Is your Air Filter costing you money?

[Pritch]

Driveability, fuel consumption and performance issues on a vehicle can cause motorists to assume the worst-- but the fix is sometimes a very simple one.
[full story (http://www.auto123.com/en/news/car-news/is-your-air-filter-costing-you-money?artid=107930)]

[klinc]

According to the U.S. Department of Energy a plugged air filter does not affect fuel economy. A study published in February, 2009 shows that while performance suffered significantly, there was no difference in fuel economy in cars equiped with a computerized fuel injection system, unlike the carburated models which did. The air filter manufacturers have used this story through out all of my years as a car owner and somehow neglected to correct the facts when fuel injected cars came along. Maybe we should now revise our recommendations when we cite reasons for changing the air filters in our cars. This report is found at:http://www.fueleconomy.gov/feg/pdfs/Air_Filter_Effects_02_26_2009.pdf

[Pritch]

thats interesting. I'm going to read that story tomorrow and respond. The logic for this statement, in addition to it being (possibly incorrect) common knowledge comes from my years of being around engine building and racing.If a filter is 'clogged' fairly badly, the piston has to do more 'sucking' or 'pumping' to draw air in. This wastes fuel, in any application I'm aware of anyhow. In fact, engineers commonly use a reduced pumping action (by freeing up air intake flow) to increase both fuel economy and performance. So there is 'something' to the logic anyhow. That said, many things can affect your fuel mileage for good or bad. Of course, being marketing folks, the air filter companies will exaggerate for their own advantage. I like the ones that say 'adds15 horsepower!' an air filter probably won't do that, unless the old one is made of concrete..