Do you need a PCV valve?
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Joined: Sep 2008
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From: Mississippi
Do you need a PCV valve? I was just checking everything on my car that I bought 2 months ago and noticed it didn't have a PVC valve stuck in the intake plenum. I was wondering if anybody knew if you had to have one in there. Would it affect performance?
Yes and NO. Yes you need one because otherwise the crankcase pressure will not be relieved and in the oil will form a milky white gooey substance. You will see if you pull a valvecover that it may be forming already and be stuck to your valve cover.
If you are not worried about emission you can get a Pan-U-Vac system which will do a better job and increase your power slightly. It replaces the valve cover breather and ties into the exhaust to create a vaccuum. It is available from Milodon.
Hope that helps.
If you are not worried about emission you can get a Pan-U-Vac system which will do a better job and increase your power slightly. It replaces the valve cover breather and ties into the exhaust to create a vaccuum. It is available from Milodon.
Hope that helps.
I looked into these, after talking to several people on other sties and locally, I learned they're intended more for cars with open headers or exhaust w/ no mufflers that run high rpm's. I was told a muffler would probably restrict the exhaust just enought to not create a strong enough vaccum for the system to work properly.
https://ls1tech.com/forums/drag-racing-tech/997485-pcv-question.html
Not much of a response here but there was on racingjunk.com.
I tried to post a link to the post but it wants you to log in as a member before viewing so I removed it.
Summit, Jegs and Moroso all sell em. I'm going to just keep my inline filter, if you try the crancase evac. system keep us posted. Hope this helps!
https://ls1tech.com/forums/drag-racing-tech/997485-pcv-question.html
Not much of a response here but there was on racingjunk.com.
I tried to post a link to the post but it wants you to log in as a member before viewing so I removed it.
Summit, Jegs and Moroso all sell em. I'm going to just keep my inline filter, if you try the crancase evac. system keep us posted. Hope this helps!
How much vacuum is needed for it to actually work... do you have to do both VC's?
I only ask because could the breather/covers you get at shops locally that do not vent but rather let you tie back into the engine vacuum not cause the same effect?
I am also curious as to the extent of the oil thats pulled through the VC or VC's that shows in the exhaust...
I only ask because could the breather/covers you get at shops locally that do not vent but rather let you tie back into the engine vacuum not cause the same effect?
I am also curious as to the extent of the oil thats pulled through the VC or VC's that shows in the exhaust...
The way I understand it the angle of the tubes welded into the header collectors and the pulses of the exhaust create a vaccum inside the lines. There is a check valve in each line and then the breathers in each valve cover. When you are at WOT the vaccum puts negative pressure inside the crankcase promoting ring seal and freeing up HP. I don't think this will be effective on a street car with mufflers spending much of it's time at low to mid rpm's.
Cross: The idea you mentioned in your second sentence sounds like the same principal applied in the current PCV system. I'm sure the amount of oil burned into the exhaust is minimal, after 10-12 passes and about 50 street miles I've accumulated about 1 tsp of oil in my filter. I would think most cars using this system are going to be track only cars with fluid checks between rounds.
Cross: The idea you mentioned in your second sentence sounds like the same principal applied in the current PCV system. I'm sure the amount of oil burned into the exhaust is minimal, after 10-12 passes and about 50 street miles I've accumulated about 1 tsp of oil in my filter. I would think most cars using this system are going to be track only cars with fluid checks between rounds.
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Joined: Sep 2008
Posts: 8
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From: Mississippi
Cool , I'll check into it and let you know. I have headers and was thinking of getting a cutout . Would it work with that setup or would have to cut it completely out before the y-pipe.
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I would imagine it would work with an open Y-pipe at higher rpm. It's the low rpm or idle time as a street car that worried me. I don't know if the exhaust air is pulsing fast enough to hold a vaccum. The race cars using this system only idle in the staging lanes and then back to the pitts so crankcase pressure and tempature wouldn't be a big issue, not so on a street car. I would think this would also work well on an autocross car too. I'm not an engine expert so I'm not sure how important keeping a vaccum is at low rpm but I figured it's there for a reason it's there, and I've got to much $ in my engine to risk it for a few HP!
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From: Decatur, TN (N-W of Athens)
Why don't you guys just turn your AIR pump into this? >_>
Make a catch can to filter out any oil that would be sucked up into the AIR pump, and then presto!
Make a catch can to filter out any oil that would be sucked up into the AIR pump, and then presto!
thinking about it, muffler or not, with the velocity of air through the exhaust stream, if you introduced a small pipe into it, its going to create a venturi effect. either way, if introduced properly, it will have low pressure area which will pull it out... i can draw an attachment on paint, WARNING... it will be ugly
TECH Senior Member
iTrader: (3)
Joined: Oct 2006
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From: Decatur, TN (N-W of Athens)
thinking about it, muffler or not, with the velocity of air through the exhaust stream, if you introduced a small pipe into it, its going to create a venturi effect. either way, if introduced properly, it will have low pressure area which will pull it out... i can draw an attachment on paint, WARNING... it will be ugly
I already understand what you mean (even before your explanation). I'm thinking it's not venturi effect though... but I could easily be wrong! I don't understand fluid dynamic, or anything on that level of mathematics or physics 
Still, what you say should easily be possible if the crank case atmosphere isn't thicker than that of the exhaust gas. Or is that assumption wrong and it wouldn't matter due to the speed of the exhaust gas and the amount of suction it would create?
https://ls1tech.com/forums/western-classifieds/1006106-demodding-many-lt1-performace-parts.html
You can see a pic of the Milodon Pan U Vac system here. I am selling mine Instead of using it. I am parting out the engine instead. I had to wait weeks before getting this as I don't think summit stocks it. Also have a cutout for sale.
You can see a pic of the Milodon Pan U Vac system here. I am selling mine Instead of using it. I am parting out the engine instead. I had to wait weeks before getting this as I don't think summit stocks it. Also have a cutout for sale.
I don't see the OP having nitrous or a blower, so just leave the damn PCV alone.
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Joined: Jan 2008
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From: Gladstone, Queensland, Australia
I have used pan vacs before, They suck like crazy even at low rpm. I used them in street driven cars with mufflers and they pull heaps of vacuum at all rpm, Just start the engine let it idle pull the vac line off and you will here massive suction. Just make sure u block everything up, no breathers etc so it will pull a decent vacuum. They dont work as good as a vac pump but will out do a pcv system.
