Blow off valves

Blow off valve and DV - what are they?
Blow off and DV valves are the two most common types of valves. Blow off is an atmospheric valve, meaning it lets the excess pressure out of the engine's intake system, DV is a solution where the excess is let back into the intake system.

Blow off, or bleed valve of the pressure pumped by the supercharger unit, it is the BOV that is responsible for bleeding excess air from the intake when the throttle is closed, protecting the turbocharger from sudden stop of the rotors, greatly extends the life of the turbo. In addition to the turbo's protective function, your car also gains a boost in the sound of the drive unit with each release of the accelerator, which triggers the characteristic "pssst" sound coming from the open blow-off valve.

The second type is the dump valve (DV). Unlike the blow-off, the air released through the DV re-enters the intake piping, forming a closed circuit . Thanks to recirculation, it is much quieter than blow-off. DV will be appreciated by owners of series cars who care about the quiet operation of the blow-off valve. Any jamming as well as both piston blockage in blow-off or DV valves can result in damage to the drive unit. Therefore, it is important to choose proven products from reputable brands. In our offer you will find universal solutions and those dedicated to specific cars, which are characterized by simple installation on a plug and play basis.

Is it worth it to install a Blow-off or DV relief valve?
Due to the turbocharger's exhaust gas supply, it becomes problematic to control the boost it generates. It is not possible to stop the rotor suddenly, due to the exhaust gases constantly generated by the engine. In order to ensure the safety of the drive unit and turbocharger, it is necessary to use a valve that can directly bleed excess air from the intake system,

Closing the throttle triggered by letting off the gas causes a sudden blockage of air flow in the intake system, while still generating boost. This situation leads to an increase in the amount of air in the intake system, in the absence of the ability to quickly bleed it would damage the compressor rotor and bearings. For this purpose, engine manufacturers have constructed bleeder valves, in two variants DV and Blow-off, the latter especially found in mechanical tuning, providing additional sound effects.

Blow offs are much noisier than DVs, although the use of a particular type of blow off valve often depends on the type of engine, as some drive units(e.g. 1.8T) on a blow off valve often show errors. Two-piston blow offs such as the HKS SSQV 4 can help.

The DV or dump valve releases the vented air back into the intake system - before the turbo, thus creating a closed circuit. The use of DV is popular in serial cars or those that need to be "quiet". Dump valve performs excellently in this role. An interesting solution combining the features of both valves is the installation of special adapters directly under the DV, their installation changes the characteristics of the gun and makes part of the air is vented into the atmosphere, as is the case with Blow-Off.

How does the blow off relief valve work? What are the benefits of using it?
The principle of the bleeder valve is very simple. It is the pressure prevailing in the intake that is the controlling factor, reaching the limit value causes it to open, and the excess air is vented out of the system. Having a bleed valve is a necessary condition in supercharged engines. The benefits of a well-functioning Blow-off or DV valve are :

Extend the life of the turbocharger or compressor,

Smoother response of the drive unit to the accelerator pedal

Blow-off sound effects

Elimination of the adverse effect of pumping.

Blow-off in diesel engines
Until now, the installation of Blow-off was not possible in diesel power units, because the control of engine speed is done by fuel dosage, and not by opening the throttle . To meet the expectations of customers we have come out with an offer of adjustable Blow-off dedicated just to diesel, and the only condition that our car must meet is to have an electronic accelerator pedal, found in virtually all currently produced cars. Installation of the blow-off is very simple, and the sound effect does not differ in any way from the classic solutions for bleeding the boost pressure in throttle intake systems.