Why is mpg worse in winter

forgotmyname

Deleted_User wrote:

I've just got 340 miles out of a 50 litre tank from brim to empty. Last time I brimmed the tank in the summer I got nearer 400 miles. But it could just be my driving.

harveybobbles_ wrote:

Biggest killer is stuff like heated rear windows and heated seats.

Were you wearing a baseball cap backwards at the time?:rotfl:


What about the heated front screen? Approx 60 AMPs...

Mine switches on if its 4 degrees or below even if the screen is clear. Are drivers that lazy/stupid to know when to switch the screen on and off?

supermanjo

I never knew heated seats sucked up so much? I installed them myself on one of my Volvo's. The thing is only a few small pads with a tiny wire to connect it to! Lol!

atrixblue.-MFR-.

Weird_Nev wrote: »

They change the fuel mix to a "winter mix" too - particularly in diesels to stop it waxing in the cold. This mix is less calorific and so returns worse Mpg.

this is why i recommend in changing the paper style fuel filters and timing it right, each year.

start at winter where the fuel is mix altered.

so weather man says first time this year temp will hit zero, you have it changed, every year or at your manufacturers soec interval plus winter interval to aid propper fuel delivery, prevent clogging of the filter and poor cold starts.

diesels are ampage suckers in winter and return poor MPG if not serviced properly. glow plug heaters, internal heaters and demisters, with the added bonus of everything being regulated by air flow and air temp sensors water temp sensors this is why antifreeze mix should also be spot on also colder the water then longer then engine takes to warm up if that water is not farr off the air temp due to impopper antifreeze mix ads more strain to the engine because of ice particles.

almillar

Good stuff above. You're right about colder, denser air, but in your microlite, at altitude, the air gets less dense, so you're engine is running less efficiently already.
Using electric for heat uses loads of electric. Just like your toaster, kettle, electric heater, hob, your heated seats and heated rear windscreen will put additional strain on your alternator, which will require more power from the engine. Try sitting at idle and switching on the rear heated windscreen and see if you can hear the engine note change. The heat from the blower is different - the heat for this is taken from the engine (and is a waste product really) so is really efficient in internal combustion engines. Using an electric car in the winter will feel different.
Anyway, I'm surprised no-one mentioned chokes. Anyone remember chokes? Well cars don't have them anymore, because the ECU does the same job automatically. That job is running the engine rich (more fuel) to get it started and keep it running when cold, then gradually leaning it out. Much better than us at managing the process than us, because it doesn't forget to turn the choke off. Combine that with the fact that you're taking heat away from the engine to warm yourself with, and you'll realise that taking longer to warm up does have a significant effect on MPG in winter. This will be felt even more for people who make short journeys, because they'll be spending less time at operating temp than people who do long journeys.

AlexisV

On the plus side, you should have slightly more power in winter because the air is denser.

Mark_Hewitt

supermanjo wrote: »

I never knew heated seats sucked up so much? I installed them myself on one of my Volvo's. The thing is only a few small pads with a tiny wire to connect it to! Lol!

Heated seats take extra fuel even when they are not operational as they are significantly heavier than standard seats.

celtus

The only good thing about winter driving is your engine will produce more power than in the summer due to cooler air having greatly density at cold temperatures

dacouch

vikingaero wrote: »

A bit like scratching our balls - it feels nice and we can.

As others have mentioned: cold starts, use of lights/heaters/rear window demist, changes in fuels. But also if it's raining you'll generally get a lower mpg due to the increased drag from the water on the road (there is a fine line between the presence of water which will decrease your rolling resistance and improve your mpg and that of rain which will harm your mpg).

Love it, what other random experiments have you done

Notmyrealname

dacouch wrote: »

Love it, what other random experiments have you done

When I did an economical driving course with a former employer that was run by the manufacturer of the lorries we were driving, the impact of driving in water filled ruts on motorways and through puddles could be as much as 10%.

If you don't think water can slow down your car, find a wide puddle a few inches deep and drive into it at 60MPH. You will notice the braking effect.

Strider590

Notmyrealname wrote: »

If you don't think water can slow down your car, find a wide puddle a few inches deep and drive into it at 60MPH. You will notice the braking effect.

It's true, but lets not tell people to try it....... Aquaplaning into an Oak tree is more braking effect than i'd care to experience