Ridiculous MPG

Soldato
Joined
18 Oct 2002
Posts
5,367
Location
Dublin, Ireland
When looking for my new car, I knew I had to go for a diesel with the amount of miles I do. For some reason though, I got won over by the not-fantastically-economical e39 530d. Even reading that most people struggled to get 40mpg on a run out of them and averaging around 35mpg, I wasn't put off due to the sheer brilliance of the car.

So with this in mind, I find my rather clean 530d Sport, in manual. Computer was reading 47+mpg all the way home so I thought that was buggered. Until I did the sums.

The lowest I've averaged is 44mpg from a tank, and that would include about 16 cold start 15 mile journeys, all stop start and a few longer journeys.

Today however, I got 56.5mpg (comp indicated, probably more like 52) on a 270 mile round trip today. 50+ MPG in a reasonably heavy car that has 200bhp.... That's just ridiculous. Plans for a remap are out of the window now, if I remapped it and ended up with sub 40mpg I'd be gutted - must be getting old :(

To the other 530d drivers - is my car magical or is everything I read just utter crap?
 
This is completely normal. There is so much rubbish posted about MPG.

What you are acheiving is par for the course with a manual 530d - you'll only ever see it dip below about 33mpg if you spend a whole tankload in town.

Many cars are suprisingly economical if you drive them in a decent fashion - It always amazes me how people seem to think I can pull amazing economy figures out of my car, and assume I must drive everywhere at 50mph.

Errr, nope, it just involves driving beyond the end of your bonnet.

I'm guessing you don't do any of these things:

a) drive at an indicated 80-120mph on the Motorway
b) Drive right up behind the car in front until he moves out the way, at which point you then nail it back up to cruising speed
c) Foot to the floor every time you accelerate
d) Approach traffic lights using throttle when you know you'll have to stop

etc etc.

Simple, non Grandad things like cruising at an indicated 75mph, backing off the throttle instead of braking and anticipating the moves of other road users and traffic lights can do wonders for fuel economy.

It's how I get 38mpg out of a 530i on a Motorway trip.

It's not rocket science.
 
I was gonna say, on a normal run from Home to work (15m, mostly NSL) I only get 37mpg on a Mini ONE...

Fox is right, I would say that was about right..
 
I'm driving the same way I always have - anticipating the road ahead etc. Although I am flooring it a lot less now that I'm paying for fuel. I never averaged more than 25mpg out of any of the jeeps I had though and the factory averages on them were 30+.

So could it be that if I get this remapped I might get even more mpg? The car seems quite laggy/slow to respond under 2k rpm - this normal for them? After that it pulls like a train. Every other diesel I've had pulled from about 1.5k.
 
240bhp here I come so. What does your dad average mpg-wise in his?

Think I need to improve the audio first though - it's rubbish. Have you ever seen one of those "connects2" adapters fitted in place of the cd changer? Gives you an AUX input.
 
Manual or auto?

Mine is significantly higher than that though - I havent seen less than 44mpg (47mpg indicated) and I wouldn't say I was nursing the car, just driving normally. On a trip, I never average anything less than 50mpg indicated...

Your 38mpg is very impressive though, the S-type wont do more than 32mpg, averaging 22mpg....
 
Manual or auto?

Manual.

Mine is significantly higher than that though - I havent seen less than 44mpg (47mpg indicated) and I wouldn't say I was nursing the car, just driving normally. On a trip, I never average anything less than 50mpg indicated...

It wasn't a pure Motorway trip, far from it I think. I've had over 50mpg from it on Motorway trips.

Your 38mpg is very impressive though, the S-type wont do more than 32mpg, averaging 22mpg....

The best I've ever had was 39.2mpg over 381 miles from Devon to Yorkshire at an indicated 75mph, including negotiating the M42 somewhat slower. Although I did have Dunlop SP Sport 2000's on it at the time which are presumably lower rolling resistance than the F1's its got now. Usually though, for pure Motorway, it's 38mpg. I'm off to Hampshire tommorrow, which is mostly A road, and I expect it'll do 33-34mpg for that trip.
 
Can somebody explain how braking makes MPG go down?

Braking itself doesn't, but keeping the fuel flowing then braking later uses more fuel than lifting off earlier and allowing the car to slow down because you can.
 
Because you have invested power in getting the car up to speed and now you are slowing it down just to speed it up again.

Isn't slowing down by not using any throttle/brakes the same though? I mean if you are coming to a stop at traffic lights, you come to a stop whether you brake or just lay off the throttle earlier.

EDIT: Dolph has cleared it up :)
 
Isn't slowing down by not using any throttle/brakes the same though? I mean if you are coming to a stop at traffic lights, you come to a stop whether you brake or just lay off the throttle earlier.

Nope because when you come off the power the car isn't using any fuel, you have the chance of not stopping totally at the lights so no need to speed up as much etc etc.
 
Isn't slowing down by not using any throttle/brakes the same though? I mean if you are coming to a stop at traffic lights, you come to a stop whether you brake or just lay off the throttle earlier.

If you throttle off approaching lights, it will take you longer to reach them than if you drive up to them at normal speed (Using fuel) and then brake. This increases the chance that the lights are changing to green by the time you reach them, avoiding having to come to a complete stop, which stops the need to accelerate from rest, saving more fuel.
 
I just averaged 40.8 mpg over 250 miles on my trip back from wales.

This included lots of 40mph driving behind blue rinsers, some traffic, some fun driving and lots of cruising at naughty speeds.

I love my Octy vRS, good economy, 200+bhp, and the best bit is that you get full boost from 2K to 7K rpm so I can leave it in 5th and it makes driving very easy. :)

Diesel can also achieve 200+ bhp and better ecomony, but you can't get such a lovely wide power band which I like.

ANyway i'm going on a bit, but this is the first long trip I have taken and i'm pretty happy with the car. :D
 
Back
Top Bottom