Jetting Max Kart for Rotax Max

Main jet, needle and spark plug for your pre-2015 Rotax Max, a logbook that learns from your engine and a mixture calculator. Micro, Mini, Junior, Senior, DD2.

This app recommends the main jet, needle position and spark plug for karts with pre-2015 Rotax Max engines —Micromax, Micromax without carb restrictor, Minimax, Junior, Senior, DD2 and Supermax— from the weather conditions and your engine setup.

The conditions can be pulled from the nearest public weather station using your location, or typed in by hand: with no signal the app works exactly the same.

FOUR SCREENS

• Results: the recommended jet in large type, with the exact calculated value and the two jets it falls between, in green when the choice is clear and in amber when it sits halfway. Also the needle position, the spark plug, the air density, the density altitude and the relative horsepower. Fine tuning works in steps of 0.1 and tells you what each step achieves.
• Conditions: temperature, pressure, altitude and humidity, each with its own unit. When you pull them from the station you see which one answered, how far away it is and when the reading was taken, with a warning if it is more than 30 minutes old.
• Engine: class, K27 or K98 needle, 3.6 or 5.2 gr floats and pilot jet, float height, spark plug brand, 12.5 or 8.5 venturi, airbox, oil percentage and track type.
• Track logbook: every session with the circuit —picked from a catalogue of 112, with its altitude—, the conditions, what the app recommended against what you actually fitted, how it ran at the bottom, middle and top, the laps and the best time. Exports to CSV.

MORE

• Auto calibration: once the logbook has enough sessions, the app spots whether your engine systematically asks for more or less than the recommendation, and offers to set it as your default fine tuning.
• Mixture calculator: tell it the petrol and the oil you pour and it gives you the percentage, or the other way round. One button carries that ratio to the engine screen.
• Share the setup as an image, to send it to the team group.
• Dark mode, system text size, VoiceOver, rotation and iPad.

UNITS

ºC and ºF; metres and feet; mb, hPa, mmHg and inHg; kg/m³, lb/ft³ and lb/gal.

PRIVACY

The app uses no trackers and collects no personal data. If you use location, the coordinates are sent only to look up the nearest weather station.

Available in Catalan, English, French, German, Italian, Portuguese, Russian and Spanish.

This app is NOT VALID for Rotax Max EVO engines, from 2015 onwards. For those engines you need Jetting for Rotax Max EVO Kart.