Fuel efficiency on motorways

fluffysox

Hi

We're looking to buy a second hand car for OH to commute to work each day. He does approx 65 miles a day- almost entirely motorway at 70 mph.
Anyway we have different ideas about which car would be the most efficient fuel wise.
We're agreed that a diesel is a good idea. But is it better to have a bigger engined car e.g. 2.0 possibly with 6 gears so the car is driving in lower revs or a smaller, lighter car with a smaller engine e.g. 1.4???

Would be grateful for your views:p

fluffysox

davidjwest

Diesel with 6 speed would be good, my Mondeo 2.0 TDCi is pretty good returning around 60 MPG on the motorway but he'll save quite a bit of fuel if he can stick to 60mph. Assuming it's 30 miles each way it will add less than 5 minutes to the total journey time.

When I first got my Mondeo I did a run at 80mph and returned around 45MPG and then tried at 60mpg returning over 60MPG so for the extra 10 minutes it takes me it saves about £3 a day.

I earn £16 an hour or so and on that basis £3 for 10 minutes is worthwhile.

daveyjp

My A2 did mid 50s mpg (1.4 TDi 3 cylinder), but to achieve the best mpg you need to be driving at 60 rather than 70, but my 6 speed diesel doesn't get into 6th until about 65mph, below this it labours and needs 5th.

vikingaero

Depends on the gearing of each of the cars. A smaller engined car may perform better if it is geared correctly for your commute. A larger engined car may not be ideal. In my Mazda diesel 50mph is too low for 6th gear and I need to remain in 5th or speed up.

forgotmyname

6th gear at 60mph may actually get worse consumption than using 5th gear.

All depends on the road and how much power is available at those revs.

Rossy.

I tend to stick to 65mph on the motorway in 6th in my Laguna 1.9dci

It returns around 57-60mpg

Hammyman

fluffysox wrote: »

We're agreed that a diesel is a good idea. But is it better to have a bigger engined car e.g. 2.0 possibly with 6 gears so the car is driving in lower revs or a smaller, lighter car with a smaller engine e.g. 1.4???

Would be grateful for your views:p

fluffysox

OK...
A friend of the family and we did a trip to the Loire region of France from East Yorkshire - about 2000 miles all in during that week with all the running around. The end result was that with a car full of kids and wife and associated gear, my 2L Mondeo TDCi managed 55 MPG. The other car was a Renault Clio 1.5D with two adults and their luggage. They averaged 73MPG.

However I had the more comfortable journey and I would quite happily take a 20% difference in economy for that. .

iceblue24

my mondeo 2.0 tdci gets around 60mpg on the motorway in 6th gear at 65-70mph with cruise control. below 60mph shift down into 5th and also for overtaking and going up hills

alexlyne

if it's a designated second car then if he can live with a small car it'll be much cheaper to tax and service each year. Smaller tyres are also cheaper (ok may not last as long). A small diesel (Clios as mentioned above are always supposed to be good for mpg) will return much better mpg.

Hintza

65 miles a day is quite a lot of driving and for me comfort would outweigh fuel consumption and on that basis I would be looking for a bigger car.

vikingaero

Hintza wrote: »

65 miles a day is quite a lot of driving and for me comfort would outweigh fuel consumption and on that basis I would be looking for a bigger car.

A 65 mile commute along a flattish smooth motorway isn't that long distance. At 70 mph with the slower parts at start and finish = a 1 hour commute. Plenty of people I know have 2-3 hour commutes by car.