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Altitude Performance & Impeller Calculator

See how much power and WOT RPM you lose to elevation, heat and humidity — and how much to reduce your impeller's trailing-edge pitch to hit your target RPM.

Baseline — where your RPM was measured

Elevation ft I confirm this elevation is correct

Air temp °F Humidity %

Baro (sea-level) inHg

Riding location

Elevation ft I confirm this elevation is correct

Air temp °F Humidity %

Baro (sea-level) inHg

Engine & actual performance

Rated power (HP) Your tune's rated output Baseline WOT RPM Measured at your baseline location above

Engine type

Impeller & target

Current pitch RPM per 1° trailing edge

Only the trailing (second) angle is changed. ~100 RPM per degree is a typical starting point.

Target WOT RPM at riding location Leave blank to recover to your baseline RPM

Results

Density altitude

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Air density vs baseline

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oxygen available

Est. power at riding spot

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Est. WOT RPM (same impeller)

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RPM gap to target: –

Est. – RPM at riding spot → target – RPM

Suggested impeller pitch

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Re-pitching restores RPM and hole-shot, but not the lost power — top speed will still be slightly down.

Weather data from Open-Meteo. Estimates only — results depend on ECU strategy, intake temps, fuel, hull load and pump condition. Always verify with a WOT RPM log.