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mark houghton mark houghton is offline
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Join Date: Jul 2008
Location: Central Washington State
Posts: 3,899
Decel valve delete and idle

Just a quick question, since I will probably be deleting my decel valve as part of my current BOV update project.

When seeing vacuum - such as in an overrun situation (off the gas coasting or shifting) the decel valve opens and directs additional air to the intake manifold (drawing that air from the stock secondary/boost recirc manifold)...thus bypassing the throttle valve and causing the rpms to hang up briefly. That's how it works, for some nefarious emissions reasons.

Now, here's the question: When at idle, that valve should be open as well due to the vacuum present, and a small amount of air should also be bypassing the throttle body valve and going straight to the intake manifold. Won't this additional air have an impact on idle rpm setting and maybe AFR's, such that once the valve is removed (deleted) the idle speed will have to be adjusted via the air correction screw?

Those of you that have done this delete, what are your experiences in this regard?
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 12-31-2009, 05:34 AM
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