Winter Fuel Mileage

[walkingchaos]

I just had a very long discussion on this with a good friend of mine who is far smarter then i am ( and spends a lot of time tuning modern cars ) and I know ive seen a couple guys post the same question and the same numbers i had, so heres what i learned.

Since they got rid of MTBE there really is no such thing as winter fuel anymore. They don't change the mix in winter anymore, its always going to be less then 10% ethanol. What changes is the air. Colder air is denser, we all know that when you get colder air into a car it makes more power (thus why we put expensive CAIs in) However the stock ECU in modern cars has one number in its little brain for the stoic ratio. It always wants to see the same air to fuel mix. So when the air gets colder and denser the ecu feeds more fuel in to match it. You get better power but your gas mileage goes to crap. I was seeing 29-30 from my P5 in the summer. Come winter i see 24-25. I thought it was too much and something had to be wrong but we recently had two days back to back here there were 60 degrees and my mileage went right back to 29mpg on the tank i used in that time. Clean your MAF, change your plugs, and make sure theres proper air in your tires and all you can do other then that is wait for it to get warm again (or get a stand alone fuel management system)

 

[Hank3]

I have seen my MPG drop by 1-2 since Nov/Dec during city driving. Will hopefully be back in the low 30's again soon

 

[Flash5]

I have seen my MPG drop by 1-2 since Nov/Dec during city driving. Will hopefully be back in the low 30's again soon

I was going to say only dropping 1-2 mpg isn't that bad at all. Then I saw your location...


Yea winter sucks for mpg. Looking back in september i was getting around 30mpg, now I am getting 25 thanks to the cold air and I have decent mods to up it too. Just something us northern states have to deal with every year.

 

[larson701]

About a 20% loss. The colder it gets, the more the mileage is reduced. The temperatures rose into the 30s last week and the mileage magically improved. We do have 'winter gas' to improve starting. I use E10 consistently and am experimenting with E30 since it became available.

 

[i12drivemyMP5]

Wish I could run E0 but even with 10% I still get 25mpg with or without AC, summer or winter, nice or aggressive driving. Sportauto tho............

 

[cutchemist]

Here in winnipeg i was getting around 24 until the coldest mmonth of feb. Now it gets around 20 in the constant-30 degree celcius.

 

[CheeseHelmet]

I've been getting around 8-9L/100KM (~27.5mpg) highway and I saw as bad as 13L/100KM (18mpg) for just city driving. The performance increase is noticeable which is pretty cool, on the highway when I give it gas in 5th it actually accelerates pretty damn quick compared to summer driving.

Why buy a cold air intake when you live up north?

 

[RABID_MP5]

we always think of the denser charge of colder air (at a given barometric pressure) for the engine. But don't forget that the drag coefficient applies to denser air too as you shoot thru the cold stuff. I looked it up once and it can be like a 10 per cent difference. But I need to look at the summer humidity offset, for folks not in the desert.

 

[stjohans]

I didn't really notice a drop in mileage until i put my remote starter in and always let my car run for 15 minutes before driving. in summer i usually get 9-10L/100km in winter its between 11-12L/100km