Member Since: 21 Mar 2014
Location: Co Carlow
Posts: 1958
Using Cruise Control & MPG
Well after several tests I can confirm that if I want to save fuel I can't use Cruise Control. Without Cruise Control I get an average of 27.7 MPG over 5000 KM, using Cruise Control this comes down to 25.3, again this test was over 5000KM.
Also run some limited tests with and without A/C and so far tests show about 1.5/2MPG loss when running A/C but considering the extra load the A/C puts on the engine I think this is about right.
This post is not a complaint about poor MPG as if I wanted to save fuel I would not have bought a Land Rover in the first place.Dale
Without it, and with good anticipation you will save c. 2 MPG - I do use it on long straight , level roads sometimes.
Can't comment on A/C though, but your numbers are what I would expect.
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tells porkies..
heres how to prove it...
get you D3 on a stretch of motorway say at 70 ish MPH (I assume your D3 is auto)
engage cruise...note the MPG
then flick gearshift left into command shift sport & forwards to engage 6th
the MPG reading will have grown by about 3 to 4 mpg's ???
which one is right when the engine revs & road speed haven't altered any.?
so what ever seniors or data from engine modules feed the mpg meter are skewed by the change to command shift
for me at least I dont rely on the mpg meter for anything other than novelty value...it's an in-between of an instant meter that yo-yo's up & down & means sods all & an averaging one that also displays something that isn't reality.BREXIT - done properly.
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28th Sep 2014 9:32 am
therealboss
Member Since: 21 Mar 2014
Location: Co Carlow
Posts: 1958
The measurements are taken from filling from brim to brim and using a calculator not using the readout on the dash, I know LR only put it there to make us feel better.Dale
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Re: The MPG gauge
BLFarrar wrote:
tells porkies..
heres how to prove it...
get you D3 on a stretch of motorway say at 70 ish MPH (I assume your D3 is auto)
engage cruise...note the MPG
then flick gearshift left into command shift sport & forwards to engage 6th
the MPG reading will have grown by about 3 to 4 mpg's ???
which one is right when the engine revs & road speed haven't altered any.?
so what ever seniors or data from engine modules feed the mpg meter are skewed by the change to command shift
Your reasoning is not correct and the displayed mpg is based on actual fuel flow (with arithmetic deduction for FBH use).
Land Rover - Turning Drivers into Mechanics Since 1948
...then why does the mpg swap readouts like I have stated above
how can the same speed & engine revs with no other variable active give a different reading...not arguing here but puzzled.
Is there actually a flow meter installed ?
that can read a minute flow (say five litres in 1/2 an hour) that is calibrated ?
I have cruised on motorways in command shift 6th with cruise engaged in the hope it gave me nmore mpg brim to brim & on checking didn't - the weather came pointed slightly to a different value
if there is it just isn't accurate..& of novelty value (I am referring to an olde worldy D3 one not a Super duper D4 one that may be different)
You put fuel in & the engine takes it out...its not as though its negotiable when you get to the fill up point pump you can get the lost mpg's back.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.
28th Sep 2014 10:43 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
BLF,
The actual mpg reading changes because the vehicle is genuinely using more fuel with cc engaged. This is reflected in the brim-to-brim calculation above because the vehicle is using more fuel with cruise engaged.
The fuel metering is very accurate and the D3 and D4 is capable of producing highly accurate mpg figures. For reasons known to themselves Land Rover has artificially made them over-read the calculated mpg. The amount of this artificial error varies over software loads / manufacturing years but the pure performance of the system remains good. In the D4 you can adjust the % over-read set in the CCF (typically set at +7% at the factory) so that it displays an accurate figure. As a result the accuracy of my D4 mpg display is within the resolution of the displayed digits. Fortuitously my D3 happened to be pretty -much bang-on, even if it made for depressing news at times.
As for 'no other variable' with engine speed and MPH there is a rather big one involved - the automatic gearbox and the mode it is in!
Land Rover - Turning Drivers into Mechanics Since 1948
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