Ocsid
Member Since: 29 Nov 2005
Location: Hampshire
Posts: 255
  
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A major cause of the higher fuel consumption when towing a caravan is the aerodynamic drag, so differences to towing a RIB or trailer are expected.
This was brought home when I changed to a heavier caravan but one with radiused corners, as opposed to square and noticed an "improvement". Also the headwind is seen to have a marked effect.
I expect we are talking "indicated" mpgs off the cars readout and these are optimistic compared to tank topping checks.[Not that usually I get much chance to tow all of a "fill" to be able to compare]
Currently over 5029 towed miles with the latest van and the Disco at 21K miles the indicated towing mpg is averaging 21.62.
Towing in hilly terrain where things are free flowing seems to make no difference, clearly we recover the pain of towing up hill whilst rolling down.
When towing its the stop start and slowing and accelerating like with an over abundance of roundabouts that really kills fuel economy.
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 30th Nov 2009 3:35 pm |
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mzplcg
Member Since: 23 Jun 2009
Location: Gone
Posts: 1087
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Have you ever tried one of those wind deflectors? If drag is a really major factor then would it be helped with one of those do you think?
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| 30th Nov 2009 3:45 pm |
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Ocsid
Member Since: 29 Nov 2005
Location: Hampshire
Posts: 255
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mzplcg wrote:Have you ever tried one of those wind deflectors? If drag is a really major factor then would it be helped with one of those do you think?
No but on the ferry coming back from France another fellow D3 driver with caravan had LR's top box.
Anyway he said he only had it for this particular holiday and was going to sell it on but was so impressed how much better MPG he got than before so was going to keep it.
Cost of it will buy a fair bit of Diesel and I could not get it in garage with the bars let alone the box so not following that route.
Could simply be down to the free flowing long distance roads.
And undoubtedly drag is a major factor, that I am convinced about.
Trouble with these deflectors is getting them at the optimum position/angle for your normal towing speed.
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| 30th Nov 2009 5:15 pm |
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Mollers
Member Since: 01 Jul 2009
Location: Mighty Penryn - Cornwall
Posts: 116
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Ocsid wrote:A major cause of the higher fuel consumption when towing a caravan is the aerodynamic drag, so differences to towing a RIB or trailer are expected.
.
I agree, but still surprising considering the TT weighs in at 1000kg and the boat nudges 2000kg fully fuelled.
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| 30th Nov 2009 6:54 pm |
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roverdrive
Member Since: 08 Oct 2009
Location: Wirral
Posts: 181
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Towing 1600kg tintent from Wirral to Ashburton with the old D3 XS Auto gave 22/23 mpg assuming 55/60 mph all the way.
Only towed the tintent up to Coniston with the new D3 HSE Auto, but that was giving similar figures on an engine with 1,000 miles on the clock.
The old XS got 26mpg with the 3.5 tonne tipper trailer on the back, but that was probably only an all up weight of 2 tonne at the time, so aerodynamics play a huge part, as does driving style.
I constantly get 2mpg more than SWMBO just down to different driving style and no tailgating!!
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| 30th Nov 2009 8:58 pm |
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kevi
Member Since: 18 Mar 2006
Location: in the rhondda valleys
Posts: 945
 
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Best thing is DON'T LOOK  Practice safe eating - always use condiments.
2 Too many seats now
No trouble so far
tow pack, tasmods sills
IT goes without saying that you should never have more children than you have car windows
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| 30th Nov 2009 9:13 pm |
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fast but dim
Member Since: 12 Aug 2009
Location: NW
Posts: 67
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my 97 defender 90 does 28mpg at 55-60, towing or not.
the d3 does 27, 25ish towing. saying that, the d3 wants to tow at 70 (6th), and i'm not knackered after 150 mi.
imho the disco pullls better on the Mway 90 tows better off.
just buy red derv, 
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| 1st Dec 2009 10:25 pm |
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G1BB0
Member Since: 27 Aug 2008
Location: Devon
Posts: 110
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Hi
I get 29mpg average solo and about 26.5mpg towing our large 6 berth twin axle caravan. This is in a manual and i would agree with earlier comments - tend to stick in 5th gear rather than 6th as I find 6th is just too high and the engine labours.
Surprised you lost 10mpg with a two berth van though, although I guess the wind strength will play a part. MY11 Disco 4 SDV6 HSE
Previously 06MY Disco 3 TDV6 HSE
Previously 06MY D3 TDV6 7 st
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| 2nd Dec 2009 4:12 pm |
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nigel207
Member Since: 26 Mar 2009
Location: Nottinghamshire
Posts: 1359
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Hey G1BBO,
What do you get when you have to go back up the hill?
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| 2nd Dec 2009 4:19 pm |
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AWD man
Member Since: 03 Jul 2009
Location: In Drag
Posts: 831
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Mine dropped from 29mpg to 28mpg (with 200miles on mileometer) towing a 4 berth Challenger from Swindon to the Gower (motorway all the way) at a steady 65mph on cruise.
Manual in 6th BTW 57 RRS TDV8
BAS Map
D3: Gone but not forgotten
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| 2nd Dec 2009 4:34 pm |
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al cope
Member Since: 08 Nov 2005
Location: Oldbury, WM
Posts: 10355
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towing definately seems to hit the auto's more so than the manuals.
But then there's no dodgy clutch to  up 
Al Volvo XC90 B5 Plus Dark
Gone - MY18 D5 HSE - Corris on 22's with Black Pack
Now gone - MY16 D4 SE Tech, Loire Blue, Almond Leather, Privacy, plus some other goodies.
Old - MY12 D4 SDV6 XS Auto - Ipanema Sand with Almond Leather - Plus other niceties, and D4.com sticker
Older - D3 TDV6 XS Auto - Lugano Teal with Almond Leather, 20" Stormers, Shiny Tailpipes, DVD/TV - and obligatory D3 sticker
Ancient - D3 TDV6 S - Tonga with Ebony, 20" Stormers, satnav & DVD
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| 2nd Dec 2009 5:06 pm |
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DiscoDunc
Member Since: 08 May 2006
Location: Bristol
Posts: 16390
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I get about 18mpg towing twin axle caravan (2000Kg ish) - it gets a bit better (20mpg) if I leave it in sport mode and manually change to 6th when down hill - but most of the time I just leave it in sport.
I get about 22 normal driving so not a great difference. Duncan
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If I'd known I was going to be so thirsty this morning I'd have drunk more beer last night.
FFRR Autobiography 4.4 SDV8 MY17
D4 HSE MY13 SOLD
FFRR 3.6 Vogue TDV8 SOLD
D4 HSE MY10 SOLD
D4 SE TECH MY15 SOLD
D4 XS MY12 SOLD
D4 HSE MY10 SOLD
D3 HSE MY06 - Re-Cycled Worldwide
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| 2nd Dec 2009 6:00 pm |
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G1BB0
Member Since: 27 Aug 2008
Location: Devon
Posts: 110
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Quote:What do you get when you have to go back up the hill?
That includes hills! Towing from Cheshire to South Devon (lots of hills!) last summer we averaged 26.9 mpg, worked out by brimming the tank rather than trusting the onboard computer.
On a motorway journey without the caravan we can get 32-33 mpg without too much trouble - and no I'm not a steady eddy either - I like to make progress the same as everyone else 
Seems to be a big difference between different vehicles - I certainly don't drive for economy but my D3 just seems to give reasonable mpg returns. One thing I do keep an eye on is tyre pressures and tend to run at the laden pressures all the time - makes the ride a bit firmer but saves having to change pressures all the time and doesn't seem to adversely affect handling or tyre life - got 33k out of the last set of tyres. MY11 Disco 4 SDV6 HSE
Previously 06MY Disco 3 TDV6 HSE
Previously 06MY D3 TDV6 7 st
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| 2nd Dec 2009 6:00 pm |
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nigel207
Member Since: 26 Mar 2009
Location: Nottinghamshire
Posts: 1359
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G1BBO,
I too have a manual version, and towing our modest weight (1440 kgs) caravan, I'm lucky to get much more than 20, despite being light of foot. Although I've not had the car that long, when we went to the South of France in the summer I did stick at between 60 and 65 mph in 6th, but almost without exception we were heading into a fairly strong headwind. I couldn't believe that we were battling into it going south, and two and a half weeks later, we were battling into it travelling north!
We're away next week to York which is a good, easy run from here. I'll try sticking to fifth, and see how we get on.
Oh, and like you, I run with the tyres inflated for a full load.
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| 2nd Dec 2009 6:47 pm |
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G1BB0
Member Since: 27 Aug 2008
Location: Devon
Posts: 110
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nigel207
Interesting... I do use 6th when towing but only when there is not much load on so when travelling on level ground or downhill. Tend to drop to 5th as soon as I hit a hill, even a slight incline, just to avoid labouring the engine and rarely use 6th when towing on single carriageway A and B roads. I don't know if that makes any difference to mpg though, or even if it does the vehicle any good - my D3 seems to be reasonably economical anyway.
As I say, I think so much of economy seems to be down to different vehicles - no real reason why that should be so I guess, but it certainly seems to be!
And, to be honest, I would care even if it did 10mpg less - its a great vehicle and if I was that worried about fuel economy then I would drive something else! MY11 Disco 4 SDV6 HSE
Previously 06MY Disco 3 TDV6 HSE
Previously 06MY D3 TDV6 7 st
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| 2nd Dec 2009 8:43 pm |
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