[Answered] Are Blow Off Valves Illegal – Know The Truth?

Are blow off valves illegal? The answer will surprise you as it depends on some states.

Blow-off valves are devices that are installed in a car’s exhaust system. They are designed to release the pressure that builds up in the system. When the pressure gets too high, the valve opens and allows the pressure to escape. This can cause a loud noise that sounds like a car is revving its engine.

Many car enthusiasts enjoy the sound of a blow-off valve, but are they legal? In this article, we will explore the legality of blow-off valves and whether or not you can get in trouble for having one on your car.

Are Blow Off Valves Illegal: A Complete Overview

Venting into the atmosphere is considered illegal. In that sense, using blow-off valves are illegal in some states because it can increase the amount of pollution emitted from a vehicle.

However, the benefits of having a blow-off valve are that it can help to prolong the life of the compressor, and it can also help to prevent damage to the equipment. By releasing the pressure from the compressor, the blow-off valve can help to reduce the amount of wear and tear on the equipment.

Additionally, the blow-off valve can also help to prevent the overloading of the compressor. When the pressure in the compressor is too high, it can cause the equipment to overheat and break down. By releasing some of the pressure, the blow-off valve can help to keep the compressor from overheating and breaking down.

They are praised for the performance benefits that they offer to car enthusiasts. But there are some downsides to blowing off valves that many people are unaware of. The release of compressed air from BOVs can be harmful to the environment in several ways. The most direct way that BOVs negatively impact the environment is through the noise they create. The sound produced by BOVs can be loud and disruptive, especially when multiple cars equipped with them are driving close to each other. Moreover, this noise pollution can lead to increased stress levels and disturbed sleep patterns in humans and animals.

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Another way that BOVs harm the environment is by releasing harmful chemicals into the air. When the air released from a BOV contains chemicals like carbon monoxide or nitrogen oxide, it can contribute to smog and other forms of air pollution.

While blow-off valves are not illegal in all states, there are some places where they are considered legal. However, the BOVs or the blow-off valves are legal to use if you have plumed them back inside the intake system.

Now, we are going to discuss whether blow-off valves are illegal in several states or not. Have a look-

Are blow-off Valves Illegal In California?

The answer is no. Then are blow-off valves legal in California? Well, it depends. If the car comes with a blow-off valve to recirculate air inside it, it’s not considered illegal in California.

Are Blow-Off Valves Illegal In NSW?

As they work by releasing pressure from the turbocharger, which will produce more emissions. For this emission to the atmosphere, using blow-off valves in your car is illegal in NSW. In addition, blow-off valves can be loud and disruptive, which can be a nuisance to other drivers.

Are blow-off Valves Illegal In Western Australia?

In Western Australia, they allow the blow-off valves if they come with the car itself and don’t vent into the atmosphere. Otherwise, it’s illegal in Australia too.

This Video May Help You Find More about BOV!

Frequently Asked Questions (FAQs)

Is It Illegal To Have A BOV?

Having BOV is illegal in most states. However, some states will allow it if you make them plumbed back in the intake rather than opening them into the environment.

Can Any Car Have A Blow-Off Valve?

Turbo system cars can have a blow-off valve. Nowadays, the modern car has BOV from the factory to recirculate the air and reduce the sound.

Do Blow-Off Valves Hurt Your Engine?

The short answer is no. Blow-off valves will not typically hurt your engine. In fact, they can help protect your engine by releasing pressure and preventing build-up before it has a chance to damage any components.

Are Blow-Off Valves Only For Turbos?

In most cases, the answer is yes. The blow-off valves are typically for Turbos to release the extra pressure.

Does A Blow-Off Valve Make Your Car Faster?

Yes, this allows the car to run faster because there is less stress on the engine. When the throttle is closed, the blow-off valve releases the pressure in the turbocharger. As a result, it doesn’t damage the engine but boosts its speed.


In general, the blow-off valve helps boost your car’s speed and doesn’t cause any damage. So it seems beneficial for your car. But the process of the BOV is harmful to our environment as well as it creates loud sounds too. That’s why using a blow-off valve is mostly illegal to use in big cities and states.

Hopefully, now you have gained an overall idea and clear out all of your confusion on “Are blow off valves illegal or not.”

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