EGR & PCV valves

From: W. Jack Hilton III (HEMI@charter.net)
Date: Wed Sep 09 1998 - 11:18:02 EDT


Chris -

I'll go out on a limb here and say that it doesn't matter as far as
performance .
Unless it was feeding raw fuel or nitrous back into the TB , I don't
think
that the amount of any type of gas that it would be recirculating would
be
enough to effect performance one way or the other .

Next time you look at a Pro-Stock car , see where they have the vents in

the valve cover breathers routed to . Every time I see them , they have
them running all the way down and exiting the gases at the end of the
headers .

Couple of points to this. The reason you have a PCV valve or breathers
is to keep the crankcase from getting pressurized from the combustion
process. Cylinder rings don't seat 100%, not even 95% in most
cases...which leads to blow by in the crankcase. The PCV valve is a one
way check ball that allows intake vacuum to keep a steady 'pull' on the
fumes and gases in the crankcase. On race cars there is a check valve
in the header collector that keeps backfires from going up the hose into
the valve cover. The exhaust gases rushing past create a little suction
on that hose that keeps a 'pull' on the crankcase. Still, a lot of
racers are using vacuum pumps now to ensure a good vacuum in the
crankcase. The vacuum is supposed to help with ring seal.

--
Drew Schofield
1998 Sport 4x4 5.2 CC Black



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