Hi,
Been looking for a new mid-mpv, at my price range I can get a nearly new 1.6 or 1.8 Zafira or a bit older diesel, pretty much the same situation on the other cars I have looked at.
I am keen to get as fuel efficient car as I can, my current Picasso gives around 35 mpg on longer trips but reading some reviews it seems that in some cases 1.8 or 2.0 cars can get better fuel efficiency and in some cases better than their equivalent 1.6. Also my Picasso (1.6) seems a little underpowered and I am concerned that the others will be the same (or worse as they will be bigger/heavier) so perhaps I need a bigger engine model.
So does a bigger engine really mean worse economy, or because there is more power there is less need to thrash it and therefore overall economy is about the same (or better)?
Cheers,
Peter
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Frequently a larger engine means greater torque and the ability to pull higher gearing, hence improved economy. Suspect this is only relevant on longer journeys though.
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A long time ago,Motor magazine tested four makes of cars which were available with more than one size of engine.They drove them in four different conditions,ranging from city-centre stop/go to motorway.On all four cars,the only time the economy was better on the smaller engined cars was in city-centre stop/go.
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>>So does a bigger engine really mean worse economy -
1) Variations depending on make etc but in broad principle between say 1800 and 2ltr generally the 1800 may be more economical around town / short journeys - on a motorway @ constant speed there could be little in it. If you are fully laden then the 2 ltr could be more economical.
>>Because there is more power there is less need to thrash it and therefore overall economy
is better
YES - also thrashing a 1600 can give you more mechanical issues than say a 2 ltr which is not stressed and driven at the same speeds / rate of acceleration etc
If however comparing a 2 ltr & 3 ltr - the 2 ltr will be less expensive to run in nearly all journeys
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My 3.0 litre Peugeot has almost identical mpg figures to my last 2.0 litre turbo Peugeot on motorways. (late 30s early 40s) It's stop-start traffic that really hurts the wallet.
A bigger engined car is often dragging around more electric toys, gadgets, heated this, automatic that and wotnot
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When we went from a 316i to a 318i we got an extra 3mpg in general driving.
I've now got a 323Ci (which is a 2.5 litre) and it gets just 2 mpg less than the 316i did, and I do tend to cane it quite regularly. :-)
Blue
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Surely some of the answer will depend upon your individual driving style? If you are a relatively gentle driver, you might get better mileage from the smaller engine variant.
But if you prefer to ?make progress? (to steal a phrase from ?roadcraft?) when you drive (and I know I do), the bigger engine would be better. I find that when I?m in a hire car (generally the hire companies buy the smallest engine variant of whichever model they provide) I still expect to make the same rate of progress as my normal wheels (200bhp) , so I am generally thrashing the engine as a consequence. Last weekend, open roads of Scotland, and I only got about 30mpg from a Focus 1.6 auto (which I thought was absolutely gutless). I am sure I?d have got a better mileage with a bigger engine, because I wouldn?t have used kickdown so often.
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When we went from a 316i to a 318i we got an extra 3mpg in general driving.
A work colleague traded in his 320i for a 330i (both E46 models) and got an extra 2 mpg!
I went in the 330i as a passenger several times, and I still struggle to comprehend how such a genuinely quick car can crack 30 mpg in daily use. The 320i only managed late 20's.
Cheers
DP
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>>So does a bigger engine really mean worse economy, or because there is more power there is >>less need to thrash it and therefore overall economy is about the same (or better)?
My Honda Civic (year 2000) - 1600cc 125Bhp gets 36 mpg overall (manual calculation brim to brim)
My D-i-L Honda Civic (year 2005) 1800 cc 140BHP gets 42mpg overall (on-board computer)
She has more power and more mpg - technology moves on obviously
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In the early 1990s I used to have a 1.3 litre VW Jetta and would often long for more power for overtaking.
So I bought a 1.6 Jetta TX and not only did I get the additional oomph, but about a 20 per cent improvement in fuel consumption.
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What\'s for you won\'t pass you by
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If the larger engined version of a car is higher geared and doesn't weigh much more than the smaller engined version, it might well be more economical if driven in a similar manner. As soon as one starts making use of the extra power or torque the economy is likely to suffer.
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FB: Are you sure the DiL car was 1.8? Surely the 2005 Civic was in 1.6 or 2.0 capacities only, in petrol. The 42 mpg sounds right for the 1.6, but my 2.0 Civic manages only 35 in favourable (non-urban) conditions.
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My 2.0 TDCi Mondeo does 41 mpg on short journeys in winter and 47 mpg in summer
SWMBO's 1.8 TDDi Focus does 38 mpg short journeys in winter and 42 mpg in summer
So I have a bigger engine and a bigger car that has better fuel economy.
I can't compare long journeys with SWMBO cos she never does any, but I get 56-59 mpg on the motorway at 70 mph and over 60 mpg on A-roads @ 60 mph ;0)
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Ignoring acceleration, the power required to propel a car is largely governed by the car body (aerodynamics) and the rolling resistance of the tyres. As the mass flow rate of the fuel into the engine is proportional to this power, if the engine and powertrain efficiency is comparable, the size of the engine won't have a huge bearing on the mpg.
The equality of efficiency between engines/drivelines is most nearly acheived when two similar engines are being compared - say if the 2 litre engine just has slighlty bigger bores than the 1800. However, if the 2000 is also a six cylinder engine driving a more lossy transmission, then the comparison is not valid, and the 2 litre will give poorer economy.
Number_Cruncher
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If I drove with economy in mind (well, more in mind because I can't see the point of using fuel unnecessarily), my Porsche 993 (272 bhp) used to manage 30 mpg if there was plenty of motorway driving. My Cooper S (170 bhp) happily manages areoung 35 mpg without my trying too hard. And they both were/are driven to give the same performance (you'll think quite a generalisation, maybe, but I know what I mean).
BMW 6-cylinder petrols, especially in the 3 series, seem exceptionally economical. On paper the 335i is awesome - in very performance measurement. Diesels good too. I'm looking forward to great economy from my 320d. Anyone here run a 320d? What mpg do you get?
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If its the zafira your looking at I can tell you hand on heart and experience a planty that the 2.0 is every bit as efficient as the 1.6 and in pretty much every circumstance is better. I used to drive taxis made up of a fleet of zafiras with all types from 1.6 basic models to the 2.0 higher spec ones (not the gsi) also drove the td.
I didnt quite like the derv variety though, something didnt quite work with it, one of those things I couldnt put my finger on but I suspect it ws badly geared.
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