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Alan L Alan L is offline
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Join Date: Apr 2006
Location: New Zealand
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Originally Posted by beepbeep View Post
Connect boost hose to WUR trough a plastic T-piece. Let one side go to WUR and another to your filter box (or add one-way valve to it). This will make pressure going to WUR drop to 0.3 bar or so (depends on hose diameter, use small diameter hose so you don't have to bleed lot's of air or you idle will go up).

Thinking about this, Goran, are you sure it would work? I guess you have done it and know it will. But in theory, I would have thought you would have equalised pressure thru whole boost system. For instance, if your gauge reads 0.8 bar, you have same pressure everywhere thru your intake system after the turbo. So, 0.8 bar also arrives at Tee piece on WUR. You bleed a small amount off to loss, but you still have 0.8 bar in the system, so the remaining going into WUR is still at 0.8 bar? If you had a very narrow constriction into the WUR, maybe there is a small delay, but eventually it will still equalise with boost pressure?
Incidentally, I have found why the boost/vac port only works one way (boost). The chamber is actually closed off to the rest of the system and the diaphragm rests hard up on the base of the upper springs mounting - on top of the boost spring, ie under vacuum, it can't extend any further up to increase CP. It can only go down, under boost pressure to reduce CP. So, in mechanical WUR, CP is constant, except under boost.
Old 08-05-2008, 08:42 PM
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