Diverter Valve Vs Blow Off Valve – What Are The Differences?

Turbocharged vehicles are more common than ever. These are not only more effective, but they also provide additional tuning options.

Still, there is a lot of misunderstanding among enthusiasts who want to tune their turbocharged engine about the matter of diverter valve vs blow off valve.

What are they? How do they differ from one another? You will find the answers to all your questions in this post.

We will explain how these items work and go through the reasons why some individuals use one over the other. Let’s dive right in!

What Is Diverter Valve In Car?

Diverter Valve Vs Blow Off Valve

A diverter valve, also known as a recirculating or compressor bypass valve, is a component of the pressure release mechanism used in several turbocharged engines.

You may find it on the turbocharger’s side. The valve’s main function is to take the compressed air in the engine and convert it through the input stream.

If it didn’t deflect the air, the turbo would begin to spin reverse as the air was drawn back into it.

Stock diverter valves prevent turbo lag by redirecting pressure wave return to the compressor input, keeping the compressor wheel spinning.

How Does Diverter Valve Work?

Its main function is to take the compressed air in the engine and convert it through the input stream. If it hadn’t deflected the air, the turbo would have begun to spin reverse as the air was drawn back into it.

When your car recycles air after the mass air flow sensor (MAF), it will estimate how much air is left till the throttle valve opens again.

Your manufacturer’s valves control how much power the turbocharger produces. The vacuum pressure will open the diverter valve when the engine is idling.

Once it is entirely shut, the turbo boost will kick in. Suppose this part is broken; you will experience sluggish throttle response, prolonged lag, or lack of boost levels.

By installing an aftermarket diverter valve, these issues are resolved. Notice that you must install a diverter valve if you run with a chip, as it will put a strain on the normal ones.

What’s A BOV (Blow Off Valve)?

A blow off valve (BOV) is considered the boost responsiveness enhancer between gear changes.

Still, the blow off valve purpose is to guard your dependable turbocharger against any harm that might be done while shifting gears.

What does a BOV do? It allows the extra pressure created when the throttle valve is shut during boost situations to be released.

After that, the shut throttle plate causes a burst of a boost to enter the engine and return to the turbo. This can severely hamper the performance of your car.

There are two types of blowoff valves.

  • Vented: The majority of its designs feature a trumpet near the exit vent to intensify the hissing blow off sound made when air is ejected.
  • Hybrid: It might be considered to be the better version of the former type since it circulates some of the air in the engine back to the input system, so the boost pressure does not have to start at zero.

Where Does Blow Off Valve Go, And How Does It Work?

Where does a blow off valve go? It is an independent component that should be installed in the intake pipework between the throttle plate and the turbocharger compressor.

The intake tract is attached to a blow off valve.

A vacuum chamber comprising a valve, a diaphragm, and a spring is located inside the main housing of the valve.

In response to pressure fluctuations, the diaphragm is drawn toward the vacuum source and compresses the housing’s spring as it reaches a specific vacuum.

The spring is attached to a blow off valve that lets out the extra boost pressure by pulling away from the seat.

You may regulate the pressure at which the valve opens on some blow off valve types with an adjustment screw. You can also easily switch out the spring to alter the activation point.

A blow off valve can temporarily make your car run rich between shifts based on how the vehicle is configured.

This problem may arise due to the airflow meter in the automobile had already measured the air released into the atmosphere.

Diverter Valve Vs Blow Off Valve – What Are The Differences?

Diverter valves and blow off valves differ in many aspects. Function-wise, they show dissimilarities in operation, air delivery, and suitability.

Their costs also set them apart, with diverter valves coming at a higher price.


Blow off valve vs bypass valve, which one is better? The former is the best choice for engines with more horsepower since it allows extra pressure to exit fast.

When it releases all residual pressure into the atmosphere, your vehicle’s boost pressure will have to restart at zero.

It may be really aggravating when you change, and the turbocharger lags at every speed.

On the other hand, diverter valves struggle with more powerful engines. As a result, it is the better choice for little turbocharged engines.

This valve can avoid tuning concerns by reinserting air after the car’s sensor. Since it can improve throttle response, it is frequently employed in production cars.

Air Delivery

BOV vs diverter valve, what is the difference in air delivery?

Unlike other cars that sound like lawn mowers, the stereotypical tuner automobile with BOV emits the recognizable “psh” sound when venting all of its boosts into the atmosphere.

This implies that if you release the throttle at 20 psi (pressure per square inch) of boost, the entire 20 psi boost is instantaneously vented to the atmosphere.

Meanwhile, the diverter valve does not release any air into the atmosphere. As an alternative, it recycles all unutilized residual charge pressure back into the turbocharger’s intake stream system.


Even though they both perform the same task, their approaches are very different and are suitable for different engine management types.

Let’s say your engine is equipped with the MAF sensor system; the airflow is metered after it reaches the vehicle’s intake upstream system.

In this case, you will require a diverter valve since it can divert the air back to your intake.

Meanwhile, due to the operation method of blow off valve, the engine control unit (ECU) will be unable to correctly fuel the engine, leading to rich air-fuel ratios, bad idle, stuttering, and even stopping.


Bypass valve vs blow off valve, which one is more affordable? Blow off valves are typically priced between $100 and $200, making them one of the less expensive turbo settings that increase turbo noise.

Meanwhile, the diverter valves often come at a higher price point, around $200 to 300$ on average. Still, keep in mind the price can vary depending on the brands and the products’ quality.

Frequently Asked Questions

Blow Off Valve Vs Diverter Valve: Are They The Same?

There is a myth that diverter valves and blow off valves are the same thing. In reality, this is not true. These two are entirely different types of hardware.

The former diverts the releasing air into the intake, while the latter sends air into the environment. If you want details about the differences between the two, you can recheck the previous section.

Should I Convert Diverter Valve To Blow Off Valve?

Converting a diverter to blow off the valve is not always as beneficial as you think. Since an aftermarket diverter valve can flow more air and steadily, it is superior to the factory one.

You won’t need to change to a blow off valve unless you want to upgrade from the stock turbocharger or the limitations of a diverter valve.

If you meet someone that converts their diverter to a blow off valve, chances are they only do it because of the pleasant sound it brings.

Do All Turbos Need Blow Off Valves?

No. Blow off valves are not suitable for every turbocharged engine. Instead, they may require a diverter valve. This is true for when you turbo an automatic car or a manual car.

Although they both complete the same job, their methods differ greatly.

Keep in mind that when selecting a valve, consider the sort of engine management that your automobile uses to get the best performance.

The Bottom Line

Where Does Blow Off Valve Go, And How Does It Work

Above is everything you need to know about the topic of diverter valve vs blow off valve. As you can see, there are a few considerations when deciding which valve is more suitable for your vehicle.

The most important thing to remember is that a blow-off valve releases all the boost pressure into the atmosphere.

Meanwhile, all surplus pressure is vented through a diverter valve and returned to the intake.

When it comes to removing extra pressure signals from the car’s turbo power system and avoiding compressor surges, both of them are incredibly effective.

Thus, ask the appropriate questions and do additional research before coming to the final decision to avoid making a poor decision and wasting your money.

Hopefully, you will find this post helpful.

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