Wide open throttle
Wide open throttle (WOT) means the throttle is fully open, letting the engine take in as much air and fuel as possible for maximum power.
- Gasoline engines: The throttle plates are completely open, usually by flooring the accelerator pedal. This gives the least air resistance and the most air and fuel, producing the most power (but uses more fuel).
- Diesel engines: There’s no throttle valve, so WOT means injecting the most fuel for the available air to reach the right mixture. If you add more fuel, you’ll get smoke.
- Steam engines: The throttle controls how much steam is sent to the cylinders.
What happens at WOT
- Manifold vacuum drops, so the engine can pull in more air.
- More air means more fuel is needed to keep the right air–fuel mix, which is managed by carburetors or fuel injection systems.
- This combination creates more power.
How it’s monitored and controlled
- Throttle position is read by sensors and sent to the engine’s computer (ECU) or onboard diagnostics (OBD).
- In modern cars, drive-by-wire systems can separate pedal position from throttle position, with the computer deciding how to match them.
- In older carbureted engines, fuel jets were designed to smooth changes in throttle and prevent hesitation.
In short, WOT is full throttle for maximum power, used when you want the engine to run as fast as possible, though it uses more fuel and can increase smoke in diesels.
This page was last edited on 2 February 2026, at 10:00 (CET).