Sprint Filter P08 Air Filter for Road & Track – Indian Challenger Dark Horse (2020–2026) PM237S

There are two established ways of replacing a paper panel with something reusable, and they are not two versions of one idea. Layered cotton gauze wears a film of tacky oil and holds whatever touches it. The other route is what Sprint Filter builds: a woven polyester cloth that works dry and is never oiled at any point in its life. The difference shows in a published comparison, and rather less visibly in everything downstream of the airbox on a Challenger Dark Horse.

Key Features

• Woven polyester in one layer, run dry — no oil when new and none at any service afterwards
• 80 µm of filtration and 5,050 l/m²/sec of rated flow with the cloth clean
• Fibres from 22 µm in diameter; the aperture between them is a separate figure
• About double the filtering area of an ordinary performance filter, held in the standard frame
• Enters the series housing exactly as delivered, without modification and without remapping
• Blown clean and reused instead of discarded, specified for the service life of the machine, two years of warranty

Why nothing here is oiled

An oil film is a dose, and nobody fitting a gauze filter can measure the dose they have just applied. Too little and the medium works without the part that does the catching. Too much and the surplus has one direction available to it, which is the direction the engine is pulling. Throttle body, injectors and the sensing that meters fuelling all live in that direction. A dry medium deletes the question: nothing to apply, nothing to over-apply, nothing to travel — and no annual re-oiling to forget.

Dust held without a tacky surface

Dry is not the same as less capable. In the comparison Sprint Filter publishes, the woven cloth held back 93.13 % of the 100-micron particles put through it while four-layer oiled cotton reached 76.42 %. None of that makes the motorcycle faster: a slot-in element in an unmodified box has no route to more power, whatever it is made of. What can be claimed is an intake restriction that starts low and is returned to that figure at every cleaning. Where roads are genuinely dusty, this housing is also catalogued with a fine nonwoven at 14 µm and 1,800 l/m²/sec: more retention, much less flow, a trade and not a promotion.

Care and cleaning

Air first. Lay the line against the clean face of the PM237S and work outwards, so the dust leaves along the route it arrived by instead of being pushed further in. Greasy deposits need lukewarm water with a little mild detergent, rinsed until nothing further washes out. After that only open air at room temperature: no warming cabinet, no hot-air gun, no flame, since heat is what ends these elements early. Refit dry, with nothing sprayed on. The service instructions sit in the Downloads tab.

Fitment & Compatibility

Listed for the Indian Challenger Dark Horse of 2020 to 2026. The same element covers two further machines from the family over the identical years, the Challenger and the Challenger Limited — three entries on a single code. Confirm the year in the Fitment tab; that and the code identify the part.