If you are a skillful driver, one of your most valuable experiences should be the ease of controlling the throttle of super-performing vehicles. Also, professional mechanics use both blow-off valves (BOV) and turbocharger systems to tune a vehicle’s performance.
You might have seen drifters of race cars amplify the hissing sound of high-horsepower turbo engines. These are some automotive engine tricks that mechanics use when upgrading turbo engines.
Usually, they install quality blow-off valves (BOVs) to vent-off compressed air into the atmosphere. Without installing a BOV, your car’s turbocharger system will flutter and have pressure build-ups.
This condition could damage the engine of your car because of compression surges. Consequently, BOVs are useful because they protect internal combustion engines and optimize fuel consumption.
During gear changes when the throttle is depressed, blow-off valves often produce full boosts for more acceleration. However, all blow-off valves don’t produce that fascinating whoosh sound.
What determines the level of sound is the exit design of these valves.
This component controls the flow of outgoing air pressures from your engine’s induction system.
It might not be acceptable to install BOVs in some regions because of the emission requirements of the vehicle’s exhaust.
Additionally, BOVs might trigger slim chances of over-fueling between respective gear changes.
We understand that these minor downsides still can’t dissuade speed racers and enthusiasts of forced induction systems. Here are some of the best blow-off valves.
11 Blow Off Valve Reviews
#1. Turbosmart Kompact Plumb Back Blow-Off Valve
Do you need BOVs that are perfect fits for your turbocharger systems? This Plumb Back blow-off valve by Turbosmart is a full-recirculation system that is designed for Mazda vehicles. Also, this versatile OEM part is compatible with both Forester XT’s and Subaru’s flanges.
It comes with a built-in gasket and plumb-back systems that enhance the performance of the vehicle’s engine. The internal mechanism allows maximum flow of compressed air pressure too.
Since its superior structural integrity reduces the risks of air-leaks, there’ll be proper intakes of air into the vehicle’s combustion engine system. Apart from the flow of pressure, this model of Turbosmart Kompact is a great noise-reducing BOV.
#2. Go Fast Bits DV+ Blow-off Valve
The DV+ Blow-off Valve by GFB re-circulates and releases vented air quietly. It’s designed with a unique shape and internal mechanism that gives your turbo engine system a good tune-up.
Unlike other diverter valves, this GFB model’s built-in pilot activation system offers superior boost pressure. During normal manual gearshifts, your drivetrain will enjoy a quicker boost recovery.
This reliable turbo accessory is designed to serve for many years. Since it comes with a high-performance valve actuation (pneumatic) system, the vehicle’s throttle response will be more responsive.
Usually, vehicles with regular factory diverter valves are compatible with this blow-off valve. However, you should consider the specifications of your valve before installing this GFB DV+ BOV.
#3. Boomba Racing Blow-Off Valve
When choosing blow-off valves, it’s important to consider the vehicle’s fuel economy. Boomba Racing Blow-off valve is a special vent-to-atmosphere (VTA) turbocharger accessory.
It doesn’t flutter during gear shifts, and the differential pressure within its piston is controlled by a pre-loaded spring. Also, this valve’s internal mechanism comes with a pressure-tested (maximum 70psi) brass piston.
With this impressive pressure rating, you should be confident of using the Boomba Racing BOV for any heavy-duty turbo assembly.
Apart from this BOV’s efficiency, it has a durable aircraft-grade (billet) construction. Additionally, this BOV is compatible with the 2.0L EcoBoost model of Ford.
#4. Dewhel Universal Dump Valve BOV
This DEWHEL Blow-off Valve comes with a clean mounting clamp (V-Band) and it measures 50mm (1.98 inches). Other components in this blow-off valve include aluminum fittings, and a hose barb (10mm) that enhances actuator responses.
There are a dual-spring mechanism and a diaphragm for short-stroke responses. Also, its CNC-machined (billet) and aluminum alloy (6061) is sturdy. While shopping for this model of Dewhel Universal BOV, you see a range of the anodized body colors.
Usually, universal BOVs are great for turbocharger systems’ upgrades. With a well-clamped Viton O-ring, there’s a zero chance of air pressure leakages. Additionally, the valve’s shaft is Teflon-lubricated and resistant to wear.
#5. GReddy Blow-Off Valve
This model of GReddy Blow-Off Valve has the design of a floating Valve. Unlike the previous model that is designed with a push-valve, this FV-type’s comes with an adjustable dual-spring mechanism. Also, its silicone diaphragm system ensures adequate controls and preload settings.
While it’s compatible with flanges for regular models of GReddy blow-off valves, your turbocharger system will enjoy smooth flows of air.
There’s a little chance of premature valve lifts while using this BOV. Apart from the lift resistance, this BOV’s CNC-machined outlet is fitted with discharge ports.
They improve the intakes of surrounding air and boost the blow-off sound too. It is great for all retro-fitting applications for several GReddy RS and RZ models.
#6. Auto Dynasty Universal Type-S Blow-Off Valve
As an essential part of turbocharger systems, blow-off valves are designed to eliminate pressure surges.
This Blow-Off valve model by Auto Dynasty is designed with eight discharge ports. While these ports allow air intakes, they release air with distinctive sounds. Usually, air compressions cause surge and engine failures from high-thrust levels.
However, these built-in discharge ports help to relieve the pressure in turbo systems. More so, this 40mm blow-off valve doesn’t cause pressure fluctuations. It regulates the airflow and prevents instability when you close the throttle quickly.
Additionally, this blow-off (type-S) valve’s kit comes with a 2.5-inch flange pipe that’s compatible with the dump pipe flange (Type-RS).
#7. Paisley Universal Blow off Valve
A well-made BOV is a pressure relief system that prevents the turbo surges. This Universal Blow-off Valve by Paisley has an adjustable design. Its floating-valve style is attached with a funnel for air intakes.
Since the floating valve design of this BOV fits the surge tank, it can handle cases of negative or positive pressure displacements. Apart from improving the efficiency of your turbocharged engine, this blow-off valve’s internal mechanism preserves it.
When there’s no compression surge, BOVs ensure better performance. Also, Paisley’s recirculated BOV prevents excess fuel from burning out and leaving carbon soot on the car’s exhaust.
#8. RKX BOV With Turbo Splitter Valve
Do you need blow-off valves that are compatible with Volkswagen and Audi cars? This RKX model of blow-off valve can be used for some cars that have Mass Air-flow sensors (MAF) systems. Its diverter valve (splitter-style) has a precision-machined design, and it’s durable.
Normally, BOVs are reliable when they have more holding powers and are responsive to turbocharged engines. Also, you can run this BOV in both full recirculation and blow-off modes. It comes with a block-off plate and adjustable spring preload mechanisms.
Apart from Audi (TT, A6, A4, and S4,) models, this diverter valve is ideal for VW (1.8T and 2.7T) cars. Another impressive feature of this BOV is its resistance to drivability issues.
#9. GFB Respons Blow-Off Valve Kit
The GFB Respons Blow-Off Valve is an effective turbo management system. Unlike cars that have auto-venting valves and MAF (mass air-flow) sensors, this GFB Respons BOV doesn’t stall blow-off sounds.
More so, the diverter valve helps engines to conserve fuel and prevent turbo lags. During gear shifts, it boosts engine performance to about 30%.
Its venting configurations can be adjusted with a cap ring that comes with the kit. However, you can adjust the spring pre-load mechanism to achieve maximum responses.
While it’s easy to regulate the whooshing sound, this BOV allows proper air re-circulation of air pressure because it comes with a patented venting bias system. Other accessories in this BOV kit have been designed with superior quality.
Additionally, this diverter valve is compatible with two (universal hose or direct bolt-on) models of mounting flanges.
#10. Torque Solution BOV Adapter
A great way of boosting blow-off noise with the performance of your car is to use quality BOVs. This Blow-Off Valve by Blow-Off Valve is designed for (2007 to 2012) different models of Mini Cooper S.
After greasing the O-rings, it takes a maximum of 30 minutes to install and test this turbo accessory with your vehicle. Also, it produces a great blow-off sound that doesn’t throw a CEL (check engine light).
During manual gear shifts, this blow-off valve ensures a faster response for your turbocharged engine. One of the elements that make a durable blow-off valve is the strength of its material, and this adapter has a compact billet aluminum housing.
Since this BOV is compatible with the Engine Control Unit (ECU), it will prevent your car’s engine from backfiring.
#11. RKX Spacer Blow-Off Valve
One of the few blow-off vales with quality stainless steel mounting flange is the RKX BOV Spacer.
Unlike universal BOVs, this hybrid diverter valve doesn’t need many modifications. Instead, it’s compatible with other diverter valves and still provides a characteristic blow-off valve sound.
Some engine codes determine compatibility with this model of RKX BOV Spacer; CBFA, BPY, CCTA, BWT, CAEB, and BPG. Also, you replace diverter valves of Tiguan, Jetta, Passat, GTI, GLI, and Q5 with this RKX BOV.
By re-circulating the boost pressure and forcing air into the atmosphere, you can enhance your turbo engine’s performance and amplify the classic sound. Furthermore, this diverter valve spacer comes with a quality machined billet construction.
How To Choose The Right Blow Off Valves
You wouldn’t like to experience the hassles of using substandard blow-off valves for turbocharged engines. This section of our buying guide helps to identify BOVs with decent constructions, and enhanced performance.
The first factor that determines the right BOV for cars with turbo engines is compatibility. By considering the design of favorite blow-off valves, you might discover their discharge ports, mounting hardware, and mode of operations.
More so, popular models of BOVs have diameters of between 40 to 50 mm. Usually, buyers prefer universal BOVs because they fit a range of cars. Hybrid BOVs might not need many modifications, but they fit specific types of turbo engines.
Ease of Installing BOVs
It’s easy to see BOVs with two mounting holes, but many of them still have three bolt-on hardware. However, it’s important to consider the specifications of your turbo engine’s BOV before going for it.
Usually, manufacturers recommend professional installation and they might not include set-up manuals in these kits. While the installation of blow-off valves are quite easy, they need to be mounted carefully.
When the attachment between the base of the mounting flange and the intake valve is not firm, it can cause a decrease in pressure.
Consequently, the holding power of your BOV will be reduced. Usually, easy-to-install BOVs should take more than 35 minutes. Ensure to make necessary adjustments; use hex screws and quality bolts.
All BOVs don’t have great ‘whooshing’ or ‘hissing’ sound ratings because this feature depends on the exit’s design. While some exits have trumpet shapes, the sound from other blow-off valves is determined by their internal components, shapes, and designs.
Since all blow-off sounds are measured in decibels, it’s important to buy premium blow-off valves. Also, some sounds from top-rated BOVs might be more appealing, but don’t forget to consider tolerable levels of sounds in your location.
Frequently Asked Questions
How does the BOV work?
The goal of any BOV for turbocharged engines is to vent excess air pressures and create a special sound.
Drifters and car enthusiasts often like this feeling when let-off throttle under the boost. However, you might need to install a secondary valve that reduces the chances of engine flutters.
Apart from racing purposes, a BOV vacuum chamber improves the actuator’s response. This chamber often includes dual-springs, diaphragm, and valve mechanisms. Also, BOVs extend the lifespan of turbochargers and improve engine performances.
Can I damage my car’s engine after installing a BOV?
While it’s possible to incur unforeseen maintenance costs, a top-rated BOV must be installed properly.
However, well-installed BOVs don’t damage turbocharger engines. Instead, they reduce over-load and surges for compressed air pressures.
What Are Common Types of Blow-Off Valves?
While many BOVs have adjustable turbo-response designs, you will see two common types in the marketplace.
Vented blow-off valves discharge excess air pressure into the atmosphere, and they might have multiple vents. While it’s easy to install these types of blow-off valves, they produce distinctive whistling sounds.
However, re-circulated blow-off valves distribute air through the turbocharger system. Also, these types of blow-off valves are designed for cars that use Mass Air Flow (MAF) sensors.
Turbocharger accessories for internal combustion engines of cars come with different shapes and designs. However, the hissing sound that attracts on-lookers during gear changes is determined by the BOVs build quality.
We have selected some great BOVs with standard models in the marketplace, and you can compare their features before choosing a favorite BOV.
- 11 Blow Off Valve Reviews
- #1. Turbosmart Kompact Plumb Back Blow-Off Valve
- #2. Go Fast Bits DV+ Blow-off Valve
- #3. Boomba Racing Blow-Off Valve
- #4. Dewhel Universal Dump Valve BOV
- #5. GReddy Blow-Off Valve
- #6. Auto Dynasty Universal Type-S Blow-Off Valve
- #7. Paisley Universal Blow off Valve
- #8. RKX BOV With Turbo Splitter Valve
- #9. GFB Respons Blow-Off Valve Kit
- #10. Torque Solution BOV Adapter
- #11. RKX Spacer Blow-Off Valve
- How To Choose The Right Blow Off Valves