Wex
Member Since: 16 Apr 2007
Location: Knackeragua
Posts: 5173
  
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Quote:The uphill bit may have merit (Hamble must be closer to sea level than Leicestershire) but only by a 100m max - could that account for the energy 3mpg over 150 miles equates to
I haven't a clue what the gradients are like , not trying to be a smartase here , even thought there may be an approx 100 m height diffrence from A to B but whats in between., rolling hills roads , steepish climbs , etc ?
After ruling this out then I'm stumped 
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 17th Jan 2008 2:49 pm |
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NHR
Member Since: 13 Dec 2007
Location: Warsaw
Posts: 923
 
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Are the ditances and route taken on each part of the trip really identical? Over 150 miles the effect of one way streets, diverging carriageways, etc may cause a difference.
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| 17th Jan 2008 2:56 pm |
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simonsi
Member Since: 14 Oct 2007
Location: Auckland
Posts: 1264
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Discowex wrote:Quote:The uphill bit may have merit (Hamble must be closer to sea level than Leicestershire) but only by a 100m max - could that account for the energy 3mpg over 150 miles equates to
I haven't a clue what the gradients are like , not trying to be a smartase here , even thought there may be an approx 100 m height diffrence from A to B but whats in between., rolling hills roads , steepish climbs , etc ?
After ruling this out then I'm stumped
True but I'd think you would lose on the uphill bits, gain something on the downhill bits so the net effect of the overall height gain would be relevant somewhere and there MUST be more height gain than loss over the trip back as I end up higher.... but have better consumption 
Prevailing wind blowing me uphill???? Cheers
Simon
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| 17th Jan 2008 2:58 pm |
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Wex
Member Since: 16 Apr 2007
Location: Knackeragua
Posts: 5173
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Stumped
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| 17th Jan 2008 3:01 pm |
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wolster
Member Since: 07 Dec 2007
Location: various
Posts: 352
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 Prevailing wind in UK is from the SW.
5mph wind pushing you home and slowing you there may have an effect?
Just a thought 
All of engine effort doesn't go into fighting wind resistance but a lot does. Especially the faster you go. Travelling at 70mph could conceivably be equivalant to 73mph into a 5mph wind and 67mph with a following one.
     What if the "Hokey Cokey" really is what it's all about?
'54 TDV6 Auto SE, Silver, Leather, HSE Wheels, Alpine Roof, Light Guards, Black Side Tubes, Tints.
Y 110 County Commercial, White, just bought it... watch this space for added bits!
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| 17th Jan 2008 3:40 pm |
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Bill Wright
Member Since: 03 Nov 2007
Location: Glorious Devon
Posts: 3254
  
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As per Wolster's suggestion but with an amendment ('cos I wasn't looking at the gear stick position!):
75mph 5th gear 2 miles 29.1 mpg 
75mph 6th gear 2 miles 27.6mpg
How can that be? It was tested on a flat road.
Bill Wright Never take life too seriously. Nobody gets out alive anyway.
D4 SDV6 SE Tech Kaikoura Stone MY15.
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| 17th Jan 2008 6:19 pm |
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wolster
Member Since: 07 Dec 2007
Location: various
Posts: 352
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I'm sure we'll be told otherwise by someone who knows more than I about such things.
BUT
I think an engine is most efficient at the peak of its torque curve and less efficient either side of it. Perhaps your RPM at 75mph is higher up the curve in 5th than it is in 6th?
Discuss .......... What if the "Hokey Cokey" really is what it's all about?
'54 TDV6 Auto SE, Silver, Leather, HSE Wheels, Alpine Roof, Light Guards, Black Side Tubes, Tints.
Y 110 County Commercial, White, just bought it... watch this space for added bits!
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| 17th Jan 2008 8:49 pm |
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Slimer
Site Moderator
Member Since: 06 Jan 2005
Location: Last Exit to Nowhere
Posts: 16295
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I'd have to agree with that, not sure exactly where peak torque is but definitely keep the revs above 2000 rpm, I'm normally only just going into 5th at about 65-70mph, can't remember the last time I used 6th. Over 5k now on my new D3, never dropped below 30mpg The End
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| 17th Jan 2008 9:16 pm |
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craig
Member Since: 08 Aug 2006
Location: Home of LR.
Posts: 2545
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I presume theres a difference with a tuned engine, Slimer?
Any idea where the peak torque is on a tuned engine?
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| 17th Jan 2008 9:23 pm |
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Slimer
Site Moderator
Member Since: 06 Jan 2005
Location: Last Exit to Nowhere
Posts: 16295
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Presumably Craig though I don't know what the difference is, presuambly TFC can help out with that - especially with regards to TT
I drive my current untuned D3 the same as my previous JE tuned D3 and get slightly better consumption on the new one which is encouraging as the old one got better as the mileage increased. New one does have the slightly revised LR engine set-up that they introduced with the 07MY though The End
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| 17th Jan 2008 9:32 pm |
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craig
Member Since: 08 Aug 2006
Location: Home of LR.
Posts: 2545
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Cheers Simon
Have to admit, i do leave mine in 6th, as it seems to go against the grain having the engine revving and working harder than it needs to.
I'll have a chat with 10, when we hook up to do my roof lights - as well as a few other things 
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| 17th Jan 2008 10:19 pm |
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simonsi
Member Since: 14 Oct 2007
Location: Auckland
Posts: 1264
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NHR wrote:Are the ditances and route taken on each part of the trip really identical? Over 150 miles the effect of one way streets, diverging carriageways, etc may cause a difference.
Furthest apart the two routes get is either side of a dual carriageway/motorway or across an M-way junction roundabout.... Cheers
Simon
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| 17th Jan 2008 10:28 pm |
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simonsi
Member Since: 14 Oct 2007
Location: Auckland
Posts: 1264
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wolster wrote: Prevailing wind in UK is from the SW.
5mph wind pushing you home and slowing you there may have an effect?
Just a thought
All of engine effort doesn't go into fighting wind resistance but a lot does. Especially the faster you go. Travelling at 70mph could conceivably be equivalant to 73mph into a 5mph wind and 67mph with a following one.
After difference in fuel this is my favourite (could be both of course), to prove it I guess I´d have to try the return trip all on Loughborough diesel.... Cheers
Simon
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| 17th Jan 2008 10:31 pm |
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Slimer
Site Moderator
Member Since: 06 Jan 2005
Location: Last Exit to Nowhere
Posts: 16295
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Try it for a while Craig, I know Stu did and got some improvement, change up at about 2600-2700 rpm and keep the revs above 2100ish, use cruise control whenever you're on a long run The End
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| 17th Jan 2008 10:32 pm |
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craig
Member Since: 08 Aug 2006
Location: Home of LR.
Posts: 2545
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Cheers will do.
Plenty of mileage to do over the next couple of days - so will give it a shot
See you Saturday
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| 17th Jan 2008 11:27 pm |
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