Member Since: 15 Aug 2011
Location: Derbyshire
Posts: 137
Mira research suggests 56 mph is the optimum for fuel economy - hence speed limiters on Trucks set at 56 mph / 90kph.
Real world mph depends on your driving style, everyone is different! With a manual box I would expect to get 20% improvement on an auto so early to mid 30's.
24th Aug 2011 7:31 pm
albal
Member Since: 31 Jul 2011
Location: Southampton
Posts: 592
By the way all Discoverys will be different on their empty indication. Just because Al got 10 miles past 0 with 3 litres to spare doesn't mean yours will go that far. There again the car manfs tend to put a safety margin in. I guess you can experiment safe enough with a jerry can in the car but a lot of systems don't run after they have been sucking in air, so probably a good idea to brush up on where the purging valves are in the fuel lines.
Probably teaching you to suck eggs here but.... Also it was mentioned that there were 3 main resistances, rolling resistance also includes engine resistance and being able to maintain an even engine load helps quite well. The smoother you drive the better will be your fuel economy, anticipating things as far in advance as possible makes for a more relaxed and comfortable journey as well as the rewards at the pump, tyre fitters and the less wear and tear on the brakes.
24th Aug 2011 8:29 pm
discocuzzy
Member Since: 02 Feb 2008
Location: surrey
Posts: 2752
I have a fuel card so have never checked "you cannot teach stupid people to do clever things"
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05 plate D3 HSE in Zermat- Gone
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10 Plate D4 HSE Stornaway Grey
24th Aug 2011 8:50 pm
DiscoDunc
Member Since: 08 May 2006
Location: Bristol
Posts: 16390
ah yes the worshipped fuel card.
As someone once said - the worse case of pain is to :
whip me, strip me and take away my fuel card !!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.
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D3 HSE MY06 - Re-Cycled Worldwide
24th Aug 2011 9:11 pm
scooby driver
Member Since: 02 Jan 2011
Location: London
Posts: 145
I have just done 2500 miles across France, Germany, Switerland and Italy average mpg on the computer 25mpg. Calculated against total fuel usage this is about spot on. I started off at about 70 miles per hour which was giving an average of 31 but got bored and set cruise control at just above 80 when on motorways which is definitely not good for overall consumption
Car was fully loaded, 4 bikes on back and roof box on
I wasnt that disappointed my Evo 8 averaged 20mpg on a similar length journey last year
25th Aug 2011 6:21 pm
Pedros
Member Since: 25 Jun 2011
Location: Cumbria
Posts: 454
Terminal velocity! You find a big enough cliff, or a friendly Chinook pilot.....
Estimated speed: 200mph. Assuming the tank is empty when you push (not drive) it over, MPG: 0.
I have estimated the speed on what a skydiver can achieve. The Disco would have more drag, but significantly more mass. Consequently it could be significantly more. Experimenting to find out could be costly though, even more costly than your local stealer.
28th Aug 2011 2:05 am
Antjp
Member Since: 09 Aug 2013
Location: Warringon
Posts: 346
Re: slow but thrifty
I can only command shift into 6th at 50mph then I put the cruise on. where as the auto goes in at 60mph providing I'm not accelerating. Ie knocking cruise on at 60 it will go straight in to 6th gear
4th Nov 2013 8:55 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Ninja thread revival skills.Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 29 May 2007
Location: Dundee, Scotland
Posts: 20732
Re: slow but thrifty
Antjp wrote:
I can only command shift into 6th at 50mph then I put the cruise on. where as the auto goes in at 60mph providing I'm not accelerating. Ie knocking cruise on at 60 it will go straight in to 6th gear
All 05MYs do that. Software was changed for 06MY to allow 6fh gear @ 40mph My D3 Build Thread
Member Since: 21 Dec 2007
Location: Norfolk
Posts: 198
If my memory serves me correctly, the optimum speed for all vehicles was 58.4mph, which is 1800 rpm.
Billy BNothing is foolproof as the ingenuity of fools is endless.
2012 Discovery 4 HSE Luxury
4th Nov 2013 12:36 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
I'd bet that you get a better mpg driving at 40 than you will at 58.4. It is true that you loose some efficiency at low speed but drag is a bit of a challenge for a D3 / D4.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 29 Sep 2006
Location: MIDLANDS
Posts: 8052
I'd have thought it was more to do with the lowest possible speed cleanly pulled in the highest gear.
Auto boxes on D3's I had often didn't 'lock out' into 6th gear at 55-60'ish yet would easily pull the speed so I used to manually shift it into 6th. Seemed to have a beneficial effect on my economy....
I always found that sub 70mph paid dividends exponential to that above 70.
If I sat it at 65mph (sat nav confirmed 'real' speed) over 30mpg was easily achievable, tip into 70's and it dropped below 30mpg and 80mph plus it plummeted
........With a manual box I would expect to get 20% improvement on an auto so early to mid 30's.
Not all drivers drive the same way...so assuming a manual is better is an assumption
An auto may deliver slightly worse figures - but insulates the D3/4 from rotten driving.
& ensure right gear at right timeBREXIT - done properly.
Right now ...We need Government - not Politics
Save the Dipstick Flagbearer-keep it simple, less likely to fail campaign-agenda items:Starting Handles, Acetylene Lamps.
Founder: Dipsticks-R-Us Inc
D3 HSE-perfectly formed, passenger friendly...has real DIPSTICK
Jag XK-but sadly no DIPSTICK...HUGE design fault
FL2 has DIPSTICK..."real comfort in rear seats"
VW Golf wondermobile (?)..has real DIPSTICK
Morris Minor..original DIPSTICK technology..and a real KEY.
.....Auto boxes on D3's I had often didn't 'lock out' into 6th gear at 55-60'ish yet would easily pull the speed so I used to manually shift it into 6th. Seemed to have a beneficial effect on my economy....
....agreed get up to warp speed then flick into cammand shift then into 6th..the mpg meter instantly returns a higher mpg.....
which makes me think there is an input from the transmission system that somehow informs said mpg meter & than it tells bigger lies
My tests with tank full to tank full & then using actual mileage say little if actiually no improvement
long journeys at cruise controlled speeds seem to work best for me if I sit between 70 & 80
......long inclines seem to cause havoc with all my tests....everytime I do this I seem to be going over M6 - Shap.BREXIT - done properly.
Right now ...We need Government - not Politics
Save the Dipstick Flagbearer-keep it simple, less likely to fail campaign-agenda items:Starting Handles, Acetylene Lamps.
Founder: Dipsticks-R-Us Inc
D3 HSE-perfectly formed, passenger friendly...has real DIPSTICK
Jag XK-but sadly no DIPSTICK...HUGE design fault
FL2 has DIPSTICK..."real comfort in rear seats"
VW Golf wondermobile (?)..has real DIPSTICK
Morris Minor..original DIPSTICK technology..and a real KEY.
4th Nov 2013 2:40 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
astonbuilder wrote:
I'd have thought it was more to do with the lowest possible speed cleanly pulled in the highest gear.
That's a rule of thumb that has stood the test of time reasonably well. As engines have become more efficient the minimum speed for peak mpg has reduced. If engines were 100% efficient (complete combustion, no waste heat etc) then the ideal speed would not be much above zero. At zero of course the mpg would be at its worst as you would not be moving, but with the perfect engine you would be burning zero fuel too. Oh and then stop-start was inflicted on us...Land Rover - Turning Drivers into Mechanics Since 1948
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on a similar length journey last year
