PCV boost question
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
PCV boost question
When running boost do you have to block off your PCV(positive crankcase ventilation?) valve to keep the boost from going into the crank case? If so does anyone have any experience doing this on a '93 where the pcv is on the driverside under the fuel rail(or does it have to do with the tube going from the TB to the valve covers?)
Any help would be appreciated. Thanks.
Any help would be appreciated. Thanks.
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
Re: PCV boost question (StealDads67)
No it's not a joke. The PCV uses the vaccume in the intake to pull the gasses out of the crank case. I'm not sure if there is a problem when the vaccume goes to boost. I don't know the system well enough so I thought I would ask for help.
Le Mans Master
Joined: Oct 1999
Posts: 6,366
Likes: 34
Re: PCV boost question (mn_vette)
I think they move the PCV to the turbo intake to suck the pressure up?? or is it the tube that does not have a check valve? (what ever that is called)
But that is a good question.
I hope someone can tell us what is done to all the vacuum lines when adding boost. Do they all need check valves?
[Modified by bill mcdonald, 1:08 PM 1/28/2003]
But that is a good question.
I hope someone can tell us what is done to all the vacuum lines when adding boost. Do they all need check valves?
[Modified by bill mcdonald, 1:08 PM 1/28/2003]
Le Mans Master
Joined: Oct 1999
Posts: 6,366
Likes: 34
Re: PCV boost question (StealDads67)
:lolg: What?!? The boost goes into the cylinders..... Why would there be any extra PSI in the crankcase?......
Im guessing this is a joke right
Im guessing this is a joke right
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
Re: PCV boost question (bill mcdonald)
Is it ok to just put a valve cover breather on the end of that tube to relieve the pressure and cap off the TB port to keep from loosing boost?
Drifting
Joined: Dec 2001
Posts: 1,313
Likes: 1
From: providence ut
Re: PCV boost question (bill mcdonald)
The installation instructions from ATI on my 85 had me remove all the pvc lines and plug the manifold holes . I now have breather caps on the valve covers. :chevy
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Le Mans Master
Joined: Apr 2000
Posts: 6,341
Likes: 1
From: Shelton CT
Re: PCV boost question (StealDads67)
I thought replacing the PCV valve on the drivers' side is bad for the engine??
I have put a breather on my passenger side valve cover hole, but the PCV valve was deemed necessary from research and topics I have read on this and other forums. Anyone have any more info on this?
I have put a breather on my passenger side valve cover hole, but the PCV valve was deemed necessary from research and topics I have read on this and other forums. Anyone have any more info on this?
Instructor
Joined: Nov 2002
Posts: 142
Likes: 0
From: Coos Bay OR
Re: PCV boost question (mn_vette)
Yes I have had problems with capping off the crankcase ventilation tube and posted questions in past without reply.When capping tube check engine light comes on.ATI had no cure.Hope some can help.
Drifting
Joined: Feb 2002
Posts: 1,937
Likes: 2
From: Arvada CO
Re: PCV boost question (Gold nugget)
i agree mine is setup like this------>The installation instructions from ATI on my 85 had me remove all the pvc lines and plug the manifold holes . I now have breather caps on the valve covers.
Also my charger was installed by ATI and that is how they have it done...i have baby breather caps on my valve covers and capped off the intake and throttle body vacuum!
:D
Also my charger was installed by ATI and that is how they have it done...i have baby breather caps on my valve covers and capped off the intake and throttle body vacuum!
:D
Le Mans Master
Joined: May 1999
Posts: 6,517
Likes: 1,304
From: Windermere FL
Re: PCV boost question (mn_vette)
I think I have the answer to this. I put a beather on the pass side valve cover and left the PVC connected to the manifold. Plugged the port on the throttle body.
When positive boost is obtained, the PVC valve closes as to not let the boost leak into the crankcase. This is a builtin safety of the PVC system. It is needed when the engine backfires to prevent the backfire getting into the crankcase.
To see that I am correct, take the PVC hose off the manifold and blow into it. Don't forget to have a beer in hand to get rid of all the oil and gas flavor! Or you can use a mitivac if you are faint of heart. If the PVC valve is functioning correctly no air will go into the crankcase. If it does, replace the PVC valve.
You also may have the same concern with the power brake booster. It also has a check valve that will prevent boost from getting in.
The only one I am not sure of is the EGR and Vapor canister.
When positive boost is obtained, the PVC valve closes as to not let the boost leak into the crankcase. This is a builtin safety of the PVC system. It is needed when the engine backfires to prevent the backfire getting into the crankcase.
To see that I am correct, take the PVC hose off the manifold and blow into it. Don't forget to have a beer in hand to get rid of all the oil and gas flavor! Or you can use a mitivac if you are faint of heart. If the PVC valve is functioning correctly no air will go into the crankcase. If it does, replace the PVC valve.
You also may have the same concern with the power brake booster. It also has a check valve that will prevent boost from getting in.
The only one I am not sure of is the EGR and Vapor canister.
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
Re: PCV boost question (Flame Red)
Ok, so the consensus seems to be disconnect the pipe going from the pass valve cover to the TB, put breather on the valve cover side and plug the TB side. And the PCV valve should do it's job and be ok as is.
Any contradictions???? :confused: If not that's what I'll be doing tonight
Any contradictions???? :confused: If not that's what I'll be doing tonight
Drifting
Joined: Feb 2002
Posts: 1,937
Likes: 2
From: Arvada CO
Re: PCV boost question (mn_vette)
ok wait...i thought you had to get breathers for the valve covers because you dont want all that pressure in the crank case because that pressure has to go some where?
Le Mans Master
Joined: Apr 2000
Posts: 6,341
Likes: 1
From: Shelton CT
Re: PCV boost question (Flame Red)
I think I have the answer to this. I put a beather on the pass side valve cover and left the PVC connected to the manifold. Plugged the port on the throttle body.
When positive boost is obtained, the PVC valve closes as to not let the boost leak into the crankcase. This is a builtin safety of the PVC system. It is needed when the engine backfires to prevent the backfire getting into the crankcase.
To see that I am correct, take the PVC hose off the manifold and blow into it. Don't forget to have a beer in hand to get rid of all the oil and gas flavor! Or you can use a mitivac if you are faint of heart. If the PVC valve is functioning correctly no air will go into the crankcase. If it does, replace the PVC valve.
You also may have the same concern with the power brake booster. It also has a check valve that will prevent boost from getting in.
The only one I am not sure of is the EGR and Vapor canister.
When positive boost is obtained, the PVC valve closes as to not let the boost leak into the crankcase. This is a builtin safety of the PVC system. It is needed when the engine backfires to prevent the backfire getting into the crankcase.
To see that I am correct, take the PVC hose off the manifold and blow into it. Don't forget to have a beer in hand to get rid of all the oil and gas flavor! Or you can use a mitivac if you are faint of heart. If the PVC valve is functioning correctly no air will go into the crankcase. If it does, replace the PVC valve.
You also may have the same concern with the power brake booster. It also has a check valve that will prevent boost from getting in.
The only one I am not sure of is the EGR and Vapor canister.
Drifting
Joined: Jan 2001
Posts: 1,669
Likes: 1
Re: PCV boost question (MrNuke)
Mine are disconteccted and I have an evacuation kit installed. It is also a good idea to use a zip tie on the vacuum lines you do have so you do not blow them off. I installed a check valve in the car vacuum so it would not damage lines in my dash and my AFR uses a #4 braided nylon line that has #4 AN connectors so it will not blow off under full boost.
Most kits do not come with it, but it is a good idea to have a blow off valve when you go from wot to closed throttle, that way you do not strain the impeller in the SC.
[Modified by snaketr, 9:37 AM 1/30/2003]
Most kits do not come with it, but it is a good idea to have a blow off valve when you go from wot to closed throttle, that way you do not strain the impeller in the SC.
[Modified by snaketr, 9:37 AM 1/30/2003]
Le Mans Master
Joined: May 1999
Posts: 6,517
Likes: 1,304
From: Windermere FL
Re: PCV boost question (krivera)
No, that is not correct. You want a breather there to supply air to the crankcase when the engine is operating with normal vacuum (no boost). so the PVC can suck in the fumes into the manifold.
If you don't have a breather, meaning you leave that connection from the throttle body to the pass side valve cover to supply air for the PVC, the boost will come out of the throttle body and pressurize your crank case. It is best to plug the output of the TB that fed air into the PVC system.
When you cap it off, it is a good idea to wire tie it. I have heard that people with large boost had these caps fly off!
If you don't have a breather, meaning you leave that connection from the throttle body to the pass side valve cover to supply air for the PVC, the boost will come out of the throttle body and pressurize your crank case. It is best to plug the output of the TB that fed air into the PVC system.
When you cap it off, it is a good idea to wire tie it. I have heard that people with large boost had these caps fly off!
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
Re: PCV boost question (Flame Red)
No, that is not correct. You want a breather there to supply air to the crankcase when the engine is operating with normal vacuum (no boost). so the PVC can suck in the fumes into the manifold.
If you don't have a breather, meaning you leave that connection from the throttle body to the pass side valve cover to supply air for the PVC, the boost will come out of the throttle body and pressurize your crank case. It is best to plug the output of the TB that fed air into the PVC system.
When you cap it off, it is a good idea to wire tie it. I have heard that people with large boost had these caps fly off!
If you don't have a breather, meaning you leave that connection from the throttle body to the pass side valve cover to supply air for the PVC, the boost will come out of the throttle body and pressurize your crank case. It is best to plug the output of the TB that fed air into the PVC system.
When you cap it off, it is a good idea to wire tie it. I have heard that people with large boost had these caps fly off!
Ok, so you are saying that I need to keep vaccume on that side of the valve cover? something like hooking it up to the airfilter, to keep the gasses flowing out of the crank case? perhaps I would be able to retrofit a second pcv valve in the tube to keep the stuff flowing in the right direction and keep the stock set up like that..........??????hmmmmm, time to think
[Modified by mn_vette, 4:57 PM 1/30/2003]
Le Mans Master
Joined: May 1999
Posts: 6,517
Likes: 1,304
From: Windermere FL
Re: PCV boost question (mn_vette)
MN,
ok, I'll try to make this clear. On the pass side valve cover put a breather filter. Remove the tube that went from the pass side valve cover to the throttle body. Plug (and wire tie) a cap on the throttle body where this tube went in.
Do nothing to the driver side (where the PVC is).
The manifold sucks (vacuum) from the PVC on the driver's side. The PVC will stop the boost from going into the crank (if the valve is good).
The tube on the pass side supplied air from the TB into the crankcase.
Hope that clears it up.
ok, I'll try to make this clear. On the pass side valve cover put a breather filter. Remove the tube that went from the pass side valve cover to the throttle body. Plug (and wire tie) a cap on the throttle body where this tube went in.
Do nothing to the driver side (where the PVC is).
The manifold sucks (vacuum) from the PVC on the driver's side. The PVC will stop the boost from going into the crank (if the valve is good).
The tube on the pass side supplied air from the TB into the crankcase.
Hope that clears it up.
Drifting
Joined: Feb 2002
Posts: 1,937
Likes: 2
From: Arvada CO
Re: PCV boost question (Flame Red)
ok lets make this simple
1.TB tube on passanger side cap off with wire tie or something
2. valve cover passanger side baby K&N filter
3. valve cover drivers side baby K&N Filter
4. intake manifold cap off with wire tie or something.
purpose to relieve pressure in the crankcase and baby K&N to filter the air? there are some states that need emissions stuff and there is stuff from jegs or summit you can get parts for that emissions
1.TB tube on passanger side cap off with wire tie or something
2. valve cover passanger side baby K&N filter
3. valve cover drivers side baby K&N Filter
4. intake manifold cap off with wire tie or something.
purpose to relieve pressure in the crankcase and baby K&N to filter the air? there are some states that need emissions stuff and there is stuff from jegs or summit you can get parts for that emissions