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staffanbe staffanbe is offline
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Join Date: Nov 2001
Location: Stockholm, Sweden
Posts: 66
Originally Posted by 911st View Post
Please. Do not use that valve on a CIS or other car that meters air flow before said valve location unless you just want to get bigger flames on throttle lift. Venting to atmosphere on a CIS motor with enough air can turn you hot turbo into a jet motor.

I used a piston style compressor bypass valve in a reverse orientation. Intake vacuum and boost kept it open at cruse and idle. I adjusted the spring so it had the right tension so the valve would start to close with loss of intake manifold vacuum. Then boost would build on the larger surface area of the upper chamber piston to force it closed against the boost that was trying to push it open. It is important for the upper chamber piston have significantly more surface area than the end of the piston in the lower chamber. I think most of the after market valves do.

The new Synchronic BOV I believe is adopting the same strategy I used with my $125 BOV 6 years ago.
So the pressure inside the intercooler is pushing the piston open during cruise since the BOV is installed reversed, is that what you are saying?

If so, don't I have the same pressure pushing the piston from both ends as long as the throttle isn't closed?
Old 03-17-2009, 07:14 AM
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