Will a new car engine break in and gain mpg?
03-01-2011, 01:23 PM
#1
Will a new car engine break in and gain mpg?
I recently bought the wife a brand new quashqai +2. We went for the 1.5 diesel as it's not to be a racing machine. I was promised 50 mpg.
We've now done 1600 miles say and the mpg is around 30-31 mpg. Has been below that in the cold.
So will this engine "break in" and improve? Or are we seeing worse mpg due to the cold?
We've now done 1600 miles say and the mpg is around 30-31 mpg. Has been below that in the cold.
So will this engine "break in" and improve? Or are we seeing worse mpg due to the cold?
03-01-2011, 01:27 PM
#2
I often hear people saying about engines "freeing up" etc, but when I build an engine I can spin the crank with 2 fingers anyway, so I really am not convinced that this happens to any great extent, IME engines lose power and economy with age not gain it (due to losing ring seal and valve seal)
The only exception being the first few hudnred miles while the rings bed in and seal improves, but once this has happened its then a drop in power from there on in only IME.
I would imagine in your case, you are driving with a lead right foot the whole time cause you have such a small engine in a relatively big car, stick it on the motorway at a held 70mph and it will probably see 50+ as promised.
The only exception being the first few hudnred miles while the rings bed in and seal improves, but once this has happened its then a drop in power from there on in only IME.
I would imagine in your case, you are driving with a lead right foot the whole time cause you have such a small engine in a relatively big car, stick it on the motorway at a held 70mph and it will probably see 50+ as promised.
03-01-2011, 01:42 PM
#5
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tbh i think you will be lucky to get anywhere near that, a megane 1.5 dci which is made of recycled cardboard will just say get 50 when driven cautiously, the cold spell will have some influence on what you are getting at the minute though
03-01-2011, 01:45 PM
#9
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03-01-2011, 01:47 PM
#11
A what? And replaced with what?
look here... http://www.buyacar.co.uk/nissan_qash...dr_31728.jhtml
Not even close!
03-01-2011, 01:49 PM
#13
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it wont make a difference if its Ł1 a litre, or Ł10 a litre, you will still get the same amount miles out of a gallon. i was being sarcastic, and thought i had put one of these 
, at the end, but evidently, i didnt 
so one of these for me
, at the end, but evidently, i didnt so one of these for me
03-01-2011, 01:52 PM
#20
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03-01-2011, 01:55 PM
#22
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03-01-2011, 02:14 PM
#23
Testing the future
I often hear people saying about engines "freeing up" etc, but when I build an engine I can spin the crank with 2 fingers anyway, so I really am not convinced that this happens to any great extent, IME engines lose power and economy with age not gain it (due to losing ring seal and valve seal)
The only exception being the first few hudnred miles while the rings bed in and seal improves, but once this has happened its then a drop in power from there on in only IME.
I would imagine in your case, you are driving with a lead right foot the whole time cause you have such a small engine in a relatively big car, stick it on the motorway at a held 70mph and it will probably see 50+ as promised.
The only exception being the first few hudnred miles while the rings bed in and seal improves, but once this has happened its then a drop in power from there on in only IME.
I would imagine in your case, you are driving with a lead right foot the whole time cause you have such a small engine in a relatively big car, stick it on the motorway at a held 70mph and it will probably see 50+ as promised.
as you are also no doubt aware, many oe management systems use adaptive fuelling (and ignition) that improve with time and mileage from new.
having had a brand new car at least every 6 months for the last 10 years, IME the economy will definitely improve. however, it seems unlikely to improve between what you are getting now and what you are expecting (although expecting the EC Combined cycle average is totally unrealistic in everyday driving. even the urban cycle is optimistic unless you live in the fens and drive like a vicar).
03-01-2011, 02:14 PM
#24
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Top gear done one once I think it was a smart car and they said that the mpg was around the 50 Mark but everyone was only getting 35mpg but only 40 the most but smart said that it would be due to tyre pressures correct and the weather confound and loads of other factors to the claimed mpg.
03-01-2011, 02:22 PM
#26
It Wasnt Me!
Chop, any new car i've drove i've definately found the engine to free off after ~800 miles, it's a hard one to explain but they seem to rev free'er and i'd say you definately use less throtle. It'll be to do with the ring's bedding in i'd guess, as bearings don't actually bed in. I'd say it's definately not going to have an effect on it now it's done 1600 miles, the only thing that can improve it now is ambient temp!
03-01-2011, 02:26 PM
#27
............
From experience Chop it'll improve, but not by as much as you hope
Most of my cars have only ever seen the manufacturers quoted figues when driving on the motorway, in a contraflow, at 50 mph
Most of my cars have only ever seen the manufacturers quoted figues when driving on the motorway, in a contraflow, at 50 mph
03-01-2011, 02:31 PM
#29
as you are also no doubt aware, many oe management systems use adaptive fuelling (and ignition) that improve with time and mileage from new.
Last edited by Chip; 03-01-2011 at 02:32 PM.
03-01-2011, 04:01 PM
#30
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A diesel won't even b warmed up with 1600 miles, every single car I've known from new has improved, but the diesels have taken a huge amount more miles as they wear so slower, hence doing intergalactic mileages, and the fuel being a oil.
Diesel fuel is also altered in the winter months, which does lead to lower mpg, has been for years.
Far better quality oils also slow the bedding in process, which is mainly the rings.
tabetha
Diesel fuel is also altered in the winter months, which does lead to lower mpg, has been for years.
Far better quality oils also slow the bedding in process, which is mainly the rings.
tabetha
03-01-2011, 04:59 PM
#34
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You are never going to see 50mpg out of a huge brick of a car like that with a tiny engine I'm afraid. I will see if I can find the link, there was a very enlightening article about how the mpg figures are achived, ie it is done on a rolling road using microscopic throttle adjustments to get to the desired speed for the mpg calculation. It's borderline lies the way they achive and claim mpg figures, but there you go.
My brother had a 1600cc petrol Mondeo mk1, it was hideous on fuel as you were constantly thrashing it to make it move!
Oh, Fiddy, sorry but you were massivly busted there! Take yourlike a man
My brother had a 1600cc petrol Mondeo mk1, it was hideous on fuel as you were constantly thrashing it to make it move!
Oh, Fiddy, sorry but you were massivly busted there! Take your
like a man
03-01-2011, 05:17 PM
#35
I was expecting 40 on a day to day basis and perhaps 50 on a run.
As per my other thread I went to the dealer today and they were most surprised at the economy. The salesman himself has been running one and sees a totally different economy. Usually up to 50.
Wil I know what you mean about fudging the figures but I expect more than 27-31!
03-01-2011, 05:22 PM
#37
st170 breaking
my 06 octacia got faster and much better on fuel once the miles were up
i did 100k plus a year tho so easier to notice when you fill up every other day but it was only a few k or motoring before it was as it should be, also it used much more fuel when it came up for service (variable 30k ish)
i did 100k plus a year tho so easier to notice when you fill up every other day but it was only a few k or motoring before it was as it should be, also it used much more fuel when it came up for service (variable 30k ish)
03-01-2011, 05:27 PM
#38
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cars rarely do the mpg as stated in adverts or so on as when the tested for the mpg's its in a nice hanger or track etc so the things of everyday life are not accounted for i.e traffic,road surfaces,winds,weight in the car etc etc
03-01-2011, 05:27 PM
#39
What sort of power is the 1.5 dci? My Pug 406 2.1TD still achieves 45mpg no problem, putting out something like 110bhp and 230ft/lb of torque and it's barge like 
If i emptied out some of the crap i'd probably gain a few more mpg's 
If i emptied out some of the crap i'd probably gain a few more mpg's
03-01-2011, 05:28 PM
#40
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I have the tech sheet for how Euro mpg is determined somewhere - if I can find it tomorrow when I'm back at work I'll put some of it on here.
Suffice it to say that you stand little or no chance of achieving the published figures in real-world motoring.
Suffice it to say that you stand little or no chance of achieving the published figures in real-world motoring.