Cold weather = bad gas mileage?

[niterydr]

Originally Posted by NOT THE BLUE LAMPSHADE

I thought I was going nuts out here at WyoTech. I get about 20% less fuel economy in this cold out here!! And I'm at like ~7500ft. about too if that matters with gas consumption.

More air(denser and lower elevation and cold) = more fuel to get A/R
Less Air and Less Dense+Freezing Air = opposite?

I dunno.

Air and fuel molecules need to find matching dancing partners. If you have 1470 air molecules and 100 fuel molecules, then you have a 14.7:1 afr.

If you have a more dense air charge, aka 2940 air molecules, you need 200 fuel molecules to get that 14.7:1 ratio.
Make sence?
Colder air is more dense=more air molecules.
Its why inefficent turbo setups can "overboost" in cold weather and heat soak/have boost fade in hot summer months, they are getting more air molecules and are at an advantage on the compressor side of things and that carries thru the system to the engine. Most of the time engine bay temperatures balance out after the car is up to operating temperatures, but a car WILL make more boost @ 0 degrees versus 100 degee intake air temperatures if the system isn't setup/tuned properly to avoid that.

[Andrew7dg]

Originally Posted by niterydr

Air and fuel molecules need to find matching dancing partners. If you have 1470 air molecules and 100 fuel molecules, then you have a 14.7:1 afr.

and BOOM!!


Had a question about heat coming into the car from the heater. It seems like my car is always kind of cold. It doesn't get truly warm until it is on the highway. I mean I get heat out of the car pretty soon but not hot temperature like it is on the highway. I removed the A/C condenser because of weight and that opened up the radiator for more cooling. Did that have anything to do with it? Do I have a bad thermostat or is the engine running that cool when around town? Coming off the highway it stays warm.
Fluid level is good also.

[niterydr]

Originally Posted by Andrew7dg

and BOOM!!


Had a question about heat coming into the car from the heater. It seems like my car is always kind of cold. It doesn't get truly warm until it is on the highway. I mean I get heat out of the car pretty soon but not hot temperature like it is on the highway. I removed the A/C condenser because of weight and that opened up the radiator for more cooling. Did that have anything to do with it? Do I have a bad thermostat or is the engine running that cool when around town? Coming off the highway it stays warm.
Fluid level is good also.

Check your coolant temps via logger. You should still get to operating temperatures, but you could have a failing t-stat.