HowFast vs Revvo

Know your number before you stage. HowFast predicts your elapsed time using your vehicle's real specs — engine, drivetrain, tires, and the air conditions at your track. Whether you're dialing in for bracket racing or just curious how quick your car really is, HowFast gives you a data-driven starting point that gets smarter every time you run. Predict with confidence HowFast builds your ET prediction from the ground up — horsepower, drivetrain loss, tire grip, shift times, and real-time density altitude correction. The more you run, the more accurate it gets. HowFast learns from your actual timeslips and adjusts future predictions automatically. Built for the track, not the spec sheet! No expensive GPS hardware required. Use your iPhone's built-in GPS for run detection and timing, or connect to a RaceBox or Qstarz external GPS unit for precision timing at up to 25Hz. HowFast automatically detects your run and starts logging — no tapping required. Your logbook, is always with you! Every run is saved with your predicted ET, actual ET, speed, and conditions. Review your history, spot trends, and see how your tune is progressing over the season. Export Every Run in the DynoLog app effortlessly! HowFast captures your ET, trap speed, 60-foot time, and atmospheric data at the strip. DynoLog is where that data becomes a permanent part of your build record — plotted on a performance timeline, correlated to every mod you've made, and exportable as a professional PDF build sheet. After your pass, tap Export to DynoLog or login and the run lands in your build log automatically — no manual entry, no duplicate imports, no data left behind. Upgrade to Pro — one time purchase, yours forever. Unlock the full HowFast experience with a single one-time purchase: OBD-II connectivity— see your RPM, TPS, gear you're in, in real time Multi-run comparison — overlay runs and telemetry to find where you're gaining or losing Unlimited vehicles in your garage CSV export — take your data anywhere HowFast Pro is a one-time purchase. No subscription, no recurring charges. Whether you're a seasoned bracket racer chasing a perfect dial or a weekend warrior seeing what your car can do, HowFast is the smartest co-driver you've never had.

Time acceleration, analyze laps, estimate power curves and log every drive in one focused cockpit. No account required. MEASURE • 0-100 km/h (0-60 mph) acceleration with high-precision GPS timing. • 0-200 and 100-200 splits plus top speed. • Live lateral and longitudinal G-force. • Speedometer, elevation, distance and full trip stats. DYNO • Estimates engine power from acceleration, vehicle mass and body profile. • Shows the full curve and peak horsepower. • Add OBD2 to see RPM and torque in Nm. • Saves each result so you can compare runs over time. TRACK & LAPS • Automatic finish-line detection and lap timing. • Compare every lap and find your fastest one. STAGE • Record a stage and race against your reference run. • Real-time delta and split-by-split comparison, rally style. • Export and share the stage with anyone. LEADERBOARDS • Global rankings for 0-100, 0-200, 100-200 and top speed. • See where you stand and share your results with a QR card. MORE • Live Activity and Dynamic Island keep your run on the Lock Screen. • Apple Watch controls, current lap, best lap and Dyno result. • Siri shortcuts to start a test or trip. • ELM327 OBD2 and external GNSS receiver support. • Garage for multiple vehicles and a full history. NO FUSS • No account, no sign-up. Core features work right away. • Choose km/h or mph. Revvo Pro is a one-time purchase that unlocks Dyno, Track, Stage, every acceleration range and unlimited history. For closed circuits and private roads only. Dyno power is an estimate: enter the correct vehicle mass and always test in a safe, flat area closed to traffic.