One more catch can post

[conroe]

Just watched a vidio from Kevin Shaw on mounting a Riva catch can, and left scratching my head. When we added a catch can to a Chevy v8 or a v6 the can was always installed between the pvc valve and the intake, to catch the oil going into the intake manifold.
when the Rive is installed by-passing the pov valve, don't you create a positive crank case pressure?
Should the catch can be installed between the pov valve and the intake hose to the supercharger. This will create a negitive crank case pressure .
Don.t see any advantage the way Riva has there can mounted. But, what do I know. Happy Thanksgiving Jerry

[Team Bilford]

The TOPS valve is the PCV in this application. The line runs directly to the can from the TOPS. The hose that you plug is where the vapors would have been reintroduced into the induction system.

The line to the can is positive pressure from piston ring blow by into the crank case.

[conroe]

So what is the advantage or dis-advantage of having neg. or positive crank case pressure? Why have a catch can, just put a air filter on the end of a hose.

[Team Bilford]

So what is the advantage or dis-advantage of having neg. or positive crank case pressure? Why have a catch can, just put a air filter on the end of a hose.

You could put a breather filter on the end of the hose, but you would blow oil mist all over the engine compartment. The can and its baffle material removes most of the oil from the vapor and then it vents to the engine compartment.

[conroe]

What would happen if the catch can was mounted between the tops valve and the intake hose to the supercharger? This is the norman postion on a car.

[711jrp]

What would happen if the catch can was mounted between the tops valve and the intake hose to the supercharger? This is the norman postion on a car.

I think the issue with ski verses a car is ....lets say the catch can was half full (we're all lazy sometimes) if you hit a good wave it might be possible for the intake to take a big chug of the cans contents, this going through the charger ,inter-cooler and finally the engine is not a good scenario, this is unlikely to happen in a car. As you mentioned earlier negative crankcase pressure is desirable but I guess it's a case of the lesser of two evils as to how it's done the way it is.

[1tommygunner1927]

There are "catch cans" and air/oil separator cans:



Catch Can......



Air/oil (baffled) separator cans:


The Riva catch can vents to atmosphere, the baffled air/oil catch can vents to the intake. Both need to be emptied of gas/oil.

[Team Bilford]

What would happen if the catch can was mounted between the tops valve and the intake hose to the supercharger? This is the norman postion on a car.

There have been a couple of guys that have run the line back to the intake fitting. It will slow, but not stop the oil mist from coating the IC and SC. If you want to run a true separator, it might be ok.

[1tommygunner1927]

There have been a couple of guys that have run the line back to the intake fitting. It will slow, but not stop the oil mist from coating the IC and SC. If you want to run a true separator, it might be ok.

The baffled air/oil cans are much more expensive than a "catch can".