stuart bowes]

my CC is a bit strange, I do have to keep an eye on it a bit, I dont know how normal this is..

say for example I'm doing 30 at about 1500rpm, I can press the CC button and it will stay there.

OR i can ease off the pedal to about 12-1300rpm and press the button and it stays there as well

(numbers probably not exact but makes the point)

sometimes depending on incline it will creep back up to 1500 and sometimes it will just stay there. so I do have to be aware of what revs I'm at before I press the button. The same is true at all the different road speeds I've tried so far.. while I'm using it I periodically switch it off and let the revs drop a bit, then put i back on again to see if I can settle it a bit lower down

If you're not paying attention you can use it to waste petrol, if you're a bit more savvy with it it, you can be economical

also, it feels weird when the CC has locked my revs at 3 or 4000 so when you press the throttle nothing happens at first until you get to that point. like oh no the pedal is dead! oh, no there it is

always a bit disconcerting

I've been using 35psi and plan to go for 38psi on longer runs / loaded up with camping gear. I went with reinforced tyres so it can take a bit more probably

[Bashy]

It's not the revs it locks in, it's the mpg, hence your revs fluctuate

[stuart bowes]

no I get it's not 'locking the revs' as such, that was just a figure of speech, it tries to maintain speed and the throttle is a fly-by-wire affair (which Im not a huge fan of tbh)

but no the point is, sometimes I can achieve a better revs to speed ratio than the CC calculates, which is proven by the fact you tap the brake, let the revs drop a bit, use the pedals to get the revs you want, and 'lock that in' (so to speak) with the CC button. and it stays there, until a hill or maybe a head wind, or whatever

I'm only talking small amounts obviously, but over 100 miles that would make a big difference

also, mine is petrol so my mpg figures are even more of a concern lol if I drove a tractor *ahem* sorry I mean diesel I wouldn't be so worried

[Bashy]

Originally Posted by stuart bowes

no I get it's not 'locking the revs' as such, that was just a figure of speech, it tries to maintain speed and the throttle is a fly-by-wire affair (which Im not a huge fan of tbh)

but no the point is, sometimes I can achieve a better revs to speed ratio than the CC calculates, which is proven by the fact you tap the brake, let the revs drop a bit, use the pedals to get the revs you want, and 'lock that in' (so to speak) with the CC button. and it stays there, until a hill or maybe a head wind, or whatever

The only time I notice what you're seeing is when there's an incline or decline, also if its in manual or auto.

That's why I like to use cc with manual at lower speeds, that way you can keep the revs lower, in auto, the box's takes longer to change gear, thus ya higher revs and I turn more fuel...

[stuart bowes]

well yeah true I dont have that option mine is just the basic autobox and I change gear with my right foot

but this does occur at all speeds and I constantly 'trim' the CC as I go. or at least, keep an eye on my revs every couple of mins or so

[Bashy]

Originally Posted by stuart bowes

well yeah true I dont have that option mine is just the basic autobox and I change gear with my right foot

Oh, bummer, you don't have the geartronic?
I see your issues now..

[stuart bowes]

blame the missus who only got a girl-o-matic license :/

im definitely more of a manual guy but this one is pretty smooth and comfy and stress-free tbh (as long as I just forget about the fuel)

in fairness I bought a volvo fully in the knowledge that they drink and it's not a major drama, it's just lets try and keep it to a minimum eh

[Bashy]

Originally Posted by stuart bowes

blame the missus who only got a girl-o-matic license :/

im definitely more of a manual guy but this one is pretty smooth and comfy and stress-free tbh (as long as I just forget about the fuel)

in fairness I bought a volvo fully in the knowledge that they drink and it's not a major drama, it's just lets try and keep it to a minimum eh

Ha ha, yeah, I hear ya

[Rolvo]

Yep, I guess GeorgeandKira's right, we diesel dogs do have all the fun! My fun is a 2002 V70 D5, 240K on the clock, auto box, climate control left on all the time. My wife travels badly, high speed especially bad, so even on my own I've now got a bit of a habit, on a motorway run, of sitting to the left with the lorries, cruise control somewhere between 56 and 60mph, and watching the average mpg figure get better and better.
I've had it well into the 60s mpg many times. And yes, the readout on mine is accurate - I've cross-checked more than once by doing a fuel-vs-mileage check between full tanks.
Here's an honest tale (and petrol cats will hate me for this), I once did a 90-mile early-morning run, full tank to start, all but the first few miles on a motorway at 50mph and a few gentle hills. When I stopped, the readout said 84mpg average and miles-to-empty 1,255. Unbelievable but true!
Previously had a 1998 V70 2.5 petrol, struggled to get 40 mpg, even with all the boring driving style as above, in fact I don't think I ever did manage it.