PCV System Set Ups???
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From: Tampa, FL
PCV System Set Ups???
I'm curious as to how some turbo RX7 owners have their PCV system set ups mounted. Does anyone use a vacuum pump on a catch can or do you just route the vacuum line to the air inlet pipe for the turbocharger? Do you just leave the nipple from the catch can venting to atmosphere?
I just want the best setup for relieving any blow-by into the oil system. Thanks
I just want the best setup for relieving any blow-by into the oil system. Thanks
Joined: Feb 2001
Posts: 29,798
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From: London, Ontario, Canada
I'm assuming here that someone has performed an emissions removal on the engine so you are starting from scratch on the PCV system.
Route the nipple on the oil filler neck to a T. One leg of the T connects to the fuel tank vent. The other leg of the T goes to a check valve. Flow direction of the check valve goes to a vacuum nipple on the intake manifold.
Bottom nipple on the center iron connects to a catch can.
If you have the stock ECU, the vent of the catch can connects to the TID after the AFM.
If you have a standalone, you may simply place a filter on the catch can vent.
Route the nipple on the oil filler neck to a T. One leg of the T connects to the fuel tank vent. The other leg of the T goes to a check valve. Flow direction of the check valve goes to a vacuum nipple on the intake manifold.
Bottom nipple on the center iron connects to a catch can.
If you have the stock ECU, the vent of the catch can connects to the TID after the AFM.
If you have a standalone, you may simply place a filter on the catch can vent.
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Joined: Jul 2014
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From: Tampa, FL
Alright thanks! However, I want to keep my intake system free of any "dirty" vapors coming from the oil system (In this case the nipple underneath the oil cap). Instead of pulling a vacuum through the intake manifold, could I just route the line to the same catch can as the line coming from the intermediate housing?
Joined: Feb 2001
Posts: 29,798
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From: London, Ontario, Canada
Air is pulled from a fresh air source into the lower nipple which leads to a passage deep in the engine around the middle of the eccentric shaft. This is done by applying vacuum to the upper nipple. This draws out all the contaminates from the crankcase like moisture, blowby, etc. These are brought into the intake manifold and burned so pollution from them is minimised.
If you just route both lines to a catch can, you have eliminated totally this ventilation system and essentially rendered the entire PCV system pointless, just turning it into a blowby oil catch system. Sure, it will catch blowby under high throttles. But for 99% of driving, no circulation will take place. Among other things, moisture will build up and deposit itself inside the engine. Most visible will be in the oil filler neck where the gunk will accumulate and begin to rust it from the inside out.
There is a reason every PCV system since the 40s has routed the line into the intake manifold.
If you just route both lines to a catch can, you have eliminated totally this ventilation system and essentially rendered the entire PCV system pointless, just turning it into a blowby oil catch system. Sure, it will catch blowby under high throttles. But for 99% of driving, no circulation will take place. Among other things, moisture will build up and deposit itself inside the engine. Most visible will be in the oil filler neck where the gunk will accumulate and begin to rust it from the inside out.
There is a reason every PCV system since the 40s has routed the line into the intake manifold.
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