What MPG are we getting in cold snaps?

[superatticman]

Hi All

We had that cold period before Xmas, now we're having another short blast.

Any alarming mpg figures to report?!

Am averaging 15.5 in my slow 6 mile stop and start crawl to work. Takes on average 45 minutes to give you an idea of the pace. Usually get around 20 in similar traffic of which is about right for this car.

Some diesel owners mind are reporting an even more drastic drop.

 

 

 

 

 

 

 

 

 

 

 

 

 

[Linas.P]

6 mile craw for 45 min is probably as bad as it gets in terms of traffic, I used to drive ~18 miles in 45-60 min and I considered that to be already very bad. I know GS250 is little bit worse on fuel than IS250 as it is larger and heavier car, but 15.5 is still very bad - I would expect the car should bottom out ~20. In my experience IS250 was doing average ~26MPG and very very worst tank I ever had was ~18MPG, but it was 200k miles car with I think maybe one of oxygen sensors being a bit lazy and running maybe a bit rich. I only ever do full tanks and check MPG brim-to-brim as instant mileage could be anywhere between 1 and 99, so that is the other thing... I may have seen lower MPG at points, but then a blast on motorway once in a while and it would end-up somewhere 20+. My RC200t was probably close to what you getting and thus I considered it being very bad on fuel, the same drive where in IS250 I was getting 22-24, in RC200t I was getting 16-18... and whereas my long term average on IS250 was 26-28, the RC was 18-20... but that was obviously because it had that trashy engine and large and wide wheels and was heavier car.

What is takeaway from that? Nothing really... cars consumes a lot of fuel in traffic and the worse it gets, the worse is the mileage... that is why I am saying more should be done to improve roads as that may have more benefit than BEVs... traffic jams themselves are very wasteful and produces a lot of pollution which could be avoided on free flowing street with same amount of cars. I would still check things like tyre pressures etc. because 15MPG is very low. 

[J Henderson]

I reckon I'm about 10-15% worse off. Which, I would mostly attribute to the engine & gearbox taking longer to warm up. Plus, more time being spent idling whilst I scrape windows and wait for them to demist.

I guess having a layer of hardened frost on the roof, bonnet etc is also affecting things.

Long-term average is 32-33MPG, but last couple of tankfuls have been in the high 20's. (Dashboard readings).

[JDM-Fiend]

Nothing alarming, but mine has definitely taken a hit.

I drive 80%-85% motorway and I'm at around 25mpg-27mpg average. Usually with mostly motorway I'll see 29mpg-31mpg.

Even after a full tank, resetting the trip and doing a steady 65-70mph for half an hour or so, I'll get about 26mpg-28mpg. Used to easily get 31-33.

I'm still interested to know what I get, but it's a fruitless task driving a V8!

[superatticman]

10 hours ago, J Henderson said:

I reckon I'm about 10-15% worse off. Which, I would mostly attribute to the engine & gearbox taking longer to warm up. Plus, more time being spent idling whilst I scrape windows and wait for them to demist.

I guess having a layer of hardened frost on the roof, bonnet etc is also affecting things.

Long-term average is 32-33MPG, but last couple of tankfuls have been in the high 20's. (Dashboard readings).

Yep...the engine is on for around 5 minutes before I even move an inch. Basically drinking fuel for the sake of it! Its also revving at about 1300rpm when it gets below freezing. This does settle down to around 800 when everything is warmed up though. 

Loads of stop start though in the heavy Greater London traffic. Can be periods of 1-2 minutes of stationary even. 

Get around 38-39 on a long run sticking to the speed limit. Tops is around 43mpg if cruising at 60. 

 

 

[Mr Vlad]

How often are your long runs Adam? What is a long run for you in your car? What was your car getting in mpg before the cold spell? 

[superatticman]

51 minutes ago, Mr Vlad said:

How often are your long runs Adam? What is a long run for you in your car? What was your car getting in mpg before the cold spell? 

Greater London to Skye. About 630 miles. About twice a year. 

Before cold weather got around 20 in very heavy Greater London traffic. 22-23 in what most people consider regular urban driving. 

At the end of the day you don't choose a big auto with a NA V6 if you are worried about economy. 

[Linas.P]

6 minutes ago, superatticman said:

Before cold weather got around 20 in very heavy Greater London traffic. 22-23 in what most people consider regular urban driving. 

Yes that would be my expectation and in experience that what I was getting in the past.

So 22-23... dropping to 20 in cold conditions as worst case scenario... but not 20 dropping to 15. I still think 15.5 is a bit low.

[Mr Vlad]

Well Adam I'd suggest either once a fortnight take your car for a 50 mile run with the occasional 'Italian tune'. To me you are strangling your car and probably coking it up. I also suggest you use E5, if you're not already, and I find adding a dose of Millers petrol ecomax helps a lot. I've  been using it in all my cars for decades. 

My journeys are short like yours but I take my is250 for a blast once a week to clear the cobwebs and its fun also lol. 

 

[superatticman]

54 minutes ago, Mr Vlad said:

Well Adam I'd suggest either once a fortnight take your car for a 50 mile run with the occasional 'Italian tune'. To me you are strangling your car and probably coking it up. I also suggest you use E5, if you're not already, and I find adding a dose of Millers petrol ecomax helps a lot. I've  been using it in all my cars for decades. 

My journeys are short like yours but I take my is250 for a blast once a week to clear the cobwebs and its fun also lol. 

 

Cheers. It does seem a little excessive, even with the constant stop start stop driving. Isn't E10 petrol known to cause slightly lower MPG? Tyres are all well inflated. Maybe worth looking at the tracking. 

Did have the dreaded Lexus dealer full £££ service and MOT recently. They should have picked up on anything that's badly out of kilter. 

Am driving up to Halifax this weekend. As you suggested...rather than drive like Granny all the time....lets unleash it where appropriate. Being mindful of the conditions of course. 

 

[McRattlehead]

I normally get about 53mpg but since the temp has been below zero for the last month  it's now 48.

Last year it dropped to 45mpg,since then i have returned to using E5 fuel which has improved consumption this year.

[Linas.P]

Yes E10 gives ~ 1% worse fuel economy compared to E5 and ~2% compared to 100% petrol. In theory is like 1.5-3%, it is kind of combination of slightly lower power and slightly lower MPG.

[Mr Vlad]

If you've recently had a service at Lexus then they'd have picked up on Anything not right. So basically your cars got a good bill of health. Stop start traffic is a killer on fuel economy and yes E10 makes mpg worse.

That'll be a very good drive to Halifax this weekend. Check weather conditions before you set off. I'm in Rochdale and we've still got snow/ice on untreated roads.

One thing I did on my way to Leeds was when on the motorway I put it in manual mode and left it in 4th all the way. Red lined it once just for the hell of it lol but was surprised that it didn't affect my mpg as much as I'd have thought. 70 mph was 4k revs I think so that gave the engine a good workout. Couldn't hear the engine, always have my music loud lol.

[Linas.P]

7 minutes ago, Mr Vlad said:

If you've recently had a service at Lexus then they'd have picked up on Anything not right.

Lexus service is good, but it isn't magic - so I would not count on them to pick-up everything. I have broken down 11 miles from Lexus dealer after the service, well not exactly broken down, just my A/C pump seized, but that is example of Lexus not checking everything. They work from checklist and they check what is in checklist, if something obviously very wrong then they may pick-up on that, but otherwise it could be easily missed.

[Mr Vlad]

True Linas but not all lexus service places are the same. Stockport check just about everything. 

[MartinH]

35.9 mpg this tank, 37.8 mpg previous, mostly on cruise on the M1 in low 70s mph, sometimes a little more. E5 fuel.

[superatticman]

2 hours ago, Linas.P said:

Lexus service is good, but it isn't magic - so I would not count on them to pick-up everything. I have broken down 11 miles from Lexus dealer after the service, well not exactly broken down, just my A/C pump seized, but that is example of Lexus not checking everything. They work from checklist and they check what is in checklist, if something obviously very wrong then they may pick-up on that, but otherwise it could be easily missed.

Like that heat shield which fell off about two weeks after the service and MOT....

[ALAW]

My 2.2 mile commute home this afternoon 22.3mpg. According to the link app.

[Toyoda]

I drive roughly 20 mile a day atm 50% motorway and 50% city traffic and the display gives 17-19  mpg. however on my 40 mile commute with 75% motorway I had 24 mpg and its all on 99 E5.

[Mr Vlad]

Blimey that's good going on a 4.6 litre V8 Andrej.

[Jgtcracer]

Usually get around 22-23mpg per tank but around 19mpg at the moment.  It’s pretty much all country roads, 10 miles each way. Ive attributed the drop to defrosting the car and the longer time it takes to warm up.

[Mincey]

Betsy's in the mid 40's at the moment. I'm sure it could be higher than that but there are Scheissewagens to be had on the A1 between Huntingdon and Peterborough.

[beyond the blue]

My ES is down from 46 to 43.2 at the moment but will probably go down to 42 before it improves again.

 

[superatticman]

Far milder temperatures recently have seen a fair increase in my MPG. 

Around town in heavy traffic inc periods of stationary 18-21mpg.

Taking it easy on a motorway run recently cruising at just above 60mph was getting around 45mpg. Pretty good for a standard 2.5 V6.

 

[Bluemarlin]

I've averaged around 31mpg over the last 18 months in mixed driving. Best is 40mpg cruising at 60-65mpg.

Thr first cold snap saw mpg reduce to around 24mpg, but that was in combination with a tankful of Sainsburys E10. Since switching back to Esso E5 (which is actually zero ethanol) mpg has increased back to 28-30mpg.