dump valve diameters, help.

[arjunior45]

does any one knows the diameter of the two big tubes in the oem dump valve? the small one is at 6mm, and I'm interested for the other two.

Or, does anyone know the Bosch part number {not the Alfa's} for the oem dump valve? Is the same valve used on Audi A4?

Nick

[AlfaJack]

It might well be the same. Part number is: 0280142106.

The two big tubes are 22mm internal diameter, so the pipe that goes over it is 25mm I think. The small one is only 3mm though.

[Brul(tm)]

oem dump valve?

You are going to replace the current one for the same OEM one? Why not an after marktet dump valve? there are better dump valves available then the Bosch OEM thing. You don't have to use an blow of valve which releases it free in to the air, you can always use a recirc (closed loop) valve.

Greetings,
Marc

[AlfaJack]

Yes the Bosch type can wear out. I have a TAS re-circulating valve on mine. Its good quality, but I am now awaiting a second hand HKS SSQV vavle. A friend has this on a Supra twin turbo and sounds very nice.

Here are some pics of the TAS one (have never been able to find them for sale on the web).

[arjunior45]

@ AlfaJack
thanks for the measurements.

and @Brul{tm}
well, to tell you the trough, I'm thinking to mount an adjustable {from 8psi to 16psi} blow off valve {open to air} and I need the dia for the connections.

But here comes another question:
If I mount an adjustable one, in an oem Q4 where do I adjust the pressure in the range 8psi up to 16psi?
Is it better to go for a wider range, for example 8psi up to 20psi or more?

Nick