Blow-off Valve (Diverter Valve)
A blow-off or diverter valve releases boost pressure when the throttle closes, protecting the turbo.
What is Blow-off Valve (Diverter Valve)?
Diverter valves recirculate the air into the intake; blow-off valves vent to the atmosphere. Many are electrically controlled. Diaphragms can tear with age. The familiar "pssh" sound comes from vent-to-air types; most standard cars recirculate quietly.
How it works
When the throttle closes, pressure opens the valve and lets the trapped air escape.
Why it matters for your car
A leaking valve causes low boost and lack of power. Aftermarket vent-to-air valves can upset fuel metering on MAF-based engines.
Other terms
- Airing Down (Lowering Tyre Pressure Off-Road)
- Battery Charger (Smart Charger)
- Big Brake Kit
- Blind Spot
- Boot Lid (Trunk Lid)
- Clay Bar (Paint Decontamination)
- Coachbuilder
- Engine Warm-up
- Exhaust Manifold
- Firing Order
- Intelligent Battery Sensor (IBS)
- Oil Drain Plug
- Oil Pump
- READY Indicator (EV And Hybrid)
- Running Boards
- Starting Handle (Crank Handle)
- Strut Brace (Strut Tower Bar)
- Tachometer (Rev Counter)
- Voltage Drop Test
- Wheel Balancing