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BoxxerSix BoxxerSix is offline
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Join Date: Jun 2006
Location: Ballston Spa, NY
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Originally Posted by NathanUK View Post
Adam, is one of the reasons they did this so that when the car is off boost that air can bypass the turbo and the IC? This would help when pulling away in traffic, parking etc etc as the engine would not be under quite so much vacuum. Of course the air drawn in will not have gone through the turbo and picked up any heat from the turbo too.

I personally would fit it the way you describe for outright performance though

In either orientation the valve still opens at idle to allow an air bypass, it's just that when the bottom port is place to the boost pressure side(intercooler), upon a differential pressure change in the top chamber(throttle lift) not only does the valve have vacuum pulling the piston up to open but also has the boost pressure/flow pushing it open at the same time. In most cases with this type of valve(like the Forge DV pictured just above) this results in a faster reacting valve. No downsides at all to orienting it in this manner

the only two types of valves that MUST be positioned the other way are the pull type valves(HKS SSQV, Syncronic, etc) as they have a valve that looks just like an intake or exhaust valve and uses the boost pressure to seal against leaks. It's why those types of valves can run insane 60+psi boost pressures(diesel stuff) and not leak. They don't need spring pressure to hold the valve closed like all other piston type valves do
Adam Hennessy
Old 07-13-2008, 05:41 PM
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