hey how does winter effect mpg?

[marcink99]

i did use my car in a week and now when i drive it i get worst mpg:( I always take fuel from the same bp premium station

[akordboy]

It's because of winter gas.

Click Here for Summer Gas vs Winter Gas

[yung turbo]

well if you have a turbo then atleast you get more power.

[vtracer20]

winter gas, + alot more warming up by the car causes mpg to go down

[fromGMCtoAUDI]

Warming up the car wastes alot of fuel. Many people still don't know that when the rpms drop to normal idle level you're good to go.

[elwigglero]

Warming up the car wastes alot of fuel. Many people still don't know that when the rpms drop to normal idle level you're good to go.

Well...You shouldn't ever take the car above 3k rpm or 50% throttle until the oil is at operating temp. For some reason, the b7's don't have an oil temp gauge, so you just have to wait 15 minutes or so.

[airbornerifleman]

A cold engine is less efficient than an engine running at normal operating temp.

Do you guys wait till the rpm goes down from 1500 to 800 before you drive off? Should you?

[08 B7]

yea u should defintly warm your car up before takin off...all your monitors are off when the engine is cold so it bypasses all the emission standards and spit gas wen u drive..its also better for your car if you plan on keeping it..

[NorcalPB]

It actually says in the manual that as soon as you turn on the engine you should start driving, anyone know why it would say that?

[Dangler]

It actually says in the manual that as soon as you turn on the engine you should start driving, anyone know why it would say that?

so all the fluids reach operating temps at around the same time.

For instance, if you warm up your engine first, your engine oil may be at operating temps, but your trans fluid is still cold. so you have an engine running at optimal levels while your trans is still catching up, possibly creating extra wear and tear on your trans.

so if you drive off right away, and take it easy for the first 15 mins, you'll put less stress on the surround components.

this is what i was told.

[minameismud]

i may let my engine sit idle for a few minutes...usually till i can feel my fingers again, then take off. i'll keep it below 2k with very easy driving until that temp gauge moves a bit and i start getting heat out of the vents, then it's pedal-down.

[airbornerifleman]

so all the fluids reach operating temps at around the same time.

For instance, if you warm up your engine first, your engine oil may be at operating temps, but your trans fluid is still cold. so you have an engine running at optimal levels while your trans is still catching up, possibly creating extra wear and tear on your trans.

so if you drive off right away, and take it easy for the first 15 mins, you'll put less stress on the surround components.

this is what i was told.

Do you wait till the RPM goes down, or do you drive off right away? 99% of the time I will wait until the rpm goes down to normal idle, which is a contradiction to which the manual says "drive off after starting engine". WTF?

[Dangler]

Do you wait till the RPM goes down, or do you drive off right away? 99% of the time I will wait until the rpm goes down to normal idle, which is a contradiction to which the manual says "drive off after starting engine". WTF?

yeah i pull away immediately after i start the car, because the idle speed will drop to normal levels quicker if you drive off vs. sitting and waiting. Typically on a cold start, your idle will be around 1200rpm, i assume this is to circulate the fluids quicker. then drops to around 800rpm.

i take off right away, and by the second block from my house when i reach the stop sign the idle is down to 800rpm.

[EMAXX]

so all the fluids reach operating temps at around the same time.

For instance, if you warm up your engine first, your engine oil may be at operating temps, but your trans fluid is still cold. so you have an engine running at optimal levels while your trans is still catching up, possibly creating extra wear and tear on your trans.

so if you drive off right away, and take it easy for the first 15 mins, you'll put less stress on the surround components.

this is what i was told.

That is correct. You don't want to let the engine idle for more than maybe a min depending on how cold it is.

If you let a performance engine idle, it's just bad all around.
Just take it easy until the car is all warmed up, driving at below 3k RPM's. Then once the car is all warmed up, make sure to drive about 3k RPM for a little bit to get everything moving well. Then just cool down the motor and take it easy for the last 1 min or so of driving.

[marcink99]

ok so this is the thing when i get fuel it used show on that litle monitor that i can get 465 miles or so i dont remember exact number but now after filling it says only 350 or so. Is anybody else expecting this?

[Buttafuoco]

The primary reason is that it's more difficult to vaporize fuel when the engine is cold, so your ECU compensates by dumping more fuel. Obviously, it takes longer for your engine to reach operating temp as it gets colder.

Also, the air becomes more dense as temperature drops...so the mass/air ratio increases and the ECU has to provide more fuel.

[BriAnders]

ok so this is the thing when i get fuel it used show on that litle monitor that i can get 465 miles or so i dont remember exact number but now after filling it says only 350 or so. Is anybody else expecting this?

i just filled up today and my mileage says 505/510 before i run out. so sorry, i cant say i'm having the same problem.



now directing this second response to some others in thread...

from the mpg perspective, it also makes sense to start driving as soon as you turn over the ignition. if you're just sitting there waiting for the car to warm up in the driveway you're going to lose mpg because the car is on but yet it hasn't even moved an inch. if i go 80 on the highway in 3rd gear i'll still have a better mpg than you because you're just sitting still in your driveway waiting for your hands to warm up with a whopping 0.0 mpg.

[Louis J.]

The primary reason is that it's more difficult to vaporize fuel when the engine is cold, so your ECU compensates by dumping more fuel. Obviously, it takes longer for your engine to reach operating temp as it gets colder.

Also, the air becomes more dense as temperature drops...so the mass/air ratio increases and the ECU has to provide more fuel.

Interesting info.