Eric_Oz_S2

Can anyone confirm what this valve does connected to the breather hose between the throttle and AOS (part no 45). Is it a relief valve and does it let additional air in or does it vent additional pressure out? After 20+ years and covered in oil would it still do its job?

It is also used in 993s and is called an "air control valve"

Paulyy

I don't think i hadthat valve, either way i replaced that whole tube anyway with a rubber hose to the catch can.

My guess would be that it would decrease the vacuum once it gets to a certain point

Thom

On a stock set up with the factory AFM this valve is supposed to open to release the pressure shortly accumulated in the J-boot when the throttle body is closed after WOT, because charge air recirculates into the J-boot when the recirculating valve opens.

As far as I know this valve is a standard fitment on all K26/8 engines.

It is also used on 3.0 NA engines but seems to have been deleted on the latest 968s.