FordNut
04-18-2008, 06:45 AM
I asked about this awhile back but had no pics, so maybe this time I'll ge a little more discussion going.
This is the PCV hose assembly used on Cobra, Trilogy, Whipple, and I assume even Kenne Bell roots or twin screw supercharger systems...
http://www.mercurymarauder.net/showcase/files/5/1/8/tn_CIMG0626.JPG
The small hose at the bottom right of the picture goes to the bottom of the intake manifold, after the supercharger and intercooler. The end with the PCV valve goes to the valve cover. The other end goes to the inlet plenum between the throttle body and supercharger inlet.
With this setup, there should always be some level of vacuum to the crankcase through the PCV valve. Under low load/non-boost conditions the vacuum should be higher on the bottom side of the manifold, so it should be pulling vapors into the combustion chambers through that path. I suppose the bypass valve is open at this time so it would still be pulling part of the vapors through the port in the plenum. Under boost conditions, the supercharger should be pulling at least a little bit of vacuum at its inlet, so the vapors can go through the supercharger and intercooler to be burned in combustion. I believe that explains the PCV part.
So under boost, it looks like a boost bypass is always present from the bottom of the manifold to the inlet plenum. I asked awhile back if there is a check valve in the bottom hose to prevent this and found that there is not one in that path, only the PCV valve. It appears to me that it would be easy to increase boost by installing a check valve in the hose to the bottom of the manifold. Any problems with this? Maybe under boost the airflow through the hose back to the inlet plenum blows out any accumulated oil in the bottom hose and fitting in hopes of vaporizing it and burning it? Wouldn't that foul the intercooler/heat exchanger?
Why not add a solenoid valve so you could have a high boost/low boost adjustment by flipping a switch instead of changing pulleys? Of course you would probably want to have a flip-chip for quick and easy change of tunes also to accomodate the different boost levels.
Any of this make sense? Comments, please?
This is the PCV hose assembly used on Cobra, Trilogy, Whipple, and I assume even Kenne Bell roots or twin screw supercharger systems...
http://www.mercurymarauder.net/showcase/files/5/1/8/tn_CIMG0626.JPG
The small hose at the bottom right of the picture goes to the bottom of the intake manifold, after the supercharger and intercooler. The end with the PCV valve goes to the valve cover. The other end goes to the inlet plenum between the throttle body and supercharger inlet.
With this setup, there should always be some level of vacuum to the crankcase through the PCV valve. Under low load/non-boost conditions the vacuum should be higher on the bottom side of the manifold, so it should be pulling vapors into the combustion chambers through that path. I suppose the bypass valve is open at this time so it would still be pulling part of the vapors through the port in the plenum. Under boost conditions, the supercharger should be pulling at least a little bit of vacuum at its inlet, so the vapors can go through the supercharger and intercooler to be burned in combustion. I believe that explains the PCV part.
So under boost, it looks like a boost bypass is always present from the bottom of the manifold to the inlet plenum. I asked awhile back if there is a check valve in the bottom hose to prevent this and found that there is not one in that path, only the PCV valve. It appears to me that it would be easy to increase boost by installing a check valve in the hose to the bottom of the manifold. Any problems with this? Maybe under boost the airflow through the hose back to the inlet plenum blows out any accumulated oil in the bottom hose and fitting in hopes of vaporizing it and burning it? Wouldn't that foul the intercooler/heat exchanger?
Why not add a solenoid valve so you could have a high boost/low boost adjustment by flipping a switch instead of changing pulleys? Of course you would probably want to have a flip-chip for quick and easy change of tunes also to accomodate the different boost levels.
Any of this make sense? Comments, please?