A little PH experiment I would like your help with

[blindswelledrat]

Bill said:

It's a big car with a small engine being made to accelerate at speeds the aerodynamics affect. I'm not surprised tbh, but it'd be interesting* to see how they compare at a steady 70mph.


* Not for you, obviously.

I do find it interesting as I would quite like the holy grail of economy for my specific driving.
Ill do the specific test next time but I think I know the answer.
I reckon at a steady 70 the SAAB may even take it due to the amount of fuel needed for the Peugeot to maintain the speed going uphill on the motorway. Might be wrong- we will see.
What is apparent is that (as someone further up said) it is impossible to maintain a steady speed on a relatively busy motorway for any length of time and that is what kills the Peugeot economy. Sitting at 75 a lorry will overtake and then the 65 mph car in the middle lane will go into your lane. Then the effort of slowing down and then accelerating to 75-80 again afterwards prevents any kind of consistent economical speed.

[thatdude]

My wifes 120d auto (2005, apparently non-DPF which I discovered recently and I am overjoyed) apparently gets a claimed 51 extra-urban, but we see 43, which is in line with mixed.

Urban is about 34, she gets abhout 31. not bad.

[blindswelledrat]

thatdude said:

My wifes 120d auto (2005, apparently non-DPF which I discovered recently and I am overjoyed) apparently gets a claimed 51 extra-urban, but we see 43, which is in line with mixed.

Urban is about 34, she gets abhout 31. not bad.

I think that sound pretty crap to be honest.
A small car with a small diesel engine and you are getting mid to late thirties on average?

[Bill]

blindswelledrat said:

I do find it interesting as I would quite like the holy grail of economy for my specific driving.
Ill do the specific test next time but I think I know the answer.
I reckon at a steady 70 the SAAB may even take it due to the amount of fuel needed for the Peugeot to maintain the speed going uphill on the motorway. Might be wrong- we will see.
What is apparent is that (as someone further up said) it is impossible to maintain a steady speed on a relatively busy motorway for any length of time and that is what kills the Peugeot economy. Sitting at 75 a lorry will overtake and then the 65 mph car in the middle lane will go into your lane. Then the effort of slowing down and then accelerating to 75-80 again afterwards prevents any kind of consistent economical speed.

I have no idea of the answer, I rarely do that kind of journey or pay much attention to economy so there's little point me telling you I get 25+ out of a ten year old Disco or that the one time I checked SWMBO's SMax 2.2 it got 38mpg on a long run in France with a roofbox