WattGrowl: Engine Sound Sim

Miss the sound of a real engine? WattGrowl is an EV engine sound simulator: it gives your electric car the voice of a combustion engine, synthesized live on your phone and played through your car's speakers over Bluetooth. No hardware, no OBD dongle, no wiring.

DRIVE IT LIVE
Mount your phone, pick an engine and drive. WattGrowl reads the phone's motion sensors and GPS, works out how hard you are accelerating, braking or coasting, and plays the matching engine note in real time: idle, pull, lift-off crackle, gear changes, turbo spool and blow-off. It calibrates itself to the way your phone is mounted and keeps the sound steady over bumps and rough roads.
Live Drive is the premium part of WattGrowl: try it with a 3-day free trial on the yearly plan, or unlock it for life with a one-time purchase. Everything else is free.

38 ENGINES, ALL SYNTHESIZED
Small-block and big-block V8s, a flat-plane screamer, twin-turbo straight-sixes, a rally boxer, a hot-hatch four, high-revving V10s and V12s, a quad-turbo W16, twin-rotor and quad-rotor rotaries, diesels and superbikes. Every engine is modeled, not looped: firing order, exhaust pipes, muffler, turbo, supercharger and limiter all shape the sound, so no two engine sounds are alike. Want a deeper V8 sound or a straight-pipe exhaust sound? Build your own in the Engine Workshop.

GEARBOXES AND DRIVING MODES
Car sounds with a gas pedal and gear changes, the way you remember them. Pick manual, dual-clutch, automatic, sequential, CVT or single-speed, and shift from on-screen paddles or your steering-wheel media buttons. Eco to Track drive modes change how the engine responds.

POPS, BANGS AND CRACKLE
Car pops and bangs, no mods required: WattGrowl doubles as an exhaust sound app. Lift off and hear overrun crackle shaped by that engine's own exhaust. Tap POP for a backfire at a standstill. Rally anti-lag, DCT upshift "brap" and limiter bangs are all there.

SOUNDS RIGHT IN YOUR CAR
This car sound app is tuned for real car speakers. Front/rear sound stage puts the intake up front and the exhaust behind you. Automatic latency compensation keeps the sound in step with the pedal over Bluetooth. Music ducking balances the engine against your playlist. A hearing-safety cap limits how loud the engine can play.

ALSO IN THE APP
• Free: engine simulator with an on-screen gas pedal and brake — try any engine anywhere
• Free: garage rev mode — rev the engine while parked, as often as you like
• Live Drive: throttle pad at traffic lights — rev at a standstill, back to gears when you move off
• Sound Studio: mix exhaust, intake, mechanical, turbo and pops on separate faders, plus a 3-band equalizer
• 0–60 mph, 0–100 km/h and quarter-mile timers, trip statistics
• Drive recordings to review and share
• Engine Workshop: edit every synthesis parameter, save your own engines
• Dark, glanceable dashboard with classic, modern, race and retro themes

GOOD TO KNOW
• The sound plays inside the car for you, the driver. It is not a pedestrian warning system and does not replace your car's AVAS, the electric car sound meant for people outside.
• Keep your eyes on the road: WattGrowl is designed to run hands-free once started. Set it up before you drive.
• Use the car engine sound simulator offline: every sound is synthesized on the phone, so no internet connection is needed to play.
• Location is used only to measure speed for the engine sound; nothing is uploaded.
• Works with any EV and any car stereo — connect your phone over Bluetooth, a cable or USB.
• Hybrids and gas cars too: pick your car type, or enter its horsepower and weight and the app works out the rest.

Built by an EV driver who missed the growl.