O.E.M. Recirculating B.O.V.

The OEM recirc bov allows a flow of "charged" air back into the intake system, which allows the blades on the turbine to gain momentum again after the pressure has dropped due to deceleration, or reaches a certain level where it assists the blades in spinning.

With an Air Filter such as the Apexi C.A.I. you will hear the air flowing into it constantly, whereas with the standard air box it isnt as noticeable.

Removing the factory recirculating unit is not advisable unless you either have a roller bearing turbo setup, or intend on replacing the O.E.M. turbo unit as the recirculating system is there to keep the turbo spinning up when the pressure is let off the throttle for a gearchange. as it runs a single shaft for the turbine / compressor blades.

To explain, the turbo is spinning up quickly during acceleration, when acceleration stops, the turbo slows down, but the air released from the recirc bov allows the turbo to begin spin up for the next accelerating revolution. The force of the inertia is controlled with this system, removing it will put the turbo shaft under a lot of pressure and could break it.

With roller bearing turbos this is different, as the blades spin around a shaft on the bearings, and therefore can handle removal of the recirc system and having the Blitz B.O.V. fitted.

Non OEM BOV's

In the pic (click to enlarge)  below is the Blitz Dual Sound B.O.V. - however I only have one "trumpet" for it.

The bov is fitted to a custom pipe leading toward the inlet manifold.

Turbo "Chatter"

Theres a lot of talk on this subject, some say its the turbo on its way out, broken spring in the Actuator, or a broken spring on the P.R.V. - I have looked further into this and asked a friend who studied motorsport at Oxford University and he has cleared it up for me.

Turbo Chatter comes from the P.R.V and is due to excess pressure being released over a short burst, and therefore bounces the valve up an down, giving the "chatter" effect. Its usually found happening in high performance modified engine & turbos.

Can my Blitz chatter?

Simple - Yes it can, you need to adjust the bov to the correct setting for the car to run correctly, without it stalling. This can be found in the Blitz BOV Setup in the Guides / How To's section.

So the choice is Performance, or sirry ritter noise. you choose.