cdr = Crankcase decompression regulator
allow me to add to Oldbull8's description.
i think many people dont understand that our engines are air pimps.(edited: pumps)
we control pressure in a cylinder with air and fuel to create a micro nuclear explosion (heavy on the micro & light on the nuclear)
we control this explosion with timing, and orifices to allow incomming and out going pressure.
while the first part most people understand, its the 2nd part that alludes us.
whats under the pistons is a sealed crank case with oil, and guess what else?
uncontrolled pressure from the pistons moving.
this is what the CDR does, it is designed to relief pressure, and capture oil.
this is why the factory plumbs it into the intake, to suck all those fumes and oil vapor into the engine again to "recycle" it.
the problem with road draft tubes, is that its not being pulled by anything but outside pressure.
and it smokes and flings oil all over, which some people dont give 2 ***** about and or, love it?
some people leave them in the intake.
the only thing this does is spits oil at the compressor wheel in your turbo, or down your intake. and is recycled.
excessive oil in the intake can cause symptoms of bad rings and bad valve guides.
because the pistons are igniting that mixture as well.
closing the system from your CDR to another spot that is affected by crank case pressure is not doing much, and will result in leaky seals.
another option is to run it through your exhaust.
this is the option i am running.
i have a piece of 1/2" pipe welded into the down pipe at a 50-ish degree angle.
i intended this to act like a venturi, and suck the crank case pressure out.
with a 1 way check valve threaded on to the pipe, and 3/4" hose to the CDR.
the problem of this set up that i have found, is that i installed the 1/2" pipe flush with the down pipe.
which acts like a venturi at higher RPM, but at lower RPM it introduces a pulse into the crank case, that works its way around the valve.
that is now causing me to leak oil out of my dipstick tube.
many say that excessive oil out of the CDR will leave nasty oily residue out of your tail pipe.
i have a new CDR and i get zero oil out of my tail pipe.
but then again, it leaks ever so slightly out of my dipstick..
i believe that the CDR design is a flaw to begin with.
its basically a tube in a tube, with some kind of filter to trap oil out of the vapor.
as a community, we need to design and test our own.
maybe we can delete the oil from the vapor then this will all be a mute point.
)
