Know which corner cost you.

The car's grip, braking and power as measured in the session, driven by a physics model on your best line through each group of corners. It shows the braking points and corner speeds that are within reach, and is rebuilt after every lap.

The top of the live screen is the gap to your reference lap, updated as you drive, green when you are ahead and red when behind. Below it, your speed against the reference at the same point, so you see where the gap is being made.

Each turn is split into four parts. As you leave it, the card shows the time each part cost against your reference and how much of the car you used, with the entry and apex speeds beside them.

A corner you pick is called like a co-driver would: "Next right. On my call." then brake, turn, power, full throttle on your optimal lap's points, every lap. For the corners that cost the most, the coach says the fix before, for example "Next left. Brake 30 metres later", and better, worse or the same after. It calls the lap at the line, and goes quiet in a corner that goes wrong. How it works.

The phone alone times every lap. You can also pair an external Bluetooth GPS receiver; the satellite count and the receiver's state sit at the bottom of the live screen.

Stopping saves the session. Resume it later and the new laps join it, with the lap that spans the break flagged so it never counts as your best.

Every session opens on its best and optimal laps, the car's peaks (top speed, lateral and braking g, and engine temperatures and RPM with OBD), how consistent your best laps were, and the corners that cost the most against your optimal, each with the change to make.

Pick a lap and a corner: a satellite map with your line, traces of acceleration, braking, throttle and RPM, and a list of fixes for that corner with what each one costs.

Lap times, top speeds and apex speeds for every turn, the best and worst in each column marked. Breaks between runs stay visible, and from any lap you can analyse, share or export its overlay.

For each circuit, each turn's best and typical time, apex speed and braking, session after session, so you can see what actually improved. Filter to dry sessions only.

Note the tyres, cold and hot pressures and geometry for a session, save it as a named setup, and mark the surface dry or wet. Named setups show up in the trends.

The tyres on the car and its camber, caster and toe are stamped on each session as they were that day, from the garage. Change them in the garage later and the old sessions keep theirs, so a lap time always sits next to the setup that produced it, and the trends can be sliced by tyre and by setup to show what a change actually did.

Export any lap as a video overlay to lay over your camera footage in an editor: a keyed MP4 that works everywhere, or a transparent MOV or WebM. 720p, 1080p or 4K, at 30 or 60 fps, with the lead-in and lead-out you choose. With an OBD adapter it also shows RPM, throttle and engine temperatures.

Pair a Bluetooth OBD adapter and choose which channels to poll fast; fewer channels update faster. Each car keeps its own channels, custom PIDs and alerts. Optional: everything else works without it.

Keep every car you drive. The car you pick decides the OBD profile and is noted on each session.

Import RaceChrono sessions and they get the same analysis as laps recorded in LapTAR: optimal lap, corners, trends.

Choose the circuit before you start, nearest first; the start/finish line is already drawn for the circuits in the library, and the app recognises the one you are at. A circuit it does not know, you draw yourself.