Sprint Filter P08 F1-85 Air Filter for Racing – Indian Challenger (2020–2026) PM237S F1-85

The word on the label names a medium, not the motorcycle it goes into. Sprint Filter draws this weave for engines held near full throttle for minutes at a time and rates it at 15,000 l/m²/sec, three times the flow figure of the standard panel for the same airbox. On a heavyweight tourer that leaves one narrow question worth answering before anything else: how often does this machine spend a sustained stretch asking its intake for everything it has?

Key Features

• Woven polyester run dry, with no oil applied when new and none after any wash
• Filtration rating 85 microns at a rated flow of 15,000 l/m²/sec, the highest in the range
• Retention measured at 95.22 % of 100-micron particles; the standard weave returned 93.13 %
• Four-layer oiled cotton reached 76.42 % in that same published comparison
• Direct replacement in the series airbox: nothing cut, nothing moved, no remapping
• Cleaned and refitted rather than replaced, two years of warranty from purchase

The condition this weave was drawn for

A flow rating is a ceiling, and ceilings are only met under load. Long sealed-road miles at legal speeds, however many of them there are, do not hold an engine against that ceiling; a run of full-throttle pulls with corners in between does. Most Challengers will never see the second sort of day, and for them the standard 80-micron cloth is the sensible element while this one is capacity bought and never called upon. Where it earns its place is a machine worked hard on open roads by an owner who already knows the answer without having to guess at it.

What is not being claimed

It will not make the motorcycle stronger. A filter dropped into an unmodified airbox adds no power to a standard Challenger, whatever its rating, because intake, fuelling and exhaust were developed and homologated with an element in the middle of them. Nor is a more open weave free of consequence at the other end: this is the least restrictive medium listed here, and where the air carries a steady fine load the same housing is catalogued with a 14-micron nonwoven at 1,800 l/m²/sec that goes the other way. What is real is a low intake resistance that comes back to its original figure at every cleaning.

Care and cleaning

Air first, and chemistry only where air fails. Hold the line to the clean face of the PM237S F1-85 and work outward, so dust leaves along the route it took coming in. Where a wet month has left a film behind, lukewarm water with a little mild detergent lifts it; rinse until the water runs clear. Dry it in circulating air at room temperature and nowhere near a radiator, heat gun or naked flame, since heat is what finishes polyester. It is refitted dry, with nothing applied to the weave. The service sheet is in the Downloads tab.

Fitment & Compatibility

Catalogued for the Indian Challenger from 2020 to 2026, fitting the standard airbox without alteration. The same code is listed for the Challenger Dark Horse and the Challenger Limited across the identical span, three entries in all. Check the model year in the Fitment tab.