<10mpg - wtf?

[turbo2256b]

I understand that, but what does what's in the rear end have to do with warming the engine up?

You can sit there and warm up the engine to operating temp and the gear lube is still cold. Untill the gear lube warms up your fuel economy still wont be that grate untill the lube warms up in the rear. There isnt the combustion heat the engine hass to warm it up. Once you put synthic lube in the rear you will find the vehicle will run like the engine is warmed up. Most of the drag on a cold engine is the rear gear lube. Same with a manual trans. Helps in and automatic too but not as noticeable.

[Mr. Land Yacht]

so, what makes a car get less gas mileage in the cold weather?
I know it's a combonation of factors...
so far what I'm seeing is oil is thicker so it causes a little drag on the motor...gear lube is thicker like the oil and causes drag in the drivetrain...
anything else?

[Nathan in MI]

You can sit there and warm up the engine to operating temp and the gear lube is still cold. Untill the gear lube warms up your fuel economy still wont be that grate untill the lube warms up in the rear. There isnt the combustion heat the engine hass to warm it up. Once you put synthic lube in the rear you will find the vehicle will run like the engine is warmed up. Most of the drag on a cold engine is the rear gear lube. Same with a manual trans. Helps in and automatic too but not as noticeable.

Ahhh, okay, gotcha.

[turbo2256b]

cooler air inlet temp drops economy some too. If you have an external air intake routing it to pull under hood air can improve economy in the winter.

[Nathan in MI]

cooler air inlet temp drops economy some too. If you have an external air intake routing it to pull under hood air can improve economy in the winter.

Yeah, I always pull my cold air intake off in the winter time. I figure it probably improves driveability somewhat too since the warmer air will allow the fuel to atomize more completely.

[Mr. Land Yacht]

why is it that cooler intake air drops economy?
causes issues with combustion maybe?

[Archangel]

One thing that affects warm up more than engine temp is rear gear lube. IF IT ISNT synthetiC it akes longer to warm it up than the engine. It is thick in the single didget range. You can pull the rear cover and it will just sit there.

Yeah... I don't even know what's in there... or even how much of it is left in there for that matter. Guess swapping it with synthetic fluid would be good, but it's sooo damn cold out there - does RTV form nice gaskets at like 10-15F?

[grandpaslincoln]

why is it that cooler intake air drops economy?
causes issues with combustion maybe?

Cold air is denser than hot air. The colder the air the more it condenses, so it can carry more fuel vapor which decreases economy.

[p71towny]

Couple more things that decrease MPG in cold weather
1. They put stuff in the gas to keep it from collecting water, it doesn't burn as nice as summer grade gas

2. Your tires might have a little lower of air pressure since the air is condensed.

3. Colder air is more dense, increasing wind resistance a bit, jets don't have to use as much throttle in colder temps to take off as in hot weather.

[Archangel]

Tires - 50psi in the morning after a cold night, halfway to Jackson (35 freeway miles) gauge read 52psi all around.

The other things do seem plausible tho... So really to up my fuel economy a little the only thing I can do is change my differential oil with some synthetic blend?

[Lincolnmania]

stop calculating fuel economy, just drive faster

my average driving up here the other night was 12.6 after the highway stuff, the last stretch at 25 mph on crap roads dropped it to 11.5. 15-16 mpg at 70, 6 at 25 mph per the tripminder.

[Archangel]

stop calculating fuel economy, just drive faster

Oh, I ain't the one calculating it, my bank does that for me And driving faster... 65 in a 35 fast enough for ya?

[seneeb]

just for an example, i know it's not 5.0, but it gives somewhat of an indication

i get about 16 in normal weekly commute in the aero. i drive it kinda hard and my average speed on 71 south from work to school is around triple digits

I get 28-32 running up and down the freeway on tuscaloosa runs (depends on what gas i get, bp seems to get me the best). set the cruise @ 70 and go

[OVERKILL]

My in-town average is about 13, highway is about 25. The diff fluid point is VERY valid, I remember the Mustang, the one winter I drove it, didn't have the "dragging" feeling that the TC has when its really cold out. But the 'stang had Mobil 1 in the ass-end, the TC has the stock gear lube. Time for a diff fluid change me thinks!

[Archangel]

Well, it ain't gonna snow this coming week, so I moved the sand bags from the Townie trunk to the Chevy bed - those are supposed to be 60lbs bags, but I bet that don't include all the water that was in there and that froze them solid. Also washed the air filter and replaced the vacuum line for the fuel pressure regulator. Car still needs washed, but I'm pretty sure that ain't gonna help the fuel economy, so I left it for some other time. Rear gear fluid will get changed ASAP, it's just a matter of weatehr conditions realy.