Main jet, needle position and spark plug for your pre-2015, non-EVO Rotax Max — Micromax, Micromax without carb restrictor, Minimax, Junior, Senior, DD2 and Supermax — worked out from the real temperature, humidity, pressure and altitude, and from the fuel you use.
WHY THIS APP
• Made for non-EVO Rotax Max engines: K27 or K98 needle, 3.6 or 5.2 gr floats and 12.5 or 8.5 venturi, each with its own calibration.
• Apple Watch app, widgets and Live Activity: your main jet for right now on your wrist, on the lock screen and in the Dynamic Island.
• It alerts you when the weather changes enough to change the main jet or the needle, also from the hourly forecast.
• Track mode: your jetting large and high contrast, to read it in full sun with your helmet on.
• A logbook that learns from your engine: if it always wants a little more or a little less, the app spots it and suggests it.
• It takes the fuel into account: 98 E5, E10, E15, ethanol-free or race fuel.
• Carburettor icing warning, using the criterion of civil aviation.
• 144 tracks in 22 countries with the altitude of the track itself, and it detects which one you are at.
• Logbook synced through iCloud, and your jetting shared with your mechanic as a link or a QR code, no accounts.
RESULTS
The recommended main jet in large type, with the exact value and the two jets it falls between: green when the choice is clear and amber when it sits halfway. Also the needle position, spark plug, air density, density altitude and relative horsepower. High and mid fine tuning go in steps of 0.1 and show what each step does.
FUEL
98 E5, E10, E15, ethanol-free, leaded race fuel, E10 race fuel, oxygenated, or your own with its stoichiometric ratio and density. With E10 the main jet goes up by about 1 % and the needle by more than half a position compared with 98 E5.
CARBURETTOR ICING
From the temperature, the humidity and the chart civil aviation uses for carburettor engines, the app warns you when there is a risk at full throttle, and Conditions tells you whether there is one at idle and on the grid.
TRACK MODE AND TRACK DAY
Your jetting full screen at maximum brightness, and how much the density has changed since what you fitted. When you start a track day, for 12 hours the main jet is on the lock screen, in the Dynamic Island and on Apple Watch, and the app watches the weather for you. Dark mode throughout.
CONDITIONS
From the nearest weather station or typed in by hand; with no coverage it works just the same. If you are at a track on the list, the app detects it and asks whether that's the one.
ENGINE AND MIX
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, fuel and track type. Fuel and oil calculator in litres, millilitres, gallons and ounces, as a percentage and as 1:n.
LOGBOOK
Each session with its conditions and jetting, and then what you actually fitted and how it went — lean, right or rich — at low, mid and high, with laps, best lap and max RPM. Synced through iCloud across your devices and exported to CSV.
SHARING
As an image card, a link or a QR code: your mechanic opens it in their app or, without it, in the browser.
UNITS
°C and °F; metres and feet; mb, hPa, mmHg and inHg; kg/m³, lb/ft³ and lb/gal.
PRIVACY
No trackers and no personal data. Your location is only used to query the weather station and the forecast.
In eight languages.
NOT VALID for Rotax Max EVO engines, from 2015 onwards: for those, Jetting for Rotax Max EVO Kart.