Quote:
Originally Posted by mwebb
the US EPA and IATn have conducted pretty thorough testing which shows that up to about 50% restriction of the air filter has about zero effect on fuel economy On Fuel Injected systems , it does reduce maximum flow and so will reduce maximum power output -
these tests were in response to the many false claims of various vendors including but not limited to K & N that replacing air filters could somehow magically improve fuel economy
it does not
as demonstrated by the test results in at least 3 separate sets of testing
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Those tests were on new throttle body or fuel injected gasoline powered cars. A clean air filter does improve mileage on diesels and cars with a carburetor.