Really bad MPG since winter hit??

[Junkycosmos]

In MN I can outright see the MPG difference in all of our cars as they switch the GAS from Summer to Winter. Winter fuel having more originators (sp?) but bottom line is those displace the denser gas, gas being higher in raw BTUs (BTU = energy). Sure there are theories about Winter gas burning cleaner but don't most computers in cars from 92 balance fuel burn factors?


In winter time our e39, X5, Sienna and MX5 all drop 10% right as the gas changes. During the summer time I have also played with buying ethanol free gas in the lightweight MX5 (4-cylinder) see an average of 10% higher MPG with ethanol free there too.

Agree on the prior postings too of tire pressure. Huge drops in tire pressure with the crazy low temps and is something often missed. (air pressure in a tire typically goes down 1-2 pounds for every 10 degrees of temperature change).

Interesting thought on extra electric draw during the winter but would that be offset by massive draw for A/C compressor in the summer?

As for transmission shifting: I have no idea on the transmission programs based on temp but I can tell you my 2005 @ 90k miles is shifting better after replacing my AT Transmission Thermostat (part 20 here RealOEM.com * BMW E53 X5 4.8is MOUNTING PARTS F RADIATOR ) Transmisison is appears to be warming up faster and shifts very smooth again once warm.


some other ideas here via google:
http://www.topspeedracer.com/better-...an-winter.html