It does for some cars...shouldn't hurt in the winter.
The thing is, I've heard of the ECU's on some cars adjusting to compensate, so some cars just return to their normal MPG after a while.
Originally Posted by theclencher
P.S. I must be a wierdo as I think just because a guy can afford to do something, doesn't mean he should. I can afford to buy 100 gallons of gas several times a month, pour it on the ground, light it (or not)... but I don't think I should.
Theoretically, the ECU plus amm or maf plus oxygen sensor should keep it running right about at stoichiometric ratio - the optimum air/fuel ratio. All the time, once it's been warmed up.
However if warmer air/fuel burns better, it should be better to have a warm air intake. Or where the constant inflow of cold winter air drains off engine heat which must continually be replenished from the combustion process - again, a warm air intake should be better.
Would be nice if someone with a ScanGauge or maybe a SuperMID could test this. However I suspect that most warm air intakes don't yank out of a car that easily - and back in either.
My warm air intake is feeding the engine air between about 48-60 degrees, with outside temperatures between 25-45. I'm sorry I don't have any documentation demonstrating that it helps FE. But it seems to be doing well.
Currently getting +/- 50 mpg in fall weather. EPA is 31/39 so not too shabby. WAI, fuel cutoff switch, full belly pan, smooth wheel covers.