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Best Aftermarket Air Filter – 9 Brands Comparison

Panel Filter Test

Do performance air filters really flow more air?

How much dirt do performance air filters let into your engine?

A Duramax enthusiast compared 9 air filter branda to find out which was the best aftermarket air filter. Which flowed the most air, which filtered the most dirt and which got blocked the fastest. You see read the full test results here.

Best Aftermarket Air Filter – Test Overview

Seven OEM-type paper air filters were compared against two performance air filters, the AFE Pro Guard 7 performance air filter and a K&N air filter.

Restriction (When new)

The difference between the best and worst flowing filter was only 0.06 PSI.

In other words, changing to a performance air filter will probably make no difference on power (on a stock engine)

Air Filter Filtration Quality

Which filter let the most dirt 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 only 0.4 grams of dirt through.

Long Term Performance

Which filter lasted the longest before becoming a restriction.

The papers filters were less restrictive than the performance filters.

The AC Delco filter was again the best air filter in the test, lasting 27% longer than the second place filter before reaching the blockage threshold.

And in addition, the second place air filter was also the filter that let the most dirt through.

Compared to the other air 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

Best Aftermarket Air Filter Test – Summary

The AC Delco replacement air filter was by far the superior air filter in this test.

The performance filters flowed around the same as the stock air filters, and the stock air filters flowed better than the performance air filters after they had been exposed to dirt.


From the results on this specific test, the AC Delco standard replacement was the best aftermarket air filter. It was far superior to the performance air filters and standard replacement air filters in all aspects.

The second place filter was the Baldwin filter.

Project Farm has done a very similar test to this
This page was last modified Mar 17, 2022 @ 4:14 pm


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