Fuel Economy with the Cooper SD

[Billwill]

I've had my brand new Cooper SD for a couple of weeks and the first fuel economy figures I've got, for typical mixed urban and extra urban driving is 50.5mpg - which isn't near the BMW quoted 65mpg.

I'm sure the engine will loosen off and improve.

Anyone got numbers to share for your mini?

Cheers

[Billwill]

2nd tank numbers, with a bit of motorway driving resulted a little more respectable 55mpg. Still well away from BMW's figures, but way better than my last car.

[dirchy]

I expect it will creep up as the engine loosens up a bit. How do you find the SD? I'd like to see how much effect a remap has when they are available.
I was seriously tempted by one, but ended up going for a slightly older S for now. SDs a possibility for a year or twos time.

[Billwill]

It's great. The power delivery is there for overtaking at 40 to 60mph. It sticks to the road very well - it'll be far better on winter roads that all of my previous cars and the gearbox is great.

The only negative is the start/stop feature - it works when it likes, but when it's not working, it usually doesn't work for the whole journey.

[barleydave]

Quote: Originally Posted by Billwill (original)

I've had my brand new Cooper SD for a couple of weeks and the first fuel economy figures I've got, for typical mixed urban and extra urban driving is 50.5mpg - which isn't near the BMW quoted 65mpg.

I'm sure the engine will loosen off and improve.

Anyone got numbers to share for your mini?

Cheers

I had the same point of view with my Cooper D. BMW quote 75MPG, and I actually get 64MPG - still an amazing consumption with virtually nothing else in its class coming near.

The official figures are produced on a rolling road, so it is very unlikely that you will ever get exactly what they quote as they don't have cars pulling out on you, a desire to take someone on the motorway etc.

David

[ed_vh]

I just purchased a 8 month old cooper SD that has done 7k miles. First few trips were also round the 50mpg mark. Today I decided to drive home as efficiently as possible and managed to average 64.8mpg! This was a mix of duel carriageway at 70 and winding A/B rounds at 45-60 over 15 miles. The key seamed to be accelerating at a snails pace! Very pleased with that but not sure how long I will be able to be so ginger with my right foot!

It makes a change to my last car. A nissan 350z which averaged 24mpg and cost £90 a tank. Just filled the mini for £43!

Loving it!

[ALD0]

I would think anything over 54mpg in modern day driving is good

Doubtful you'll ever get the manufacturers clawed consumption!

[Angib]

Quote: Originally Posted by ed_vh (original)

The key seamed to be accelerating at a snails pace!

Why do you think that? Because you were looking at the fuel consumption readout?

It's a common belief that slow acceleration is fuel-efficient but it isn't - it just spreads the pain over a longer period, so it doesn't look as bad. With a petrol engine, slow acceleration is actually worse than brisk (not balls-out) acceleration, but with a diesel the gap is much less.

The single worst thing you can do for fuel economy is the thing that gives the best apparent fuel economy - using the brakes. That is just throwing energy away that you have paid highly to get.

Fuel economy readouts serve a useful purpose when used over a long distance, but short-term or instantaneous readouts are so misleading that using them is nearly always pointless.

[happy67]

i've had my SD Clubman for 3 months now, its just starting to loosen up at 4k miles from new. getting about 55-60 mpg, much better than last mini s petrol, although the grunt through the gears is different.

[ed_vh]

Quote: Originally Posted by Angib (original)

Why do you think that? Because you were looking at the fuel consumption readout?
......
Fuel economy readouts serve a useful purpose when used over a long distance, but short-term or instantaneous readouts are so misleading that using them is nearly always pointless.

I am intrigued by your doubt in fuel economy readouts. I am not familiar with the mini system but on other car designs I am familiar with the fuel readout instant is calculated from injector pump pulses and current speed. On a modern car an injector pump is extreamly accurate. The average mpg is an integration (average over time) of this and should also be pretty accurate. I admit though it is pretty difficult to read the instant as it shifts all over the place with throttle position, revs and speed!

My comment was based on watching the moving average and agree any use of the brake is simply throwing the energy away!

I have not tried different rates of acceleration. Thats a good idea - I will see how it goes with a 'normal' level of acceleration.

[Angib]

I'm not saying that the readouts are inaccurate (though to a minor extent, they all seem to lie), but misleading. They encourage drivers to do whatever seems to make the readout not drop right now, when that may not be the most economical way of driving.

For example, two alternative strategies for accelerating from 30mph to 60mph may be:
- 10 seconds full-throttle at 10mpg and then cruise at 60mpg, or
- 40 seconds part-throttle at 20mpg.

The first of these uses only 75% of the fuel of the second, but the readout will encourage the second.

The readouts work well over a whole journey but provide poor short-term information. And even over whole journey they need to be read with caution - we have a terrible tendency to get the answer we are looking for, by ignoring readings which we don't like.