Winter cold killing everyone's MPG?

[Natalya]

All right, drove to work with the 2010, didn't see much improvement, only about +3°C. I think I need to block off the stock air intake path into the engine bay and rig the end of the dryer hose a little closer to the catalytic converter and maybe block off other airflow into the engine bay from other spots.

*EDIT*
Blocked the air intake path with some aluminum tape, looked at lower grill block situation, looks like black foam is the way to go down there.

[MetroMPG]

I'll see your nice-looking WAI and raise you one ghetto WAI:



Yes, those are tin cans with sheet metal screws and a coat hanger on the end of the intake. Oh yes, and duct tape. Winter beater Metro!

Despite this and a 100% grille block, I only managed 52 mpg US / 4.5 L/100 km on my last tank.

Needs a coolant heater. I need to start a fuel log, too.

[stefanv]

I was averaging about 5L/100km (47mpg US) towards the end of the summer after a few months of eco-modding/driving. As the weather got colder, this got worse. Over the past 90 days, I've averaged about 5.6L/100km (42mpg). The worst tank was 6.1K/100km (39mpg) when it was really cold here (-20 to -10C).

I console myself with the fact that last year over the same time period, I was averaging 6.5/100km (36mpg).

[MetroMPG]

Its impressive when your winter economy improves from year to year, especially given the cold we've had this year.

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My parents' 2005 Camry, 2.4L 4-cylinder: 11 L/100 km on the last tank, mostly lots of short trips, local driving. That's 21 MPG US. Wow - the city EPA rating is 21 MPG! I would have thought it was doing much worse than EPA.

[vortex]

In addition to all the temperature dependent factors of efficiency and seasonal fuel blends, a large factor is simple air density increase. Aerodynamic drag force (F) = 1/2 Cd * rho * V^2 * Aref . With all other vehicle factors unchanged the variable from summer to winter is air density rho. At 70F and 50% RH air density is 0.07373 lb/ft^3. At 20F and 30% RH air density is 0.0816 lb/ft^3. The density difference from summer to winter in this example is (0.0816-0.07373)/0.07373 = 10.7%. This is also the increase in aero drag force over that temperature swing. It is not unusual for Class 8 fleet operators to report a 10% fuel economy reduction from summer to winter.

[stefanv]

Yes, quite right about the air density. It looks like much of my 12% increase in fuel consumption from summer to winter can be attributed to increased air density.

[ByDesign]

It's a compound effect too. True, with higher air density aerodynamic losses are greater, but there are also greater throttling losses. Higher air density means you use slightly lower throttle position for the same power output, therefore you are restricting the air more which means the engine has to work harder for the air it gets. (Obviously this is most applicable at low throttle operation.)

I don't know the numbers, but it has to be smallish. It is, nevertheless, another contributor to cold weather reductions in fuel economy.

On the plus side, at WOT, the engine will actually produce a little more power for donuts in the snow when it's cold.

[Angel And The Wolf]

Originally Posted by Natalya

I'm throwing up like good numbers, but I'm driving an ecomodded G1 Insight. And I know I'd be doing better if it wasn't freezing.

Anyone else experiencing MPG drops because of this cold?

Anyone else considering installing a warm air intake? I did it on my old car, might have to do it to this one. I've already got a partial rad block and 100% lower grill block.

Due to Emission control laws, the Catalytic converter must be up to operating temperature as soon as possible upon starting. That's why your hybrid runs it's ICE for several minutes, even when your traction battery is fully charged. While driving, the ICE will cycle on as needed to re-heat your cat. A grill block will help keep the winter wind out from under your hood, but if the cat is exposed to the under car air stream, it will cool faster in cold weather. Insulating the cat should help keep it hot and your ICE off more. Of course, you could hack your temperature sensor to the cat, or maybe, lay it on a hot ICE part, but that would be illegal.

[redpoint5]

Originally Posted by slowmover

Build a garage. When cars were new that’s what men did before a car was bought. They had the right order in that.

People get many things out of order these days. That is to say, disorder is more common/accepted than ever.

+1 on garage. It's the proper place for a vehicle. All the junk should be given away, stored in an attic, or put in bins and stored near the ceiling of the garage. My neighbors have a 2 car garage, 4 cars, and zero cars in the garage. The cul-de-sac is clogged with their vehicles. On street view you can glimpse the open door which barely contains the floor to ceiling crap.

https://www.google.com/maps/@45.6895.../data=!3m1!1e3

I've got the Acura in the driveway in the same view, but that's because the 2 car garage already has 2 cars, a motorcycle, a 4'x8' trailer, a ping pong table, a futon, 5 bicycles, tools, etc inside. I've got 2 roommates and a wife to accommodate there.

Originally Posted by Natalya

Warm Air Intake on the 2010 Insight. I haven't tried it out yet but her ScanGauge was seeing 8°C or so when it's been about -2°C outside.

And I did the same for my 2000 Insight, although this only does half the airflow. The 2000 Insight has two air intake ports, one from the resonator on the left there and one where this vent is attached that goes directly to the outside down by the front bumper. I'm seeing IAT temperatures about 6°C higher than before, reading 17°C or 18°C on my OBDIIC&C gauge now instead of 12°C or so that I'd seen before.

Neat to see your mod.

If I recall correctly, the Insight is capable of running lean-burn until a certain intake temp is reached. Do you plan to remove the WAI in the summer, or do you not anticipate this being an issue?

[ECONORAM]

We've had single digit days, and days in the teens. It does help if I plug in the block heater for an hour prior to leaving. I also installed an engine bay cover like Frank Lee spoke of a few years back. BUT, I'm still taking a triple hit because of: 1) the cold, 2) had to put the clutch fan back in 'cuz the E-fan was eating 80amp relays, and 3) with the clutch fan, I can't use my custom WAI setup. sigh.