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8a We've had success using breathable air filter lids over solid lids in previous testing. This Spectre hpR filter element (14x4-inch, Spectre PN 880138) and 14-inch filter lid (PN 47612) with offer more airflow than the 14x3 paper-element, solid-lid air cleaner we used for the baseline. We only reused the 1-1/4-inch drop base from the 14x3 Proform air cleaner. The Spectre 14x4 filter with the 14-inch filter lid showed us 2 hp and 2 lb-ft torque at peak.