Bypass Valve help...

This is for a modified 5KTQ setup and the 0-280-142-102 (borsch number on the current NEW valve) seems too weak. The spring doesn't seem strong enough. When the throttle is decreased slowly while under boost (1.3-1.8bar+) the car lurches as if the valve is completely dumping then snapping shut again. The current valves have not worked by themselves (ie. w/o the vacuum hose attached) The car will not make 1.2 bar as if the boost is leaking by the valve. In that setup, the system should be sealed and acting as if there is no bypass valve present. Seems that unless there is boost present in the vacuum actuator line, the valve will not stay shut under high boost situations. The current valve is brand new out of the box and replaced a thought-to-be faulty valve of the same number.

Any ideas?

Thanks, Nate

email @ snipped-for-privacy@copper.net or respond to group.

Go for the 034 145 710 N. This is what I have on my 96 S6 and it's also used on all the 1.8T engines as well as Porsches.

Tony

I have been told by my Audi specialist that surging can occur if the wastegate diaphragm is leaking. Is that any help?

-- IRL

UK 1989 Audi 200 TQ Avant (1B, full leather, hydraulic suspension) 223,000 miles and counting.........

Well, I would have too agree with that theory. When the valve is taken completely out of the system, there is no surging during throttle decrease under boost. There used to be an audible "stssssssssss" when the bypass valve actuated, now there isn't.

I still need the part number for the Bosch Sport 110. Or if anyone has a forged valve they want to sell....?? Thanks, Nate

The Bosch 110 is exactly the same as the Audi 710N - also used in SAAB Viggen. See this link

I swapped my 02 A4's with a Hyperboost.

--Cesar

= = Cesar Borgia =