confused on vacuum ports
Thread Starter
Joined: Jun 2005
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From: Los Angeles, CA (Burbank)
confused on vacuum ports sorry guys, i've looked at the HVAC diagram and I'm confused...I put an LS1 (98) into an LT1 body, and I got the EGR/AIR deleted from the PCM. As of now there are no vacuum hoses connected. I was wondering what you guys recommend as the best way to hook up the vacuum ports. I am assuming that I circled all the ports in the pics below, but if I'm wrong, please correct me!
I guess another way of asking is...where do these lines go, or what is the best way to hook them up or plug them, if I have EGR/AIR deleted, and A/C deleted?
Thanks again for any help; I am getting VERY close to starting this car up finally!!
I guess another way of asking is...where do these lines go, or what is the best way to hook them up or plug them, if I have EGR/AIR deleted, and A/C deleted?
Thanks again for any help; I am getting VERY close to starting this car up finally!!
#1 is a vacumn port for the Brake booster.
#2 is the PCV port, not vacumn.
#3 is the Fresh air into (for the PCV system) which connects to #5
#4 is for the EVAP (I think), I use to on mine for Vacumn source... it act more like ported vacumn as compared to straight manifold vacumn.
#5 Fresh air intake from #3 (see above)
#6 not use.. ask someone with a Fast Intake. but it looks like a manifold vacumn port. Maybe used for MAP ?
#2 is the PCV port, not vacumn.
#3 is the Fresh air into (for the PCV system) which connects to #5
#4 is for the EVAP (I think), I use to on mine for Vacumn source... it act more like ported vacumn as compared to straight manifold vacumn.
#5 Fresh air intake from #3 (see above)
#6 not use.. ask someone with a Fast Intake. but it looks like a manifold vacumn port. Maybe used for MAP ?
Thread Starter
Joined: Jun 2005
Posts: 755
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From: Los Angeles, CA (Burbank)
Gotcha, ok, so then, can I do this, will this work:
#1 is a vacumn port for the Brake booster. --> Connect to brake booster.
#2 is the PCV port, not vacumn. --> Can I put a filter/breather on here?
#3 is the Fresh air into (for the PCV system) which connects to #5 --> Run a rubber hose to #5.
#4 is for the EVAP (I think), I use to on mine for Vacumn source... it act more like ported vacumn as compared to straight manifold vacumn. --> Plug with a vacuum plug.
#5 Fresh air intake from #3 (see above) --> Rubber hose to #3.
#6 not use.. ask someone with a Fast Intake. but it looks like a manifold vacumn port. Maybe used for MAP? --> Plug with vacuum plug.
#1 is a vacumn port for the Brake booster. --> Connect to brake booster.
#2 is the PCV port, not vacumn. --> Can I put a filter/breather on here?
#3 is the Fresh air into (for the PCV system) which connects to #5 --> Run a rubber hose to #5.
#4 is for the EVAP (I think), I use to on mine for Vacumn source... it act more like ported vacumn as compared to straight manifold vacumn. --> Plug with a vacuum plug.
#5 Fresh air intake from #3 (see above) --> Rubber hose to #3.
#6 not use.. ask someone with a Fast Intake. but it looks like a manifold vacumn port. Maybe used for MAP? --> Plug with vacuum plug.
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Verdad Gallardo Thread Starter
Joined: Jun 2005
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From: Los Angeles, CA (Burbank)
From what I understand, the PCV system is designed to relieve crankcase pressure, correct? If the LS1 system relieves that pressure by the port on the back of the driver's side valve cover (#2 in the pics above), is there something wrong with putting a breather on there?
Does it reroute the pressure somewhere? On old school motors they reroute to the intake manifold I believe, but lots of old school muscle car guys use vents on the valve cover instead, that's why I was wondering if that would work.
Does it reroute the pressure somewhere? On old school motors they reroute to the intake manifold I believe, but lots of old school muscle car guys use vents on the valve cover instead, that's why I was wondering if that would work.
Thread Starter
Joined: Jun 2005
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From: Los Angeles, CA (Burbank)
Ok, I found the PCV routing for a 98:
unfortunately, on my passenger side valve cover, there is no port at the rear for the pcv (for return air). wtf:
unfortunately, on my passenger side valve cover, there is no port at the rear for the pcv (for return air). wtf:
The problem that I see, is the same with my setup. The diagram shown below has 1 fresh air inlet on the intake and the other fresh air inlet of the PCV or Crank is suppose to be on the Throttle body. I'm running a Truck DBW throttle body and there is no fresh air inlet.
Thread Starter
Joined: Jun 2005
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From: Los Angeles, CA (Burbank)
If you use the LS6 (convert to it). you will not need the ports on the valve covers. The PCV will be pulling from a port the Lifter Valley cover.
Old School, new school. Doesn't matter, the basic PCV system is still the same, just designed to meet the phyically limitation of the different engines and where ports can be placed or found. its as simple as 1, 2, 3.... old or new, this is all it takes.
1) Vacumn source (either manifold or base of intake, can be a carb or Throttle Body),
2) ports to draw the air and vapors from the inside of the engine (can be on valve covers, lifter valley, oil pan, etc).
3) a oil restrictor to seperate the vapors from the oil and to block the oil from being pulled into the intake. (PCV Valve or baffles below the port being drawn from, or even a Catch Can inline).
As said, many have just used breather. That can work, but there are pros and cons to using just breathers or when combined with a PCV system and breather together. (I would not recommend that myself for a street car that is smogged). Sugggest you research this subject.
Breathers will only allow internal pressure to be pushed out the breather (oil along with it caused by blow by). If the breather over time, doesn't do the job, blown oil seals can result (I say can, but not always). Neg pressue can be a good thing, If you check some of the pro or mod cars, they use a vacumn pump to create neg pressure, it also helps to seal the piston rings.
As with everyone, they have there own option and different results from the same setup. find out what works for you and what doesn't. Research will help direct you on what you thing is a good starting point or direction.
Old School, new school. Doesn't matter, the basic PCV system is still the same, just designed to meet the phyically limitation of the different engines and where ports can be placed or found. its as simple as 1, 2, 3.... old or new, this is all it takes.
1) Vacumn source (either manifold or base of intake, can be a carb or Throttle Body),
2) ports to draw the air and vapors from the inside of the engine (can be on valve covers, lifter valley, oil pan, etc).
3) a oil restrictor to seperate the vapors from the oil and to block the oil from being pulled into the intake. (PCV Valve or baffles below the port being drawn from, or even a Catch Can inline).
As said, many have just used breather. That can work, but there are pros and cons to using just breathers or when combined with a PCV system and breather together. (I would not recommend that myself for a street car that is smogged). Sugggest you research this subject.
Breathers will only allow internal pressure to be pushed out the breather (oil along with it caused by blow by). If the breather over time, doesn't do the job, blown oil seals can result (I say can, but not always). Neg pressue can be a good thing, If you check some of the pro or mod cars, they use a vacumn pump to create neg pressure, it also helps to seal the piston rings.
As with everyone, they have there own option and different results from the same setup. find out what works for you and what doesn't. Research will help direct you on what you thing is a good starting point or direction.
