Which computer to believe?

I'm in a quandry, do I believe my trip computer or the Fuelly calculation for my fuel figures? In the car I use the auto trip average for each journey and for the vast majority of my journeys this shows trip average MPG's between 46 and 53mpg and sometimes better (not often!). Over 6 fuel-ups my Fuelly records indicate I'm getting only 39.5mpg average with a tank best of 41.7mpg which is crap considering the claims for the car. I generally fill up at the same forecourt and to the same level in the tank (I always fill up until I can see the diesel in the filler tube rather than to the first click of the trigger as often that is set off by foaming or high pressure from the pump.
So which to believe? I'm tending to feel that the trip computer is a con and is flattering the car's fuel economy.

Something else - I have the InControl remote app/ system on mine. It records all my trip distances/ speeds/ fuel consumption on a 3rd party server................. I wonder if Land Rover monitors the figures (which appear to be incorrect!)? Big Brother strikes again? How would I find out if LR is looking at my records and might hold them against me in the event of a claim that the car still is not as economical as claimed.

Fuelly should be accurate as you have entered the total "litres in" against the total "mileage out" which makes up the average over the complete life of the data. Unless of course you've entered incorrectly, also missing a fuel up will add a small amount of irregularity due to tank fill level at the start and stop of the data.

I keep a seperate spreasheet too, and this does show the Trip estimator while good, is usually a bit optimistic by an mpg or so, especially on the more "economical" runs.

Same here, my comparisons between Fuelly and trip computer indicates the trip computer to be anything between 5% and 10% on the 'optimistic' side.... Same thing with the range left calculations - when getting to the last 100km (~60 miles) the range drops a lot faster then the actual distance travelled.

So far it does look like the trip computer is on the optimistic side, when I take my first long road trip in about a week I'll take a closer look and see exactly how optimistic it is.

What does your Trip B MPG show Tim? Presumably you've not reset that one, so it should show your total stats?

I've never reset trip A or trip B, will look in the morning as it's a bit wet outside just now here!

if you have filled up, reset trip A.
Do your trip until empty and fill up again.
Then divide the amount of the second fill-up by the driven km's and thats the exact L/km.
Divide the opposite way for MPG.
For me that's the only right calculation.
If you do this 5 times you can calculate an average L/km or MPG.

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and if you calculate the cost per mile, you'll be ill !

The older model used to under calculate the mpg readings & could now be the case that LR have changed the software to improve the display mpg.

I've said it before, how on earth can 3 more gears in prove the mpg by around 15mpg

Doug, it might have 3 more gears but 2 or possibly 3 of the new ratios it hardly ever uses in day to day driving! 1st and 9th for sure, the third one is 2nd as I'm sure that mine pulls away in 2nd or 3rd , or it has the ability to skip out gears as you accelerate and I loose count! 1st is so low it is only for towing and offroad and 9th doesn't seem to engage until over 60mph and even then it doesn't like to hold it at 60mph if there is any sort of external load like a gradient or headwind. One thing I love about the 9 speeder is that S mode and paddles are almost redundant now. OK so the paddles are going to be useful to hold lower gears offroad, but the gearbox is so alert to throttle changes that in situations in my last car where I really HHAD to use the paddles or switch to sport mode, in the 9 speeder it only takes the gentlest squeeze on the loud pedal to make it drop 2,3 or even 4 ratios and it just gets up and flies. These days I use the paddles more to force upshifts than to make downshifts and I cannot recall having to use Sport mode yet! It si a huge improvement over the 6 speeder.

I was expecting to see upto a 6-7% improvement. Mainly from improved efficiency in the gearbox (maybe 3%) and improved gearing (maybe 3-4%)

If Tim, you've moved from 36 - 39.5 then that's a 10% improvement! and if your fuelly signature is old and you are getting 40+ then that's actually an amazing improvement for a gearbox change. E.g. 43mpg would be a 20% increase in efficiency!

Does it stay in 9th at 70ish mph happily Tim? If I have one glimmer of regret on the Manual, it's the top gear seems too short and is costing fuel due to higher revs than neccessary at higher speeds (but then I don't drive it loaded to the gunnels with stuff!).