Can a BOV damage my engine? • Turbosmart • Engineered To Win!
September 19, 2011 News

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:

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

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.

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.

2. 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, and 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, which fits different applications and user preferences. Tuning the BOV to suit the user’s particular driving style and vehicle modifications has two main advantages.

  1. It can eliminate excessive over-fueling.
  2. It reduces light cavitation.

3. 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.

All piston-type BOVs including the Kompact and 38mm range are made from aerospace-grade billet aluminium. 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.

  1. Firstly, allow the engine to cool down before removing the Boost Tee from your vehicle.
  2. Next, identify the input nipple with the restrictor at the end. Loosen the input nipple and remove the ball and spring.
  3. Thirdly, check that the internal air passages are clear and free from debris.
  4. Re-install the boost controller by following the instructions for your setup
  5. Lastly, you will need to re-adjust your boost settings after the removal of the gate.

The RacePort 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 overcome this leak. The turbocharger needs to work harder to achieve the set amount of boost pressure. From the factory, most engines are working the turbochargers harder than needed.

Turbosmart BOVs are designed to provide excellent sealing of the intake system. This reduces stress on the turbocharger compared to the standard bypass valves. Furthermore, they will not leak air pressure regardless of how much boost the turbocharger makes. This is because there are equal pressures on both sides of the piston.

4. 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 stress on the bearings of the turbocharger.

    • The Kompact range is great as a factory upgrade compared to the standard BOV. It provides 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.

Here is a handy self-help guide to helping you with your Turbosmart install and answers to some of the most frequently asked questions we get here. Turbosmart recommends that you get your products fitted and tuned by a qualified technician. If you choose to install the product yourself, ensure you have all the necessary tools and technical knowledge to perform this task.

Thank you for picking up the latest Turbosmart catalogue. As we look back on 25 fantastic years of innovation and growth, we continue to look towards the future as we release some revolutionary new products that will cement our reputation as innovators and market leaders.

Please contact us here and fill out a quick form so that our team can efficiently help you!

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