Winter/Summer Fuel Economy

Status
Not open for further replies.
Joined
Sep 23, 2018
Messages
861
Location
Maryland
Just curious how much change in fuel economy people are observing between winter and summer months. I've got a 2.5L Mazda Skyactive engine that gets 36-38 MPG in the summer. Now that temps are hovering around the freezing point, the economy has dropped to 31-32 MPG. That's a 15% reduction due to longer warm-ups, denser cold air and winter-formulated gasoline (which has lower energy per unit). Our summers are usually in mid to high 80's and winters are right around the freezing point.

What are other folks getting? What kind of engine and what are the temperatures like in your area?


Ray
 
Last edited:
I have gone from 9.8L/100km to 11L/100km (24mpg - 21mpg) so far from the summer until now in the Caravan. 3.6L V6, mostly highway driving with some traffic. I would says 70/30 split.

It's about 28-32F here right now depending on the day.
 
Last edited:
I lose about 1 to 1.5 mpg with my F150 on winter fuel. Summer milage is 14.0 mpg Winter is 12.5 to 13.0. 4.6 liter engine on that vehicle. My Versa not goes from 38.2 down to 33.6 mpg between summer and winter gas. I use e10 in both. Using e0 doesn't help increase the milage at all.
 
Originally Posted by RayCJ
Just curious how much change in fuel economy people are observing between winter and summer months. I've got a 2.5L Mazda Skyactive engine that gets 36-38 MPG in the summer. Now that temps are hovering around the freezing point, the economy has dropped to 31-32 MPG. That's a 15% reduction due to longer warm-ups, denser cold air and winter-formulated gasoline (which has lower energy per unit). Our summers are usually in mid to high 80's and winters are right around the freezing point.

What are other folks getting? What kind of engine and what are the temperatures like in your area?


Ray



I have noticed this with every vehicle I've owned. Winter fuel economy is never as good as summer.

Btw, I have the same 2.5 SkyActiv engine. We average about 31 but in recent weeks the mileage is closer to 28. That is normal in my opinion.
 
The denser ambient air from dropping around 40-60 deg F between summer to winter is responsible for an additional 10-15% of wind resistance on the vehicle. That's probably the largest factor in mpg. If you run or bike outdoors all year round, you know the effects.
 
The biggest impact for me is from running the OE LRR tires to winter tires. As soon as I put them on my consumption increased at least 0.3g/100mi.
 
Originally Posted by 69GTX
The denser ambient air from dropping around 40-60 deg F between summer to winter is responsible for an additional 10-15% of wind resistance on the vehicle. That's probably the largest factor in mpg. ...
Some additional reasons:
Tire pressure drops if you don't compensate by adding air;
Even if you do restore pressure, tires have greater hysteresis losses;
Lubricants are at higher viscosity;
Energy expended warming up the engine;
Rich fuel mixture longer when cold, longer fast idle;
Longer warm-ups to cope with windshield frost, etc.;
Snow
 
I seem to be losing more fuel economy on newer cars in the winter than on my older cars.
Sure, the newer cars are getting better fuel economy in the summer & winter than the older car however, the drop is greater in my newer cars by comparison.
 
Newer cars have trouble staying with the thermostat full open in winter at full temp, this is due to the car's engine being more efficient and because the modern cars drag is lower so the engine doesn't work as hard and make as much heat.

Emissions requirements drive a pig rich rich condition in the tune to get the cat to fire off, there are specific parameters and time durations to accomplish this.
Personally I think it foolish this is done, for those who run short trips it destroys fuel economy more than the cat.

A tuner package like HP tuners can with time, patience, a laptop and logging scan undue the pig rich condition, reduce duration and likely add timing into cold conditions but the software is too expensive to justify normally for a few winter mpgs.

One thing I have noticed is that a manual transmission car, even a modern one can get almost the same MPGs even on short winter trips by driving a little different, i hock it up to the driver being able to outsmart the ecu and the transmission fluid thickness

Ah well, this has been one of my major complaints that most companies don't care about winter fuel economy and design poorly for winter
 
Last edited:
Well, it's reassuring to see others getting about the same decrease as my car. In another few weeks, average temps here will drop a bit more. We may get a period of a couple weeks where the temps dip even more into the 10-15 F range. Anyhow, I was quite pleased with this new car's summer economy and was a bit surprised that it dropped as much as it did in colder temps. My Tacoma truck also loses about 15% in the winter but, it's a 2011. I thought the Mazda (a 2018 model vehicle) would do just a little bit better.

As for air density, if memory serves, for every 10 degrees (Fahrenheit) drop, density increase approximately 5%.

... Perhaps the real point I'm making, is that it's not officially winter yet -and I'm already wishing it was spring!

Ray
 
In my DD Versa, I get 37-39 in the summer. Winter I'm getting 32-34. Also have to factor some more idle time to the formula.
 
Originally Posted by RayCJ
Just curious how much change in fuel economy people are observing between winter and summer months. I've got a 2.5L Mazda Skyactive engine that gets 36-38 MPG in the summer. Now that temps are hovering around the freezing point, the economy has dropped to 31-32 MPG. That's a 15% reduction due to longer warm-ups, denser cold air and winter-formulated gasoline (which has lower energy per unit). Our summers are usually in mid to high 80's and winters are right around the freezing point.

What are other folks getting? What kind of engine and what are the temperatures like in your area?


Ray


Around here , winter MPG is higher due to the A/C is not running ( except a little on defrost ) .

2015 Chevy Sonic 1.8l automatic .city 24 - 26 MPG , highway 30 - 35 MPG . 75 MPG highway .
 
Mine goes down from 15-16 city to 12-13. I mainly do short trips so the 4Runner doesn't get warmed up and I do more idling with the heat on (waiting to pick up kids, ect). Last winter I was using 0w-40 M1 and this year I have PYB 5w-30 and the mileage is similar.
 
Originally Posted by sw99
In my DD Versa, I get 37-39 in the summer. Winter I'm getting 32-34. Also have to factor some more idle time to the formula.


In my Altima(combine mpg), I'm in the low 30s mpg in the summer. In the winter, I'm in the low 20s mpg.
 
I always thought that 50-60 deg f was temperature that results in best mpg. Its halfway between -20 F and 120 F, so the sweet spot.
 
Is there a formula for figuring idle time into mpg. I'd say this is where most of my loss is coming from. My computer is only showing a few tenths lower so far, I imagine it will get worse when winter actually hits, it's still fall you know.
 
Last edited:
Status
Not open for further replies.
Back
Top