Since 1994, both GReddy and HKS have been creating aftermarket exhaust valves for turbo car tuners. Although they essentially do the same job and complete the same task, there are many differences between the GReddy Type RS BOV and the HKS SSQV BOV. Each has its own set of advantages and disadvantages; however, many turbo tuners trying to decide between the two wastegates always seem to be torn on which one to buy.

To help you decide which to buy, here’s a comparison of the GReddy BOV and the HKS BOV, both in BOV sound and performance.

BOV-Sound

For many people, the sound of the exhaust valve is the most important part. When they go down the street, they want to be able to change and make the sound effect enhance the look and quality of their customizations, so having a quality exhaust sound can really grab people’s attention and make a statement. .

The GReddy Type RS BOV releases its extra air pressure slowly, which makes it sound like it’s blowing air. There isn’t really a loud sound, but rather a subtle rush of air, which sounds exactly like air coming out of an air compressor. For many people, this is simply not “cool” as it is not loud; however, sometimes staying discreet isn’t exactly a bad thing, especially when you’re driving down cop-infested streets.

On the other hand, the HKS SSQV BOV can actually be three different sounds. It can have a no-insert insert, a three-arm insert, or a circular insert, which goes in front of the exhaust valve release port of the valve. Leaving the inserts out allows you to have a quiet sound, like the GReddy Type RS BOV, while putting in either insert will allow you to have two very distinct and performance BOV sounds.

BOV Yield

The two dump valves work very differently, even though they perform exactly the same task. The GReddy Type RS BOV works with a “push” valve, which allows additional air pressure to simply push out of the valve, once it reaches the valves threshold. This design is used on many exhaust valves; however, it does leave the possibility of the valve leaking and slow release.

The HKS SSQV BOV is a completely different design, as HKS wanted to design a “pull” valve system, which uses two valves and alternating pressures to open the valves and release excess pressure. This system is highly effective as it prevents any leaks and emits a solid burst of air which is released as soon as the valve is opened.