Drop in fuel economy
- Thread starter jesseh627
- Start date
walkingchaos
Member
- :
- 2014 CX-5
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 ) Since they got rid of MTBE there really is no such thing as winter fuel anymore. They dont 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) 
Last edited:
With 92k, I may be due some new plugs. Not sure how to clean a MAF, but I will look into it. I check my tire pressure frequently because of mileage and life of tires. Thanks all for the responses. Never thought much about the differences outside temps make on performance, but it is already warming up. Had some of the coldest days on record this Jan and Feb in TX, so maybe that is what is going on. Thanks again.
