blow off valve

Fake Turbo Blow Off Valve Sound

A blow off valve is a pressure release system present in turbocharged engines, its purpose is to prevent compressor surge and reduce wear on the engine.


A compressor bypass valve (CBV) also known as a compressor relief valve is a vacuum-actuated valve designed to release pressure in the intake system of a turbocharged or centrifugally supercharged car when the throttle is lifted or closed. This air pressure is re-circulated back into the non-pressurized end of the intake (before the turbo) but after the mass airflow sensor.

A blow off valve, (BOV, sometimes hooter valve, dump valve) does basically the same thing, but releases the air to the atmosphere. This creates a very distinctive sound desired by many who own turbocharged sports cars. Some blowoff valves are sold with trumpet shaped exits that amplify the "pfssssst" sound, these designs are normally marketed towards the tuner crowd. For some owners this is the only reason to get a BOV. Motor sports governed by the FIA have made it illegal to vent unmuffled blowoff valves to the atmosphere. In the United States, Australia and Europe cars featuring unmuffled blow off valves are illegal for street use.


The unique sound caused by a blow off valve (but not a compressor bypass valve) sometimes comes at a price. On a car where the blowoff valve is mounted after the mass airflow sensor, venting to atmosphere confuses the engine control unit (ECU) of the car. The ECU is told it has a specific amount of air in the intake system, and injects fuel accordingly. The amount of air released by the blowoff valve is not taken into consideration and the engine runs rich for a period of time. Engines with a manifold absolute pressure regulated ECU or where the blowoff is mounted upstream of the MAF sensor are not affected.

Typically this isn't a major issue, but sometimes it can lead to hesitation or stalling of the engine when the throttle is closed. This situation worsens with higher boost pressures. Eventually this can foul spark plugs and destroy the catalytic converter (when running rich, not all the fuel is burned which can heat up on and melt the converter or leave heavy carbon deposits).


Blowoff valves are used to prevent compressor surge. Compressor surge is a phenomenon that occurs when lifting off the throttle of a turbocharged car (with a non-existent or faulty bypass valve). When the throttle plate on a turbocharged engine running boost closes, high pressure in the intake system has nowhere to go. It is forced to travel back to the turbocharger in the form of a pressure wave. This results in the wheel rapidly decreasing speed and stalling. The driver will notice a fluttering air sound.

A blow-off-valve is connected by a vacuum hose to the intake manifold after the throttle plate. When the throttle is closed, underpressure develops in the intake manifold after the throttle plate and "sucks" the blow off valve open. The excess pressure from the turbocharger is vented into the atmosphere or recirculated into the intake upstream of the compressor inlet.


Makes your car sound like a real turbo blow off valve

Make your car sound like a turbo charger! Attach our turbo whistler to your muffler exhaust pipe and under heavy acceleration makes your car sound like a fake turbo charger.

The turbo whistler is an aluminum device which easily fits inside your car or trucks muffler exhaust pipe. Under heavy acceleration makes your car sound like it has a fake turbocharger. In some cars letting off the gas pedal releases backpressure in the muffler making the car sound like it has a small blow off valve. All your friends will think you have a turbocharger under your hood!


The best part about our turbo whistler is that it only takes seconds to attach. No welding or drilling needed. You can easily detach the exhaust whistler and hear the turbo sound on all your friend's cars!

The turbo whistler measures about 3" long and is made of lightweight aluminum.

"I love my Turbo Whistler! Perfect Honda Civic turbo sound. I also tried it on all my friend's cars!"

- Gary Matthews

"After revving my car with the Turbo Whistler, my friends were curious what I had under my hood!"

- Chris Peterson

"I drive a cheap Honda Accord, but the Turbo Whistler makes it sound like I have a supercharger now!"

- Sara Dudash



Fake Turbo Whistler installs in seconds!  Turbo Whistle simply clamps to muffler exhaust pipe!

Price $49.95
Only $19.95


We also accept orders through PayPal below

All major credit cards and PayPal accepted
Your turbo whistler will be shipped same day ordered by USPS Mail with tracking number
Please allow around 3-5 days for delivery


Wholesale Orders - Link to Us - Video Contest - How to Install Turbo - Street Racing Videos - Drag Racing Videos - Sportbike Racing Videos - Drifting Videos - Burnout Videos - Car Makes Models - Car Clubs - Car Racing Videos - Auto Racing Videos - Formula 1 Racing Videos - Off Road Racing - Go Kart Racing - Car Crash Videos - NASCAR Racing - Muffler Exhaust Systems - How Turbo Works - Turbocharger Videos - Supercharger Videos - Exotic Cars - Dyno Videos - Demolition Derby - Indy Racing - Monster Trucks - Speedways - NASCAR Drivers - Concept Cars - Import Tuner Cars - Turbo Sound - How Turbochargers Work - How Superchargers Work - Car Shows - How Nitrous Oxide Works

Your fake blow off valve ships same day ordered by USPS Mail