Do you get about 4 MPG less during winter ?

[TheSilkySmooth]

Originally Posted by 07WYarisRS

Almost guys .....


FI engines use more fuel in the winter because of the cooler air temps.
Cold air is more dense there for more oxygen... the engine compensates the would be lean fuel air mixture by adding more fuel.
Thats why carbed engines are adjusted and re-jetted for temp /altitude changes, thats also why racers test before the races for track conditions and ait temps/humidity etc...
Air temps play a huge roll on the F/A mixture

Sorry. Almost. After warmup, With the denser mixture you require LESS throttle opening for the same torque. So now you use less throttle and you're back to zero difference AFA air temp goes ( except during cold start enrichment) It's (1) longer warmup time due to COLD ENGINE not ambient air, (2) colder oils causing parasitic drag due to energy expended in shearing the lubricants, (3) higher drag and loss driving in snow.

extended explanation: A Heated air intake at cold start would help speed engine warmup and efficiency but generally the colder and denser the inlet air the more efficient the engine AFTER warmup. Water takes a lot of energy to heat - and your fuel is being expended in heating approx 2 gal H2O additional 40-90 degrees to Op temp in the cold winter days. There goes your fuel.
1 word - Block heater;)