what family car gives the best mpg at 80Mph

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Tue 6 Jul 2010 13:30
what family car gives the best mpg at 80Mph - louisp

I am having difficulty in picking through manufacturers quoted mpg/green bandings to actual real world driving.

My commute and job mean that I do not drive in towns, but travel on cruise at about 80Mph on the Speedo (75Mph on sat nav) and I am trying to work out what family car (2 kids) gives the best Mpg and overall running costs.

Contenders initially were the ecoline cars such as the golf and focus, but at motorway speeds stop start and kinetic recovery do little and the engines labour as they are usually running higher revs etc.. also with colleagues driving petrol cars and getting 40mpg (2.0L 180ps A5 2010) and others driving diesels and getting 43mpg (octavia estate 2.0l 2008).

What are peoples experienced returned mpg's at motorway speeds?

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Tue 6 Jul 2010 13:44
what family car gives the best mpg at 80Mph - Glaikit Wee Scunner {P}

I get similar mpg under those circumstances from my 2l diesel Octavia hatch. But if mpg is important, drive slower.

The term "labour" usually refers to engines running at over low revs. Most larger engined (1.6l plus)cars will not be "labouring" at those road speeds in top gear.

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Tue 6 Jul 2010 13:44
what family car gives the best mpg at 80Mph - a900ss

I had a 2.0 110hp VW passat estate with the new CR engine. That did about 51MPG at 78MPH on the sat-nav, 81 on speedo. The trip computer reckoned it was doing 53/54MPG but brim to brim showed it was 51MPG (air con off though).

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Tue 6 Jul 2010 14:27
what family car gives the best mpg at 80Mph - 659FBE
Most motoring decisions are more complex and involve many factors. If I were to make a decision based on your brief, it would go as follows:

Most efficient engine suited to your task - VAG 1.9 PD. (no DPF). Thermal efficiency about 42%. (beat that).

Select a vehicle from their range with the lowest drag - Old Passat saloon is not bad, Skoda Superb possibly better as it's longer. Avoid estates. Note that vehicle weight is not a primary consideration at steady speeds.

Specify manual transmission with the highest gearing, but ensure your diesel engine is operating at somewhere near the speed of max torque (obviously you won't be using it) at 80 mph. This ensures the engine is operating in its most efficient region.

Fit low drag tyres and pump them up to the highest allowable pressure. Ensure tracking is correct.

659.
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Tue 6 Jul 2010 14:45
what family car gives the best mpg at 80Mph - louisp

so it looks like people prefer the VAG engines (and VAG cars) for motorway mileage. I currently drive Seat Leon 1.8T with LPG conversion giving me about 30mpg but lpg costs about half that of diesel or petrol. should I consider converting to LPG?

Mileage is 15K a year but I have had the leon from new (2000) and it costs £200 a year in parts plus servicing to run and I have had it from new.

So the other question comes of total cost of ownership, with me driving at 80mph on motorways for 95% of the distance, mpg is a consideration but if the vehicle costs 25% more to begin with it is a false economy.

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Tue 6 Jul 2010 14:47
what family car gives the best mpg at 80Mph - Collos25

I hope you live like I do in Germany and not the united kingdom with an overall speed limit of 70 mph.

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Tue 6 Jul 2010 14:59
what family car gives the best mpg at 80Mph - louisp

Popular press has many articles extolling the virtues of eco cars, but it is hard to draw a conclusion of running costs if you travel on motorways all day long.

I agree that estates hamper overall mpg, so a family a hatchback would be a good compromise even though it is noted that longer saloon cars give lower coeff of drag, hopefully leading to better mpg.

are the following worth considering?

www.telegraph.co.uk/earth/3336551/Top-ten-cheap-ec...l

1: Seat Ibiza, 1.4 TDI 80PS Ecomotive, diesel
2: Volkswagen Polo Bluemotion, 1.4 TDI 80PS
3: Honda Civic Hybrid 1.4 IMA ES
4: Renault Megane Sport Hatch 1.5 dCi 86 Expression 3 door
5: Citroen C3 1.6HDi
6: Ford Focus ECOnetic 1.6 TDCi
7: Renault New Laguna Hatch dCi 110
8: Skoda Fabia Estate1.4 TDI PD 80PS
9: Peugot 207 SW, 1.6 HDi
10: SMART Fortwo Cabrio

www.autoexpress.co.uk/carreviews/grouptests/252787...l
Ford Focus Econetic
Volkswagen Golf BlueMotion

the only issue being that for their tests, motorway is 60mph, which is not the speed I travel at.

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Tue 6 Jul 2010 16:04
what family car gives the best mpg at 80Mph - dieseldogg

If your annual milage is only 15 k why is it necessary to drive at 80mph on the motorway, Ok motorway speeds yes.But not necessarily 80 all the time.

PS

Purly subjective but a high geared ( 6 speed?) diesel should be best and I "thought" that the Eco whatever / Greenline models were higher geared therefore should be more economical................ but no car will or can be economical if driven unsympathetically

jat

M

Edited by dieseldogg on 06/07/2010 at 16:04

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Tue 6 Jul 2010 17:09
what family car gives the best mpg at 80Mph - ohsoslow

'Drive at 80mph for 95% distance'. Which motorway (none of the ones around here) and at what time of day / night can you do that unless you drive a BMW repmobile or white van?

Will now go and sit on the naughty step for the rest of the day.

Edited by ohsoslow on 06/07/2010 at 17:11

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Tue 6 Jul 2010 17:46
what family car gives the best mpg at 80Mph - louisp

I travel at 80 (on the speedo) which is 70 to 75mph as per various sat nav's. I now live in the north of england and there is little traffic on the road when i go to work and come home. I use cruise control all of the time and don't need to turn it off for the duration of the journey. I get passed quite a lot at the speeds I travel so I am content at the 70 to 75ish speed. just curious as to any help and expert help in keeping travel costs down :-)

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Tue 6 Jul 2010 18:21
what family car gives the best mpg at 80Mph - bimmer-driver

Reckon the new 320d Efficient Dynamics would do over 60mpg at those speeds.

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Tue 6 Jul 2010 18:51
what family car gives the best mpg at 80Mph - craig-pd130

More support for the older VAG 1.9 8-valve PD motor. I had the 130bhp variant with 6-speed manual gearbox in a B5.5 Passat which invariably gave 50+ mpg on motorway runs at an indicated 85mph.

I'm sure it would've been a bit more economical if cruised a little slower, but point-to-point averages of higher than 60mph and at over 50mpg was good enough for me :)

This car actually averaged a genuine, measured 46.5mpg in 5+ years and over 60,000 miles of motoring, which is astonishing for a 1.4 tonne family barge that was always driven, er, to make progress.

Edited to add if you wanted a more modern car, I believe Honest John regularly got 50+ mpg from a 1.6 TDCI Focus

Edited by craig-pd130 on 06/07/2010 at 18:57

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Tue 6 Jul 2010 19:01
what family car gives the best mpg at 80Mph - woodster

That really is pretty good Craig, I agree. Nice engine too. I've just done the first tank in the Octavia (2 litre 140 D) and it seems to be 44.5. That's all air- con on and no long journeys or A roads, but this is worse than the Golf I just outed. I don't know if the car's heavier although it feeels it, and it's considerably newer - 15k miles on it. Subjectively, despite being the same engine, it feels more urgent , when asked to accelerate. I very rarely go beyond 3.5k revs so I'm talking about from 1500 upwards. Anyway, what's my point? Er, none really, just rabbitting on...!

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Tue 6 Jul 2010 21:12
what family car gives the best mpg at 80Mph - bazza

To support the advice above, my Octavia 1.9 tdi will average low to mid 50s mpg driven as your requirements. Although maybe a little coa*** compared to modern common rail units, a truly great engine, I shall be picking up one of the last 105 PDS with no DPF in a year or so. I don't think you can go wrong with 659's advice above.

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Tue 6 Jul 2010 23:34
what family car gives the best mpg at 80Mph - louisp

so it looks like the VAG 1.9 in maybe the passat/octavia form would be a winner. has anyone got more info on the 320d's?

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Wed 7 Jul 2010 16:38
what family car gives the best mpg at 80Mph - craig-pd130

mid-40s is still not to be sniffed at :)

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Wed 7 Jul 2010 00:24
what family car gives the best mpg at 80Mph - Avant

I'm not sure whether you're buying new or used, but either way a BMW 3-series will cost so much more to buy in the first place than an Octavia of similar vintage as to make fuel savings academic.

If finance (purchase cost and fuel economy) is the main consideration for you, I too would suggest you go for a VAG 1.9 TDI with a 6-speed gearbox: you'll get a newer Skoda or SEAT for your money than a VW or Audi.

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Wed 7 Jul 2010 10:39
what family car gives the best mpg at 80Mph - Collos25

I wonder how far you can travel on a UK motorway at 80mph without slowing down although the limit is 70mph, whenever I come to the UK the roads are so full its sometimes impossible to get to 60mph and when you do eventually get to a higher speed its not for long.Probably if you travel at night you have more of a chance but at the rest of the time the UK roads are a nightmare.

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Wed 7 Jul 2010 13:02
what family car gives the best mpg at 80Mph - louisp

overall running costs is probably a better evaluation of what I am looking for.

Has anyone considered the entry level manufacturers such as Kia/Hyundai, the cars have low entry level costs and even have eco versions of their cars and various Diesel/petrol variants?

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Thu 8 Jul 2010 08:52
what family car gives the best mpg at 80Mph - louisp

Thanks for your help and advice

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Mon 20 Sep 2010 19:06
what family car gives the best mpg at 80Mph - plum2pudd
I fully expect most people to be incredulous at the stats I will give here but they are genuine! Just bought 1998 Octy 110 slx and recorded 78.5 mpg on trip computer at a steady 65mph over an 80 mile trip. Having owned an Octy with the same engine before I knew 60mpg was acheivable with gentle driving but never saw anything like this on trip computer!! Can anyone beat it in terms of real-world driving? I think I will try with expensive diesel next time and see if I can break 80mpg. Also had Audi A4 115PD but struggled to get this to 50mpg. My experience, interms of economy an old nicely run in 110 hp (non PD) will thrash the pants off any PD in terms of economy.
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Thu 23 Sep 2010 11:09
what family car gives the best mpg at 80Mph - k9dan

I've got one of the last 1.9Pd Octavias, for most of the above reasons (no dpf etc). If I do my best nun driving I can see an average of 75MPG !!! Driven normally averages about 55MPG. On motorway if sitting at 80ish MPG drops to 45MPG. If I go slightly slower and sit at 65mph just on the torque max then I average 60MPG. So now I generally sit at 65 turn up the jukebox and chill. I've found losing a few mph makes hardly and difference to journey time, but a big difference to my pocket. I'm still astonished at the economy for the size of the car. (it's an estate)

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Thu 23 Sep 2010 22:42
what family car gives the best mpg at 80Mph - slidejules

I'm with you guys... I used to have a 2000 (W) Octavia SLX tdi 110... you could drive that thing to the moon and back on ten quidsworth of diesel. My record was one night where I did an overnight trip from Twickenham up to Barrow in Furness. Got onto the start of the M3, hit cruise control at 54mph, then didn't touch the pedals until pulling off the M6 up at junction 34 or 35, whichever it is. My average mpg was over 80! Astonishing beast... I'll never forget that... two hundred and something miles, and the fuel gauge said I'd only used quarter of a tank...

Of course the next day I drove down in more of a hurry and undid all the good work. But yeah, that thing was amazing.

I replaced it with a golf gt tdi 115, 6 speed, which seemed to average about 55mpg whether I drove it at 60 or 80. 60 was too slow for 6th gear and too fast for 5th to get crazy economy. Still, great car.

Yup, vw tdi lumps are the nuts :-)

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Mon 20 Sep 2010 19:20
what family car gives the best mpg at 80Mph - mrnikko

I have a new shape Vauxhall Astra which I use on the motorways in the north of England, and like your question I cruise at 75 to 80 regularly with cruise control on. After 14,000 miles its returning 48 to 55 mpg depending on speed and conditions. Most people avoid Vauxhalls and I will admit I was one of them but the new Astra is worth a good look at and leave any preducies at home. I think all of the Vauxhall dealers will offer good deals at present.

Also to the posts re using cruise control up here in the north on the M6 and into Scotland on the M74 you can use cruise for miles at a time, current longest is M55 junction on the M6 to Junction 41 near Penrith with-out knocking cruise off.

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Mon 20 Sep 2010 19:24
what family car gives the best mpg at 80Mph - SteveLee
If fuel economy is so important to you then why not drive at 65 mph instead?
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Tue 21 Sep 2010 00:21
what family car gives the best mpg at 80Mph - OldSkoOL

I burn oil nicely in my 335d on the m-way.

An easy 47mpg recently on a trip down the m1. But of course, if you start zipping around traffic and not particuarly driving efficiently it drops to about 43/44mpg. And persistent abuse of the right pedal, it will fall to just above 40.

But having said that, put it on CC and the instant MPG needle sits bang on 50mpg so i reckon if i just maintained a speed it would hit 50.

So it strikes me as odd that many of these 2.0 110bhp cars are only doing 40-50mpg.

I advised a colleague recently to buy an old peugeot diesel, 1.9tdi. He gets an easy 60mpg in that. And it's an estate.

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Wed 22 Sep 2010 19:58
what family car gives the best mpg at 80Mph - plum2pudd

Yeah but bigger engines usually much torquier and can cruise in higher gear with much less effort than smaller engine. My Dad has Renault 1.5dci and long term average is only 55mpg whereas mine from the Octavia 110hp is now 66.5mpg! 60mpg piece of cake. 70 not hard on gentle cruise but my personal holy grail is still 80mpg over a reasonable distance (say 30+ miles).

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Thu 23 Sep 2010 11:15
what family car gives the best mpg at 80Mph - Sofa Spud

The national speed limit is 70 on motorways and 60 on single carriageways. If you think you're exempt from those regulations you should seriously reconsider whether you should be driving a car at all!

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Thu 23 Sep 2010 18:44
what family car gives the best mpg at 80Mph - tdc

The national speed limit is 70 on motorways and 60 on single carriageways. If you think you're exempt from those regulations you should seriously reconsider whether you should be driving a car at all!

......and only 50 on single carriageways if you`re in a van or in a car towing a caravan or trailer.

But hey,they allow you a bit over the limit surely,just under 80 on the clock in a 70 never posed a problem for me yet.

You could always switch to a bike...speed,power&mpg

...but my days of 150+ in a 60 are over!

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Fri 7 Oct 2022 05:26
what family car gives the best mpg at 80Mph - Jimijojimbob

Hi I would look for a Mercedes E class I drove the E350d with adblue technology and a 9 speed auto gearbox at 77mph true she pulled 1500rpm and comfortable managed 50mpg+ on motorway journeys.

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Fri 7 Oct 2022 06:12
what family car gives the best mpg at 80Mph - badbusdriver

Hi I would look for a Mercedes E class I drove the E350d with adblue technology and a 9 speed auto gearbox at 77mph true she pulled 1500rpm and comfortable managed 50mpg+ on motorway journeys.

I suspect after 12 years the OP will have already chosen.

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Fri 7 Oct 2022 12:08
what family car gives the best mpg at 80Mph - Engineer Andy

Hi I would look for a Mercedes E class I drove the E350d with adblue technology and a 9 speed auto gearbox at 77mph true she pulled 1500rpm and comfortable managed 50mpg+ on motorway journeys.

I suspect after 12 years the OP will have already chosen.

My suspicion is that the previous poster to you BBD does not have honourable intentions, given previous instances of people with (almost) random usernames posting in long-dead threads.

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Fri 7 Oct 2022 20:56
what family car gives the best mpg at 80Mph - Ethan Edwards

Tesla Model S.. Uses zero petrol at 85mph. You could even find one several years old, almost as old as this thread.

Edited by Ethan Edwards on 07/10/2022 at 20:58

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Sat 8 Oct 2022 23:43
what family car gives the best mpg at 80Mph - John F

For high miler high speed motorway drivers it's worth looking at a car's drag (Cd) figure. If fuel economy is important, don't consider one above 0.3. (e.g. Aston Martins - they may look sleek, but they're not.) The best are modest sized electric cars, e.g. Hyundai Ionique or Toyota Prius, around the .25 mark. Some large cars are surprisingly good - e.g. Audi. Forty years ago their 100 was 0.3 - the A8 is even sleeker.

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