Member Since: 12 Feb 2021
Location: London
Posts: 126
Ideal motorway cruise control speed for fuel efficiency
Says it in the title. Ideal cruise control soeed for fuel efficiency?
Yeah yeah, if you own a Disco4 you dont worry about fuel prices, but it is £170 to fill a full tank lately!!
16th Aug 2022 10:05 am
grzesiul
Member Since: 11 May 2008
Location: UK
Posts: 6266
55
16th Aug 2022 10:14 am
M3DPO
Member Since: 22 Sep 2010
Location: Notts.
Posts: 8074
Engine is most efficient at between 1400rpm and 1800rpm, switch cc off when going uphill, travel with the flow of HGVs is my advice It can when others can't,
It will when others won't,
It goes where others don't.
16th Aug 2022 10:21 am
grzesiul
Member Since: 11 May 2008
Location: UK
Posts: 6266
while works on M4 were in progress for a few years we noticed exceptional economy doing 50 on cruise but tbh on longer run 50 would make trip super long so we found 80ish is pretty ok averaging 32mpg measured between fills
G
16th Aug 2022 10:26 am
M3DPO
Member Since: 22 Sep 2010
Location: Notts.
Posts: 8074
You need to be travelling fast enough to get into top gear, 6 or 8 depending on model. These vehicles are reasonable economical on motorways, it’s short town driving where they drink fuel.It can when others can't,
It will when others won't,
It goes where others don't.
16th Aug 2022 10:33 am
Green Land Rover
Member Since: 21 Oct 2017
Location: Stourbridge
Posts: 408
On long journeys, I generally set the CC to 60. Nice compromise between fuel economy and relaxing drive.
Driving at high speeds just to save an hour of travel time isn't worth the feeling of being frazzled at the end of a journey for me. But then again, I'm an oldish git now 👴🏻 Discovery 4 HSE - Aintree Green
Freelander 2 TD4 SE Automatic - Tonga Green
Defender XS - Tonga Green - Gone Now
Freelander 1 Td4 ES Manual - Epsom Green - Gone Now
Freelander 1 Td4 Kalahari SE - Epsom Green - Gone Now
Freelander 1 XEi - Epsom Green - Gone Now
Member Since: 11 Sep 2016
Location: Marnoch
Posts: 4142
I tend to drive at an indicated 70mph on a longer run (so about 67-68mph) and get over 30mpg by doing that, a good compromise. of A roads I tend to do 55mph and that gets excellent mpg (currently above 35mpg actual! - indicated 39mpg on the lieometer)I want to see the sweets before I get into your windowless van... I'm not stupid!
Corris Grey D4 Commercial SE 2016
Zermatt Sliver 2007 D3 SE manual (gone)
Indus Silver D4 HSE 2015 (gone)
Bonatti Grey D3 HSE 2006 (gone)
White D3 S (LHD) 2007 (gone)
Firenze Red D4 HSE 2014 (gone)
Black RRS 3.6TDV8 2008 (gone)
Rusty Green Defender 110 1997 (gone)
Black FL2 HSE 2013 (gone)
16th Aug 2022 10:54 am
grzesiul
Member Since: 11 May 2008
Location: UK
Posts: 6266
haha me too but if you wanna reach 1200and a bit miles destination in sensible time or under one full day....
16th Aug 2022 10:56 am
rrhool
Member Since: 28 Aug 2014
Location: Norfolk
Posts: 4400
As slow as you can go in the highest gear possible! 55 or 60 was shown as a metric for 'extra urban' driving, only as a comparator, it's not the most efficient speed. If you could drive at 30 everywhere, in a high gear, you'd get best mpg.Richard
D3 SE 2007. Triumph 2.5Pi 1973. Ferguson TEA20 1948.
Discovery 2 4.0 ES 2001- Gone
Discovery 1 300Tdi ES '95 - Gone
Range Rover Classic '79 - Gone
16th Aug 2022 11:08 am
jimbo55
Member Since: 10 May 2022
Location: England
Posts: 38
I have found 60 seems to get me the best return on fuel consumption, on a recent 300mile journey with a tri axle trailer behind me I found I got a couple more mpg driving at 60 than I did when going at 50
Rrhool it isn’t as simple as going as slow as possible in as high a gear as possible, you need to keep the engine and gearbox operating in their most efficient points. For the engine this will be at around the peak torque speed (or maybe a just below by 100rpm or so) and for the transmission that will be somewhere when the torque converter is locked so isn’t using engine power to generate so much heat. In reality these points will be very similar, the transmission may be slightly more efficient at a bit higher speed but without the actual data for the disco driveline I can’t say exact values.
Driving in a high gear at 30mph will be significantly worse mpg than doing the same at 50-60mph based on the efficiency and also the fact that your road speed is very low.
16th Aug 2022 11:30 am
rrhool
Member Since: 28 Aug 2014
Location: Norfolk
Posts: 4400
Mines a manual gearbox. 5th is the straight through gear, 6th is a ratio. I do better at 70 in 5th, than 6th.Richard
D3 SE 2007. Triumph 2.5Pi 1973. Ferguson TEA20 1948.
Discovery 2 4.0 ES 2001- Gone
Discovery 1 300Tdi ES '95 - Gone
Range Rover Classic '79 - Gone
On a recent trip towing a 1800kg caravan to and from Cornwall I got quite different fuel consumption figures. Best was indicated 24 mpg on hottest day of year with windows often open, air conditioning on occasionally, and slow traffic to wait to pass accidents. Other bits of the journey showed higher fuel consumption on "easier" conditions. Self imposed 50mph maximum as part of the economy experiment.
Best explanation I can see is that BP fuel gives better return than ESSO.A vaccine does not stop you catching a virus, or passing it on, or getting ill from it, really ill. It does reduce the likelyhood of you dying when really, really ill. Stay Alive - KEEP AWAY FROM PEOPLE.
16th Aug 2022 12:27 pm
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 72778
60.
Slow enough to squeeze enough miles out of the fuel, fast enough so trucks aren’t piling up behind and I’m getting boxed in. Mpg would have been anything between 28 and 34, often temp dependant. Do the same in Skippy now and get a whisker under 60mpg.
All figures real mpg, not the flight of fantasy that is the trip comp.
16th Aug 2022 1:08 pm
lynalldiscovery
Member Since: 22 Dec 2009
Location: Maidstone
Posts: 7274
Mix it with the trucks and sooner or later you will be on the news!
I cannot stress this enough, only idiots run at the same speed as the trucks, these are the same idiots who drive on the inside of trucks on roundabouts and tight corners.
16th Aug 2022 4:50 pm
Captain Crosscheck
Member Since: 03 Sep 2021
Location: Oslo
Posts: 310
When I commute in my eGolf, 90 km/h is an ideal speed for getting a sensible amount of miles out of the battery. Same cruising speed as the trucks, and a lot of electric cars drive like that. However, when in the D3, I find 100 km/h being a more appropriate balance between fuel economy and keeping up with traffic.
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