A fantastic air filter test was carried out by a Duramax enthusiast under lab conditions. You see read the full test results here.
Air Filter Test Overview
The tests compared 7 OEM type paper filters against an AFE Pro Guard 7 performance air filter and a K&N air filter.
Air Filter Restriction – Clean Air Filter
Between the best and worst flowing filter, the difference in restriction was only 0.06 PSI. In other words, all the filters flowed well, changing between filters should not make any difference in power.
Air Filter Filtration Quality
Which filter let the most air through?
The UNI and K&N filters were the worst performers, letting around 40% more dirt through than the other filters in the test. 7 grams and 7.9 grams respectively.
The best filter was from AC Delco which only allowed 0.4 grams of dirt through.
Long Term Performance
Which filter lasted the longest before becoming a restriction.
The AC Delco filter was again the best air filter in the test, lasting 27% longer than the second place filter, but the second place air filter was also the filter that let the most dirt through.
Compared to the other filters whose filtration was in the same league as the AC Delco, the Baldwin filter came in second but the Baldwin had a slightly higher restriction that the AC Delco
Panel Filter Test – In Summary
The AC Delco replacement air filter was by far the superior air filter in this test.
Flow When New
The difference in restriction of the AC Delco versus the most free flowing filter in this test was negligible and for sure not something that could be measured on a rolling road.
Flow When In Use
The AC Delco was the most free flowing air filter in the test, when the filters had been exposed to dirt.
The three air filters that plugged the fastest (plugged being defined as a 16 inches of water restriction) , two of them were so called performance air filters.
The AC Delco filter was flowing air 40 minutes after the performance filters had plugged, nearly three times longer.
Quality of Filtration
The AC Delco air filter filtered out 17.5 times more dirt than the K&N filter and 4.5 times more dirt than the AFE Pro GUARD7 filter.
The AC Delco filter flowed more air when exposed to dust, lasted longer and filtered more dirt.
A grand slam the AC Delco air filter was the clear winner in this air filter test with the Baldwin filter coming in second.
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