September 19, 2011 Products

Can a BOV damage my engine?

Will a Turbosmart Blow-Off or Bypass Valve (BOV/BPV) damage my engine?

The simple answer is NO! 


A Turbosmart BOV or BPV are designed and engineered to improve the performance of your turbocharger system and NOT damage your engine. 

All the benefits of fitting a Turbosmart BOV are listed below:

Reduced Turbo Lag

Most Standard BOV’s are designed to be open at low vacuum levels. Thus, reducing emissions. This is because most standard cars idle between 18 – 21 inHg. This means that when the engine is between full vacuum and 5 inHg the valve is open. As a result in the turbocharger needing to pressurize the intercooler and piping. However, before the intake manifold can be pressurized. It is important to note that the valve must be closed. This is because it allows the turbocharger to pressurize the intercooler and intercooler piping. Resulting in a delay in boost pressure.

Turbosmart BOV/BPV

Turbosmart BOVs are designed to be closed early. This reduces the time it takes to pressurize the intercooler and piping.

Plumb Back BOV's

All plumb back BPVs will be just open at idle. This allows them to begin to pressurize the intercooler and piping at 15 inHg of vacuum. Resulting in a reduction in turbo lag.

Vent to Atmosphere BOV's Including the Dual-Port

All vent to atmosphere BOVs including the dual-port are designed to be completely closed at idle. This results in intercooler and piping pressurization as soon as the throttle begins to open. Further, resulting in instant turbo response, as the valve is closed even before the throttle is open.

BOV Response

Due to the spring force required to keep the BOV closed at idle. The response of the BOV is reduced at low throttle openings. It may result in light cavitation from the turbocharger at low RPM. This level of cavitation is negligible as the turbo speed is relatively low. Therefore, the resulting stresses on the bearings are low.

A vent to atmosphere BOV can also cause slight over-fueling between gear changes. This is because a portion of metered air is released from the intake system. It is worth noting that over-fueling is not harmful to the engine. It just means the unburnt fuel will exit the engine as exhaust. However, if the slight cavitation and over-fueling are unwanted. There is another option in which most of the benefits can be achieved. It is with fitting a Turbosmart vent to atmosphere plumb back BOV. However, it will reduce the following:

  • Vent to atmosphere noise.
  • Slight cavitation. 
  • Slight over-fueling.

All BOVs (Except the Kompact Plumb Back Range) are tunable. This is great in allowing them to suit different applications and user preferences. Tuning the BOV to suit the users particular driving style and vehicle modifications has two main advantages.

  1. It can eliminate excessive over fueling.
  2. It reduce's light cavitation.

Increased Sealing and Pressure Handling Capabilities

Most factory turbocharged engines have a bypass valve which is installed to eliminate cavitation. Most bypass valves are mass made from inferior materials such as:

  • Injection-moulded plastic.
  • Pressed sheet metal.
  • Unreinforced rubber diaphragms.
It is imprtant to know that some bypass valves even have additional pressure ports on the underside. This is because at certain levels of pressure they open to stop the user from increasing the maximum boost level.

Designed, Engineered & Machined

Piston-type BOVs Including the Kompact and 38mm Range

All piston-type BOVs including the Kompact and 38mm range are made from aerospace-grade billet aluminium. They are carefully, machined to very tight tolerances. It is because of precision engineering and design that they are able to withstand any boost level. Furthermore, they will not vent under any boost conditions.

Race Port - Diaphragm-actuated Type BOV

The Race Port is a diaphragm-actuated type BOV. It uses a Nomex reinforced fluoro silicone diaphragm. It is designed with a continuous working pressure rating of over 150 PSI.

The Race Port and the 38mm BOV range feature O-Ring seals on the piston. This increases their sealing capabilities.

Most standard bypass valves have a level of acceptable pressure leak. However, to over come this leak. It means that the turbocharger needs to work harder to achieve the set amount of boost pressure. From factory, most engines are working the turbochargers harder than what is actually needed.

Turbosmart BOVs are designed to provide excellent sealing of the intake system. This results in reduced stress on the turbocharger when compared to the standard bypass valves. Furthermore, they will not leak air pressure regardless of how much boost the turbocharger is making. This is due to the fact that there are equalizing pressures on both sides of the piston.


High Flow

All BOVs are designed to maximize flow at their given size. All standard valves have small and restricted flow paths. This might be ok for a standard engine. However, they are inadequate when increasing the performance of your engine. This can lead to large cavitation at high turbo speeds. Therefore, it will put extreme stresses on the bearings of the turbocharger.

  • The Kompact Range is great as a factory upgrade compared to the standard BOV. It providies you with durability, response and sealing capabilities, without needing a lot more flow capabilities.
  • The 38mm range is perfect for medium modifications. When compared to stock, the 38mm range offers much higher boost levels and high power outputs.
  • The Race Port is designed to be used in extreme horsepower applications. It is useful when cavitation needs to be eliminated and the use of large frame turbochargers and a high flowing BOV is used.

Further Reading

The question, 'Can a BOV damage your engine?' Has been solved. If you want further reading check out the following related articles: