Jetting for Vortex ROK Kart

The only app with all seven Vortex ROK engines. It works out the jetting for Vortex ROK kart engines with the DellOrto PHBG 18 and VHSH 30 carburettors, from the real temperature, humidity, pressure and altitude, and from the fuel you use.

WHY THIS APP
• All seven ROK engines with a DellOrto carburettor, from the Mini to the Shifter. No other app covers the SV, the SVR, the Shifter and the Mini U10.
• 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 high contrast, to read it in full sun with your helmet on.
• It alerts you when the weather changes enough to change the main jet or the clip, using the hourly forecast too.
• It takes your fuel into account: E10, E15, ethanol-free, CIK-FIA 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.
• A run logbook synced through iCloud, and your jetting shared with your mechanic as a link or a QR code, with no accounts.

ENGINES
Mini ROK and Mini ROK U10, with the DellOrto PHBG 18, and ROK GP Junior, ROK GP, ROK SV, ROK SVR and ROK Shifter, with the DellOrto VHSH 30: the ROK Cup classes that run a DellOrto carburettor. Each engine with its homologation, the identification sheet it runs under.

In ROK the rules only allow changing the main jet and the needle clip position. Everything else, needle, spray nozzle, idle diffuser and pilot jet, is fixed, and the app tells you the value your engine's sheet sets.

RESULTS
The recommended jetting for your conditions and your engine: main jet, needle and clip, spray nozzle, idle diffuser —on the engines that have one— and idle jet, plus air density, density altitude and relative horsepower. Two ±10 % fine adjustments, high and mid, to match it to your engine and how it is built.

FUEL
98 E5, E10, E15, ethanol-free, CIK-FIA, leaded race fuel, race E10, oxygenated, or your own with its stoichiometric ratio and density. With E10 the main jet goes up by about 1 % compared with 98 E5.

CARBURETTOR ICING
From temperature, 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, how much the density has changed since what you fitted, and how old the data is. When you start a track day, for 12 hours the main jet is on the lock screen, in the Dynamic Island and on your Apple Watch, and the app keeps an eye on the weather for you. Dark mode throughout.

CONDITIONS
From the nearest weather station or typed in by hand; it works the same without coverage. If you are at a track in the list, the app detects it and asks you whether that is the one.

ENGINE AND FUEL MIX
Engine and homologation, floats and their height, oil and track type; the carburettor comes with the engine. Fuel and oil calculator: choose what you want to know, the oil, the fuel or the ratio, and the answer is shown large, in litres, millilitres, US or UK gallons and ounces, as a percentage and as 1:n.

LOGBOOK
Each run with its conditions and its jetting, then what you actually fitted and how it went, lean, right or rich, in low, mid and high, with laps, best lap and maximum RPM. It syncs through iCloud across your devices and exports to CSV.

TRACKS
144 tracks with their altitude, taken from the track itself rather than the town, which are usually different. Choosing one sets the altitude and the track type. Search by the track name or by the town.

SHARING
As an image card, as a link or as a QR code: your mechanic opens it in their app or, if they don't have it, in the browser.

UNITS
°C and °F, metres and feet, mb, hPa, mmHg and inHg.