40.1Mpg - Am I Kidding Myself?

[Vintagesixtysix]

So the annual Devon trip happened a couple of weeks ago....and very pleasant it was too. The first major run of my 250 ownership.

I know the oil burning boys and girls get hot under the collar about their MPG's...I thought I'd ask for thoughts/ knowledge if the car is kidding me?

On the morning of departure I go to the garage fuel up....check the tyre pressure. I've done the fluid level checks a couple of days before....apart from a dash of pink coolant everything was in order.

Loaded Mrs V66's suitcase in with the aid of a forklift ( might be over exaggerating a bit...but only by a tad) my carrier bag, and a few basic groceries, and just two up we set off for the 254 mile trip. Nothing major to report ....M5 a couple of contra flows and a caravan accident past Exeter ( where manual start / stop was applied a couple of times).

Really enjoyed the run, my 250 has a rather dubious service history past...but still seems to be running smoothly...and the tank average is saying 40.1mph on arrival?

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[ColinBarber]

the trip computer always seems to read over, worth calculating the mpg yourself to see how far out it is.

[is200 Newbie]

V66 - I have had the same ... its always the case when using it on a motorway, cruise on and not belting it

Did you find the initial tank range was around 370 miles? When adding the remaining range to the trip computer at the end of the journey then you will probably find its showing its capable of around 450 to 500miles from the tank.

The most I have had reported from mine on the longest run I have done (340 miles) was around the 460 mark with if I can remember a quarter tank left so it will go past whats indicated on the "range"

Would be nice to hear from someone who has done a longer run to see what the actual mileage you can do from a full tank

[Derek870]

Pretty typical of a big engine I would say, pootling about town is the worst you can do, I filled up drove to Heathrow and back about 180 round trip and the tank mpg showed 42mpg

I set the cruise to 2000rpm, about 75ish, (god knows why I think I have OCD!) and got the 42

My normal 2 weekly average with a 22 mile round trip commute and pootling gives me 33mpg which I'm more than chuffed with

And I love my Lexus!!

BTW did I mention I love my lexus?

Lol

[finchy40]

I regularly do a similar run and average just over 40 each time. Keep speeds to around 70/75.

[Vintagesixtysix]

Yes Newbie...spot on...range said 370ish.

I was sat at 70 -75 on cruise control for some good periods....Saturday so helped with less commercial traffic on the road.

I will have to try noting a few fill ups and mileage to see how close the computer figures are. To be honest I'm not a big miler anymore....so not hugely bothered as long as I'm within the parameters you guys talk about....which I am, 34mpg is my everyday average on the car. I was impressed by this figure (40.1)and just wanted to get a view. If anyone does any decent runs soon would love to hear how far that mpg can be stretched.

V66

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[Mouser]

I tend to get 40-45 on a run, depending on whether I'm doing 65-70 or 70-75, best I've seen was 49.7 when I had a slight tailwind and a lot of roadworks with a 50 limit, and I'd filled up partway when the engine was already warm.

[Bingo123]

a bit offtopic but still asking:

i guess the meters are in miles cos i always fill full tank and do the trip A to 0 and see how much i got

i am mostly getting 350-370 miles in a tank or around 7 mile per litre.

am i correct in my assumptions

[dazed]

A reading of 40.1 mpg after a long run is quite normal, especially in the summer. It probably equates to around 37.5mpg in reality though as it always over reads by a few mpg.

I do about 25K miles a year, mostly on open roads with little town driving and I regularly have the computer reading over 40mpg for most of the summer - it tends to drop back to around 36mpg during the winter.

The best I ever had was 45mpg for a drive from Devon to Suffolk a few years ago. It was a hot and sunny day and the roads were generally free moving. That probably equated to about 42mpg in reality (about 580 miles for a tank!).

Basically, the IS250 auto loves cruising at a steady speed and if you avoid heavy acceleration and touching the brakes needlessly (i.e. anticipate the need to slow and just ease off the throttle) you'll be rewarded with impressive economy.

[normski2]

Basically, the IS250 auto loves cruising at a steady speed and if you avoid heavy acceleration and touching the brakes needlessly (i.e. anticipate the need to slow and just ease off the throttle) you'll be rewarded with impressive economy.

Agreed. Make use of that cruise control too. You can easily interrupt it if it gets a tad aggressive on an incline....and then reinstate on the level.

[Vintagesixtysix]

Yes Bingo 123 that's correct....or x by 4.546ish for old school mpg....

32 mpg on your figures.

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