Fuel consumption, aircon on v off

Well I tried a few consumption tests today and I couldn't replicate hd3's figures at all.

At idle , 780rpm my Scanguage was telling me 0.21LPH (litres per hour) - it didn't matter what switches I pressed or knobs i twiddled I couldn't get it to move from 0.21 for more than a second until it returned to that figure. The revs changed to 800 or dropped to 765 when I switched on/off the AC - or moved the setting from feet to screen to demist - but in a split second the revs returned to 780 and the guage to 0.21.

On the way home, on an empty country road, I set the cruise control to 50mph and had Mrs Singvogel switch on and off the AC - guage didn't change from 5.27LPH which is as near as dammit 43mpg.

I must investigate further during the Xmas hols.

Singvogel.

.. and I couldn't replicate hd3's figures at all.

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mine's no doubt fibbing thru it's teeth ..
at one stage it displayed the equivalent of 51 mpg average .. 'n i know that's rubbish
mph do not line up with the hippo's speedo .. at 70 on the dial .. s.g. displays 65 ..
i've no idea yet which is right .. 'n that has me wondering about the odometer as well ..

maybe i should have chosen '1.9' for engine size .. as opposed to '2'
( and anyway .. in reality .. 'capacity' will change .. depending if an engine is turbocharged .. or not )

i also ask myself .. how does the s.g get the lph figure ?
does it guestimate it itself .. or does the engine ecu have the info and send it to the s.g.
and if so .. how does the ecu calculate it ..
i could see the ecu having that info If it has fuel-pressure + injector size / stroke + go pedal position + maf info + temps info + rpm ..

in any case i've yet to do the 'fillup routine' for the s.g. .. maybe that's a factor ..

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tbh: i aquired the s.g. mainly for mph info .. as i can't see the onboard speedo properly
due to my prefered steering wheel position ..
and knowing the alternator / battery voltage is handy
as is air intake temp ( wonder if it will show -5c if the sensor quits working )
and the m.a.p. reading to show alls well .. or not .. with the turbo and affiliated system

can figure out mpg easily enough .. and know fuel tank level .. without the s.g.

have read on the web. many stories .. good and bad .. about its fuel consumption display
and its general performance ..

though .. be nice If i could get it to display fuel consumption ( and mph ) accurately ..
as is .. i use tacho/gear selection to know my mph .. ..
and my physical senses to know how to use the go-pedal for decent mpg ..
and wether the ac or ptc is having an effect on power delivery / fuel consumption ..

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i'll do that 'fillup' routine .. maybe change some 'settings' .. and monitor the results
( maybe try and turn the synergy 'off' 'n see if that is reflected on the s.g. )

yes .. quite a big difference between my LPH readout at idle .. and yours

as of now .. i'm keeping the ptc device shut off .. and monitoring mpg at the fuel pump

I use all the instruments - Scanguage and the Freelanders originals as guides and indications rather than definitive factual information. Except for the SG's rpm and the intake temp. which I believe to be very accurate.

I've had a SG for a long time now and also use the 'fill-up' procedure - it needs of course always filling to the neck, but after a few times it started to predict the amount quite accurately - eg if it said it expected to get 49.5 litres then I was happy to see that I put in that amount to within a litre most times.

I've used it on several long journeys and it normally agrees with the figures I get myself when I use the sat-nav mileage which is more accurate than the odometer.

I've also calibrated the SG's MPH setting by sitting on the motorway at a steady 65 on the sat-nav and having Mrs S adjust the SG until it read exactly 65 too. The LR speedo was reading around 67/68. I also noticed that my 235/55 17 tyres made the speedo read nearer the true mph than the original 225/55 17s.

The 4 guages I normally have on the display are volts, air intake temp, coolant temp, and litres per hour.

After the initial week or so of 'playing' with things such as boost and power I settled down with the above 4.

Singvogel.

I reckon 65mph actual at 70mph indicated is about right for most speedos. Do the traffic police trick they are required to do at the start of every shift: drive on motorway or dual carriageway on which the marker posts are properly maintained (i.e. not run over by the tractor mower and just left there!) at whatever (constant) speed you choose, and get your passenger to observe how long it takes to drive past 16 marker posts (i.e. one statute mile).
48s = 75mph
50s = 72mph
53s = 68mph
57s = 63mph
60s = 60mph
etc etc...

Or you could try a satnav, which will be accurate provided the road is horizontal!

Absolutely right Ian - the original tyres gave a speedo reading of 69/70 when the actual speed according to the Sat-Nav was 65.

There is a dead straight, level road near me which the police for use for checks they have clearly marked off a mile using marker posts and painted symbols on the asphalt.

Very useful as I have tried it a couple of times, even using a stop-watch to double check.

Perhaps a I'm a bit over the top, splitting hairs with the accuracy thing, but I do a lot of long motorway and dual-carriageway journeys using the cruise-control and I want to be able to sit right on the legal maximum (where there is one) without having to worry about the polizei in unmarked cars.

Tip for visitors to Scotland - beware of unmarked cars on the A9 Perth to Inversneckie in particular.

Singvogel.

I've also calibrated the SG's MPH setting by sitting on the motorway at a steady 65 on the sat-nav and having Mrs S adjust the SG until it read exactly 65 too. The LR speedo was reading around 67/68.

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oh .. so mines 'normal' )) .. more or less .. good to know

I also noticed that my 235/55 17 tyres made the speedo read nearer the true mph than the original 225/55 17s.

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mmmmmm .. interesting .. ..
mine are the standard 225/55 17s

I reckon 65mph actual at 70mph indicated is about right for most speedos. Do the traffic police trick they are required to do at the start of every shift:

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cheers for the info .. i'll give that a try ..
i've no gps device .. although maybe there's an iphone app
( my iphone is as it left the factory .. yet to try adding apps and whatnot )
though .. it has a nifty stopwatch ..

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anyhowz .. just calculated my latest mpg for the previous 279 miles ..
it be 42mpg ..
and that's using the ac/demist often .. but ..
keeping ptc use to an absolute minimum .. or disabled altogether
( didn't record the mileage when i removed the in-cab ptc relay )

found a 'bp-ultimate' fuel pump that cuts off automaticaly at near-as-damn-it brim level
( though .. rekon i still prefer shell-v .. normaly end up with a bit of both in the tank )

At risk of going off topic, there is a lot of unmarked stuff on the four-lane section of the A1(M) near Peterborough, and used widely on the Beds/Herts stretch too. And my boss is a bloody JP!

( delete-post-edit ) maybe not the place for contentious observations re. driving

Someone plugged a scan thing into my hippo some years ago. Reading was way out. It must base the results on the info you put in (1.65ton, 2.5L with 6 cylinders and an auto gearbox) and info it acquires (raw current) data from the engine computer like rpm, engine effort (load) and temp. Putting this together gives a result based on what it knows, or at least generate data from it’s algorithms. In theory if you suddenly hit a headwind it should feel the revs drop and the load go up. That’s assuming it knows the result of changes like 20% increase in rpm means X more fool burnt if you stay in the same gear with no change in load. I think if it reads ok you then you’re lucky.

Running on 'auto-pilot' (cruise-control) my Scanguage certainly responds to up-hill and down-hill sections as the fuel reading goes up or down according to the load.

Can't comment on head-winds, but I'm going to take more notice in the future.

SV.

just to add a btw. note re the scangauge

found this ..
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text from a forum:

" The one small weakness of the Scanguages is with Chipped engines if the Chip changes the fuel rail pressures after the ECU and is open loop BUT the Scangauge will still be pretty damn close

The Scan gauage initially just uses a standard 3.0 Litre figure for injector flo rates and it works out fuel used by "standard fuel flow x how long the injectors are open". When you adjust the amount of fuel you add to the tank at your first fill that + or - which shows as a percentage in your adjustement is how much the Scanguage will recalculate with so it will now be "standard fuel flow/percentage correction x injector cycle".

IE if the vehicle takes 5% less fuel than predicted the Scanguage will now deduct 5% from the calculations of fuel flow and fuel used etc and from now on the AVG and LPH figures should be much more accurate. Another fill or two and you will not need to touch it again.

Resist the urge to change that % figure every fill... if the fill is within about 2 or 3 litres per 100 of what is expected those small differences will only have you chasing your tail. Only adjust it if the figures are out consistently one way IE always takes more fuel or always takes less. "

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well .. i've done the 'fillup callibration' routine ..
am still getting o.t.t. fuel figures .. e.g. LPH is now higher than it were before ..
estimated LPM be more in line with a petrol V6 methinks

yet my manual fillup / mpg calculations on trusted computer ..
sais i'm still getting 40+mpg ..

maybe it's the 'synergy' .. as i'm constantly on '10' ..
and don't have the in-cab switch hooked up ..
( yet to try the fuel readings on the scangauge with the synergy power switched 'off' )

never mind .. the other scan 'gauges' are useful ..

would be nice to be able to measure ground temp some meters ahead of the vehicle ..
yet to find a device that would do that .. i.e. within vehicle adaptability and ££ reason

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and regarding mpg ac/demist 'on' or 'off'
recently did 320 miles with it constantly 'on' ..
calculated mpg was 42 ..
( ptc heater gizmo disabled )

If the scanguage can be trusted, then the fill up re-cal will offset the synergy difference if there is one, if say the synergy were using 10% more fool. Hence after some average motoring (speed/style etc several times) and several fill up re-cals cycles it should be fairly good. The fill up re-cal should counter any offset.

Although I don't trust these systems as they should use "area under a graph" calculations over time with regular measuring intervals.