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911nut 911nut is offline
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Join Date: May 2001
Location: Michigan
Posts: 2,511
Originally Posted by 911st View Post
CIS trubos are unique as they can not use a Blow Off Valve that vents to atmosphere.
Why? When the recirc valve opens it dumps the air into the i/c which dumps the air to the diaphragm valve which opens when the recirc valve opens. End result is that air is shoved into the engine behind the throttle plate. Meanwhile the metering plate has moved to the idle position. If you dump this air to atmosphere the end result is the same; the metering plate moves to the minimum flow position and doesn't know/care about which way the air went.
Paul B.
'91 964 Turbo
Port matched, SC cams, K27/K29 turbo, Roush Performance custom headers w/Tial MV-S dual wastegates, Rarlyl8 muffler, LWFW, GT2 clutch & PP, BL wur, factory RS shifter, RS mounts, FVD timing mod, Big Reds, - 210 lb
Old 12-04-2008, 06:50 PM
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