How to get better mpg?

[joshwa]

Hi,

I'm going on a big road trip, and wondered if there's a list of things to check or do to improve mpg in a diesel car?

Thanks
Josh

[TeePee]

Drive better.

Tailgate a lorry.

[g8ina]

Keep it at 56mph.

[peterb]

Tyre pressures, cruise control and a light right foot, avoiding hard accelerating and breaking. Keep your speed to around 55mph and your mpg will improve dramatically.

On a motorway that might not be possible, although you can stay in the inside lane and mix it with the trucks, but even keeping below 75 will help, but remember that drag increases pin proportion to the square of speed, so the drag at 80 is four times that at 40. But keeping a constant speed is best, which is where cruise control helps.

I've also found that She'll Vpower gives better economy, although that is negated by the higher cost of the fuel.

[cptwhite_uk]

Drive in the right gear for maximum fuel efficiency - depend on the car and engine size but a good indicator I believe is around 1800-2500 rpm range (higher for smaller engines as they have to work harder
Lower your max speed by 10mph
Leave plenty of space between you and the car in front so you don't have to use the brake constantly - you've basically expending energy to heat up your brake pads / discs.
Anticipate the road ahead (you should be doing this anyway) so you know when to release the accelerator (instead of braking) this goes hand in hand with the point above
Accelerate gently, instead of as fast as possible. Also brake gently if possible, you might be able to conserve momentum if you leave larger gaps
Try to maintain constant speed instead of constantly varying, ideally in whatever gear your using's sweet spot

If it's a long journey and you drive conservatively I would expect you to be able to increase you mpg by 10 at least.

[Xlucine]

For a diesel, it's unlikely to want to rev above 2k in a steady state. I hired a transit recently that would only do 1.5K RPM at 60 in top! Use as high a gear as it'll suffer, within reason.

[kalniel]

All main points already excellently covered, so some additional minor gains:

Keep windows closed, use air con in preference (and normal fans if not needing air con).
Remove junk from the car (but keep anything useful like spare tyre, kits, water etc.)
If you haven't used V-power or redex in a long while, do so for a tank ideally in advance of your trip, making sure to use plenty of revs over time to clean out the engine (aka italian tune up).
Point about conserving energy already made, but when backing off on approach to corners/junctions roundabouts, make sure to stay in gear for as long as possible before depressing clutch, as this will allow the engine to cut off fuel to the engine while it's being turned by the wheels. As soon as you clutch/neutral the engine has to feed (a fairly rich mix) for idling.

[joshwa]

Cool, thanks everyone

It's got cruise control so that'll help.

It's a Ford Mondeo 2.0TDCi (MK3)

[ik9000]

walk?

[g8ina]

On our holiday in France my Picasso 2l diesel gave me 55mpg, as oppsosed to 40 urban. That was about 400 miles single run, only 2 stops, and all on motorways at 70 ish

[Smudger]

I once got 60Mpg out of a Peugeot 406, probably with the same 2.0 diesel engine as yours, g8ina. The combination of m25 dictating speed ('variable speed limit!' = constant 55-60mph) and accidentally putting in V-Power helped, I think...

[Jowsey]

The times when I used to drive a VW Polo bluemotion and I'd achieve a good 65 + mpg on any motorway stint make for pleasant memories.

Sadly, I now drive a Volvo S60 T3 and struggle to get 30 MPG...

[liams]

Tyre pressures definately and even low resistance tyres can change a few mpg change spark plugs over 30k miles if air filter not been changed in a year change it
It isn't for mpg but just to save money fill up early morning when its colder. 10-30 degrees is 2/3% more petrol. or should i say diesel

[kalniel]

My Y reg Astra 1.7dti could just about hit 65mpg on my commute if I took it easy, and our current fiesta 1.6 tdci econetic will happily do 65mpg at motorway speeds all day.

But that's filthy diesel for you I can only get 50mpg average with the A3 1.4tfsi (taking it easy), but it's quite a lot cleaner

[Ttaskmaster]

Škoda Octavia mk1 130PD 1.9TDi - 74 average on motorways!!

[Dashers]

After eeking out the miles in my EV a while ago on a (for an EV) long trip, I found that aerodynamics play a far bigger role than I previously expected.

I found that going over 50mph and you start drastically losing efficiency. My idea was to nip in behind a lorry and get a bit of slip streaming going, but if you're limiting yourself to lorry speeds, you never catch up with one to slot in!

In my more fuel-hungry RS the big impactor has always been acceleration - not even aggressive acceleration, just slowing down for turns or traffic lights are a killer. Stonking it along at questionable speeds doesn't seem to have a major impact - maybe it's a more slippery car than the EV.

But yeah, as above for going on a trip.

- Reduce your weight, swap your space saver for a break down sub and a can of goo.
- Check your tyre pressures are correct
- Find a reputable garage with a Hunter tracking system and check your wheels are all straight (it's amazing how much fuel dragging a tyre sideways will use).
- Check your thermostat is working correctly, as engines need to be maintained at a correct temperature to be efficient