mpg on p38 deisel

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Datatek said:
I reckon a lot of the variation in mpg is between proper brim to brim checks and people quoting the hopelessly inaccurate calculated consumption figure from the computer:rolleyes::rolleyes::rolleyes:
According to the computer, mine does 27 to 29mpg around and about and up to 34 mpg on the autoroute. See my earlier post for the accurate figures:D:D:D
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Have to say I've never tested the P38 properly so don't know about the computer - got to fill up today, so I'll check it properly this round! However - not all computers are useless.. my BMW used to be within 1mpg and my Alfa used to be consistently accurate to within 0.2mpg! (something which always amazed me - not least because it was an Alfa!!!)

Matt
 
Beast o Bodmin said:
it allways amazes me with a thread like this that no one seems to realise you need a small doisel pop out car if ya own a rangie...
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Why would anyone go out in a "small pop out car" when they have the comfort and tank like safety of an airconditioned Rangie? A "small pop out car" for when the Rangie breaks down, now that's another matter:D
 
Mt 2.5 DSE used to average around 24-25 around on local driving and up to 29-31 on a run. When I recently replaced the DMF/clutch (got rid of the rough idle problem when hot) the consumption increased to 25-27 local. On a run (yesterday) I was getting 31 mpg driving it hard - it has a power box fitted and I was doing a lot of overtaking and also cruising at around 80 mpg (sorry I meant 70, 'cause 80 is illegal). Previous day I was taking it easy on the same run of 65 miles with heavy traffic slowing me down, so had a light foot and it actually gave me 35 mpg. However, if you're going to buy a P38, it would be wise to either have your own diagnostics (I have Rovacome Lite)or know someone who has them and they also need a lot of preventative maintenance. If you need to take one to the main LR stealer, you need a very deep pocket. If you can fix them yourself, they are a magnificent vehicle.:)
 
rrdiver said:
Mt 2.5 DSE used to average around 24-25 around on local driving and up to 29-31 on a run. When I recently replaced the DMF/clutch (got rid of the rough idle problem when hot) the consumption increased to 25-27 local. On a run (yesterday) I was getting 31 mpg driving it hard - it has a power box fitted and I was doing a lot of overtaking and also cruising at around 80 mpg (sorry I meant 70, 'cause 80 is illegal). Previous day I was taking it easy on the same run of 65 miles with heavy traffic slowing me down, so had a light foot and it actually gave me 35 mpg. However, if you're going to buy a P38, it would be wise to either have your own diagnostics (I have Rovacome Lite)or know someone who has them and they also need a lot of preventative maintenance. If you need to take one to the main LR stealer, you need a very deep pocket. If you can fix them yourself, they are a magnificent vehicle.:)
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I didn't know cruising at 80 mpg was illegal:doh::doh::doh:Now 80mph is a different matter in the UK:eek::eek::eek: but toally legal here in France on the autoroute:D:D:D
 
Datatek said:
With the auto, I suspect that it's more to do with speed than revs, the torque converter locks at just over 50mph and thats when the best fuel consumption figures start to appear. Running around and about, a lot of the time it's below lockup speed and the fuel is just being wasted in torque conveter slip. That doesn't answer why the manual version seems to do consistantly worse on fuel consumption tho.
I reckon engine efficiency is at it's peak at around 3000 rpm.
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I reckon you're about spot on, just a whisker under 3000rpm seems to be the magic number with the manual, but push it much more and the drop off is pretty steep!:eek:
 
Datatek said:
With the auto, I suspect that it's more to do with speed than revs, the torque converter locks at just over 50mph and thats when the best fuel consumption figures start to appear. Running around and about, a lot of the time it's below lockup speed and the fuel is just being wasted in torque conveter slip. That doesn't answer why the manual version seems to do consistantly worse on fuel consumption tho.
I reckon engine efficiency is at it's peak at around 3000 rpm.
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Could it be that the auto cruise has better throttle control for a set speed, than a right footed speed controller??????
 
Interesting stuff,I'd expect the auto to use more fuel than the manual,I won't be towing + most of the time it will be on b roads rather than the motorway,I'm not expecting miracles due to the size or weight but i don't want to end up with somthing doing under 20mpg as i might as well look at petrols
 
Chaps i always thought autos were heavier on fuel than manuals, i am on my 2nd p38 my first was a manual dhse with chip and i tend to be very heavy footed in mine, and it returned 25-30 mpg my current p38 is a auto but also chipped returns from 27-32 mpg. i have worked out my drive to work on many occasions in my different cars, i have to to try and convince the missus my cars are economic, once i know the truth i can then exagerate from there. the dhse auto with a chip i have now is better on fuel than my last 5 cars, which i have had in the last 12 months.
better than a
  1. 4x4 cosorth
  2. 2.5 skyline
  3. 2x scoobies
  4. manual dhse
Far better than i had thought, and not much worse than the missus focus if i concentrate on driving economically
 
wreckhunter said:
Interesting stuff,I'd expect the auto to use more fuel than the manual,I won't be towing + most of the time it will be on b roads rather than the motorway,I'm not expecting miracles due to the size or weight but i don't want to end up with somthing doing under 20mpg as i might as well look at petrols
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Most of my around and about mileage is on narrow twisty roads. No traffic here though:D:D:D
 
kernowdragon said:
Even if you accept that the computer figures are generally inaccurate, hence my miles/litres calculation, the one thing they do seem to show is that it is actually more fuel effective to run at higher revs, as others have said, mine certainly seems to do better mpg at 65 than at 55, a bit of a reverse on the usual theory.
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I have found my DSE seems to get better mpg if i drive it at 65 to 70 mph than 55 mph and if i get away quicker than normal
 
Nathan, I am getting 18 round the houses and 22 on a decent run at around 80 mph, on motorways etc. and I ain't got a feather light right foot.
Mind you, if I whack it round to 120+ it drops to around 10mpg.
 
hey there
i have a 2001 p38 2,5 hse and on the long road i have got it up to 30mpg and was sitting at 120/130kmph and revs around the 2800rpm.she held this for over an hour and thentraffic slowed me down to around the 28mpg,
as for town driving youll be lucky to get 20/23mpg and thats about the best youll get, also the p38 is a lot heavier and you have to boot it to get her to respond but once she up there she is happy.
cheers john
 
Just got my first 2.5 dhse and impressed with the comfort but not the MPG I'm getting 19 mpg back and too work. Not been on a decent run yet. I was told this has been chipped but not sure what that is supposed to mean, can any one enlighten me.
 
It has been chipped to increase the power. Only way to do that is to give it more fuel. If you use the power you will use more fuel. Simple as that.
 
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