[Z06] Catch can routing ?
Thread Starter
Instructor
Joined: Aug 2012
Posts: 161
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Catch can routing ?
I just picked up an 03 Z06 with a ton of mods to include a catch can. I'm no stranger to these cars or mods but the routing of the can has me scratching my head. I took a picture of it but it didn't come out great so I'll explain how it goes...
The valley port runs WAY out and into the air filter (seems like that would cause a vacuum leak). The valve cover port goes into the top of the can, and the intake port is in the side of the can.
Usually the valve cover port goes to the throttle body but this car has a FAST 90 with LS2 throttle body.
Am I right in thinking the valley port should run to the top of the can and the valve cover should go to the air filter?
The valley port runs WAY out and into the air filter (seems like that would cause a vacuum leak). The valve cover port goes into the top of the can, and the intake port is in the side of the can.
Usually the valve cover port goes to the throttle body but this car has a FAST 90 with LS2 throttle body.
Am I right in thinking the valley port should run to the top of the can and the valve cover should go to the air filter?
Melting Slicks
Joined: Nov 2013
Posts: 2,049
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From: USA
It will work either way, the goal is to have a clean air source come into the engine/crankcase and flush out/exit another path. Whether the fresh air is coming in thru the valley or valvecover, doesn't really matter.
I think for most cars the valley port tends to get less oil buildup and vapors, so for that reason it might not be a bad idea to switch the routing around.
I think for most cars the valley port tends to get less oil buildup and vapors, so for that reason it might not be a bad idea to switch the routing around.
Melting Slicks
Joined: Jul 2010
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From: Los Angeles
Pro
Joined: Aug 2006
Posts: 548
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From: Lexington KY
Does your has the external PCV valve on the line?..the the reason im asking when i installed my catch can and i left the PCV valve intact my car started to idale wierd specialy when I drive and i come to a stop light it will drop in rpm and then rev up...so when i remove it and hooked up the house straight to the catch can it runs fine....
Melting Slicks
Joined: Nov 2013
Posts: 2,049
Likes: 316
From: USA
if you have the older LS6 valley cover (03 Z06 you say, so i asssume you do)... however you route it, just keep the pcv valve between the intake manifold and can. Orient the valve such that air can flow into the manifold, but not from manifold into the can. If you have a 2004 valley cover, they switched over to a fixed orifice in the cover, which serves as the pcv valve basically-- so in that case, there is no external pcv valve.
Thread Starter
Instructor
Joined: Aug 2012
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Yes, I have a PCV valve coming out of the side port of the can and flowing into the intake.
Thanks for all the info...I swapped the valley and valve cover hoses around and it made a difference in the revs, haven't been able to drive it yet to see if there's a change there or not. It wraps up much faster now so I imagine it was causing a vacuum leak. The guy I bought it from may have drained the can and hooked it up wrong; he wasn't really well versed in the LS based stuff.
Thanks for all the info...I swapped the valley and valve cover hoses around and it made a difference in the revs, haven't been able to drive it yet to see if there's a change there or not. It wraps up much faster now so I imagine it was causing a vacuum leak. The guy I bought it from may have drained the can and hooked it up wrong; he wasn't really well versed in the LS based stuff.
Supporting Vendor
Joined: Aug 2013
Posts: 1,375
Likes: 301
From: Virginia
guys PLEASE you cannot go around modifying pcv lines all ***** nilly.
odds are if the car was running right when you got it, and that it was installed right.
all catch cans are not the same nor do the same thing, and most certainly do not all connect the same. you probably just created a problem for yourself that should be undone asap.
have you considered finding the manufacturer recommended connections and reviewing them? If you are worried that makes the most sense to me as a first step.
for example, what you describe is an optional connection for my pcv can, and hooking it up a way other than suggested will cripple or disable the ventilation system, leading to loss of performance, engine damage, fire, personal injury etc.
odds are if the car was running right when you got it, and that it was installed right.
all catch cans are not the same nor do the same thing, and most certainly do not all connect the same. you probably just created a problem for yourself that should be undone asap.
have you considered finding the manufacturer recommended connections and reviewing them? If you are worried that makes the most sense to me as a first step.
for example, what you describe is an optional connection for my pcv can, and hooking it up a way other than suggested will cripple or disable the ventilation system, leading to loss of performance, engine damage, fire, personal injury etc.
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Thread Starter
Instructor
Joined: Aug 2012
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Good call. I drove it Saturday morning and it stank of oil burning and got shitty mileage so I swapped it right back before I drove home from the cars and coffee meet. Ain't broke, don't fix it. lol