Jetting for DellOrto VHSB PRO

About

Work out the jetting of the Dell'Orto VHSB 34 on your Rotax Max or your Aprilia RS 125 from the real temperature, humidity, pressure and altitude, and from the fuel you use. WHY THIS APP • 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. • Track mode: your jetting large and at full brightness, to read it in the pits with your helmet on. With a Rotax EVO it marks what the RMC regulations let you change. • It alerts you when the weather changes enough to change the main jet, using the hourly forecast too. • It takes your fuel into account: with ethanol, ethanol-free, race or oxygenated 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. • A comparator for 113 needles with their real dimensions. • A run logbook synced through iCloud, and your jetting shared with your mechanic as a link or a QR code, with no accounts. ENGINES Rotax Max Senior, Junior, DD2, Supermax, Mini and Micro with their restrictors, EVO and non-EVO, following the Rotax Max Challenge technical regulations. Aprilia RS 125 and equivalent engines such as the Rotax 122 and 123. RESULT The recommended jetting for your engine, your conditions and your track: main jet, needle and clip position, air screw, diffuser, low circuit and floats, with air density and density altitude. You can create your own setups, compare them on the AFR chart and pick one as the reference. FUEL 95/98 (E5), 10 % ethanol (E10), 15 % ethanol (E15), ethanol-free, leaded race fuel, 10 % ethanol race fuel, oxygenated, or your own with its stoichiometric ratio. With 10 % ethanol the main jet goes up by about 1.1 % compared with 95/98. CARBURETTOR ICING From the temperature, the humidity and the chart civil aviation uses for carburettor engines. On a kart it warns of the risk at full throttle; on the Aprilia, which spends a lot of time at part throttle on the road, of moderate risk too. Weather always shows the dew point and whether there is a risk at idle. TRACK MODE AND TRACK DAY Your jetting full screen, with the temperature, pressure, humidity and altitude it is worked out from, how much the air density has changed since what you fitted, and how old the data is. With weather station data, it checks the station again every 15 minutes while it is open. When you start the track day, for 12 hours the main jet is on the lock screen, in the Dynamic Island and on the Apple Watch, and the app watches the weather for you. Dark mode throughout the app. WEATHER From the nearest weather station or typed in by hand. If you are at a track on the list, the app detects it and asks whether that is the one. NEEDLES Pick two from the catalogue of 113 and draw their profiles on the same chart, with real length, diameters and cones, to see where each one starts working. LOGBOOK Each run with its engine, weather and track, and then what you really fitted and how it went, lean, right or rich, at low, mid and high. Synced through iCloud across your devices and exported to CSV. ENGINE AND MIX Oil type, castor or synthetic, and a mix calculator: converts between fuel, oil and ratio, in litres, millilitres, gallons or ounces. SHARING As an image card, as a link or as a QR code: your mechanic opens it in their app or, without the app, in the browser. UNITS °C and °F, metres and feet, mb, hPa, mmHg and inHg, kg/m³ and lb/ft³.