Member Since: 10 Apr 2006
Location: batemans bay
Posts: 1605
Less Fuel in Fifth
According to the "Scanguage" on a flat road
with the cruise control set on 100kph
my car uses between 1 and 1.5 L/HK less in fifth than it does in sixth
Probably a lot less when towing the vanPete
28th Dec 2008 5:35 am
simon
Member Since: 11 Jan 2005
Location: Shropshire
Posts: 18296
And how many revs are you doing in 5th and 6th at 100kph ?
Its not your speed its the amount of work the engine has to do to maintain the speed that determines fuel consumption. Your likely nearer 2K revs in 5th which is at the point where the engine is at its most efficient. At 62MPH (100kph) your revs in 6th are going to be too low efficiency wise in 6th gear.
28th Dec 2008 10:24 am
norto
Member Since: 10 Apr 2006
Location: batemans bay
Posts: 1605
Simon
It seems that the D3 is
happier at just under 2000rpmPete
28th Dec 2008 10:29 am
Neil Pettersen
Member Since: 23 Nov 2007
Location: Cutting the grass
Posts: 1254
What's the engine output reading and boost pressure ...... if it shows such.
28th Dec 2008 10:46 am
norto
Member Since: 10 Apr 2006
Location: batemans bay
Posts: 1605
My christmas present to me.
I havn't figured out all the codes yet
but there is plenty you can do with itPete
28th Dec 2008 10:49 am
Neil Pettersen
Member Since: 23 Nov 2007
Location: Cutting the grass
Posts: 1254
It would be interesting to see what your re-map output is giving.
28th Dec 2008 10:54 am
norto
Member Since: 10 Apr 2006
Location: batemans bay
Posts: 1605
Im too tight to floor it
because of the extra fuel ill use Pete
28th Dec 2008 10:59 am
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 73069
I was once told this by one of the resident wise old sages so did 100 miles in 6th, recorded the trip mpg then did the same trip back in 5th. Conditions (flatness etc) & traffic same both ways. Result was 10% lower mpg in 5th than 6th. Subject to the vaguaries of the LR Trip computer.
28th Dec 2008 11:43 am
simon
Member Since: 11 Jan 2005
Location: Shropshire
Posts: 18296
Nothing to do with a an old herb Del... LR state somewhere that their diesel engines are most efficient at 2,000 RPM.
28th Dec 2008 3:07 pm
simonsi
Member Since: 14 Oct 2007
Location: Auckland
Posts: 1264
TDV6 max torque is 1900rpm - that is where the engine is most efficient per engine revolutionCheers
Simon
28th Dec 2008 4:12 pm
Getafix
Member Since: 13 Sep 2007
Location: Melbourne
Posts: 229
steady 100 kms/hour on cruise, in auto 6th on a flatish section of road - drove for 40 kms. Got 7.7 litres per 100 kms with AT's on according to the trip computer. Not going to get better than that!<*(((<<
28th Dec 2008 10:40 pm
simon
Member Since: 11 Jan 2005
Location: Shropshire
Posts: 18296
simonsi wrote:
TDV6 max torque is 1900rpm - that is where the engine is most efficient per engine revolution
According to LR 2,000 revs is where its at. But who's to argue with 100 revs eh ?
28th Dec 2008 10:52 pm
simonsi
Member Since: 14 Oct 2007
Location: Auckland
Posts: 1264
simon wrote:
simonsi wrote:
TDV6 max torque is 1900rpm - that is where the engine is most efficient per engine revolution
According to LR 2,000 revs is where its at. But who's to argue with 100 revs eh ?
Really, I quoteth the LR website (follow the D3/engines/spec type route). AFAIK has always been 1900rpm:
The high-technology 2.7 litre TDV6 diesel provides:
• Smooth Torque distribution
• Flexibility
• Quiet refinement and economy thanks to the latest common rail technology (it meets EU4 emissions standards)
• Innovative materials
• Exceptionally high fuel pressure.
• 190hp
•Maximum Torque of 440Nm at just 1,900rpm."Cheers
Simon
28th Dec 2008 10:55 pm
simon
Member Since: 11 Jan 2005
Location: Shropshire
Posts: 18296
MAX torque yes... but I read LR stating that their diesel engines are most efficient at 2K revs... whatever 100 revs will make F all difference.
28th Dec 2008 10:59 pm
simonsi
Member Since: 14 Oct 2007
Location: Auckland
Posts: 1264
I think you are missing the point, max efficiency on any engine is at the max torque point, its where the output (torque) exceeds the friction and other losses in the engine.
Whatever you have read (link?) I guess is an approximation to the max torque point. Yes in any driving situation 100rpm is irrelevant but worth understanding the science behind it don't you think...then any reader can apply it to any engine Cheers
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?
100 revs will make F all difference.
