Quote:
Originally Posted by Justin.b
I am still curious why this would be preferred in any way to a standard BOV. A standard BOV acts on the pressure sifferential between the manifold and the charge tubing. This one's movements are controlled only by the manifold pressure.
It seems like you could futz around with this thing and eventually maybe get it to work, or you could just buy a standard BOV and have it work properly as soon as you set the spring tension. I fail to see the advantage of this one.
-Justin
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a standard push type BOV actually relies on the pressure difference between the vaccuum tubing and atmospheric pressure. there is a layer of atmo pressure between the charge tubing and the vaccuum line layer. A diaphram separates the vacuum line layer and the atmo layer, and the plunger between the atmo layer and the charge tube. The spring is there to control the speed of the plunger movement basically. the purpose of the spring isn't there to hold the plunger down. So in the end, a push type bov relies on the charge pressure to open the valve and fight against the spring. (this is the reason why a lot of people have problem with TiAL's, the box spring of 12lbs is too strong for a lot of engines and people don't get the lighter springs)
Pull type bov's take out the diaphram out of the picture and rely solely on the manifold to open and close the valve. HKS has a very light spring to hold the valve closed during idle however looking at synchronic's design, they don't have a spring and just use the poppet valve. Like you guys noticed it will pull air in during idle and high vacuum, but they have developed an "anti-stall" fitting on there that will keep unmetered air from coming in so that is no longer a problem. Not sure how the fitting works without a spring, but its supposed to work =T
HKS has proven the design works effectively, i just can't stand the whistle. There's even a slight whistle when the middle element is removed because of the sequential design of the thing...blah....and yes the HKS racing bov is not sequential, but costs twice as much.
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