Does a cold air intake help improve or does it hurt mpg? How does it do it? And is specter cold air intakes from autozone any good?
The MAF is a transistor that gets hot. The air flowing through it cools it. The more air, the cooler it gets. Cold air is interpreted as more air. And it is. Cold air is denser than warm air. Air volume is directly proportional to air density. The MAF and the o2's work together to maintain the ideal air/fuel ratio of 14.7:1. More air more gas. But it takes less pedal to achive the same rpm as before you put the cold air on. Giving the perception that the power increase is more HP than it really is. It levels off as you apprach WOT, or WFO if you race alot. So you're gas mileage will remain nearly the same as long as you keep your foot off the firewall.
simple fact - they don't work on injection systems in fact they cause the ecu to run a cold start program which enriches the fuel and wastes gas, if something as cheap and simple as an air filter increased power and gave better gas mileage don't you think the manufacturers would all fit them even as an option, also on lean burn engines the colder denser air would make the mixture even more lean leading to burnt plugs and valves, the ecu/maf/temperature sensor are all mapped together upsetting the balance would cause performance to deteriorate, the injection system squirts a measured amount of gas at each cycle so more or colder air would make no difference, unlike a carburetor which supplies gas continuously
