pcv removal idea...

[dnhieu]

alright yesterday i did a boost leak test and it appears my pcv valve is bad. i did alot of research and i came up with two choices. i can 1. remove it or 2. keep it. well if i keep it 99.99999999% of the crap you buy at the auto parts store is going to allow air past it under boost. well under further research i found that only 9-10 pcv valves from the STEALER ship work.

so i think im going to remove it. okay this is the idea i have. im going to make my own oil catch can with 3 nipples on it and no filter on top. im going to route all comming out from the valve cover to the oil catch can. then run a third on to the oil catch can to the air intake.

the question i have is there going to be a problem from always drawing air out of the air valve cover? here is a picture i made, please excuse my drawing. i am no expert by any means...

thanks in advance
david

 

[1stGenRocks]

Thats the right way. You can buy a can or theres a good tech article about making one on here. The only reason the stock setup has a valve is to keep from letting boost into the valve cover, but we all know how well that works...

 

[dnhieu]

am i going to run into any problems with always drawing vacumme outta the valve cover tho?

 

[GVR4592]

This link might help answer some of your questions
http://www.roadraceengineering.com/instructions/catchcaninstructions.htm

 

[Bestwestranger]

The only problems I could see because of the higher crank case pressure would be...

1. Blowing the dip stick out.
2. Blowing oil into the combustion chamber if the rings aren't in the best of shape, or possibly blowing seals.


What you may want to try before you ditch the pcv is to clean it out. Pull it off and soak it in carb cleaner to clean the garbage out of it. Pretty much all that is in there anyway is a check ball and spring...

 

[Turbocharged]

Go buy an OEM pcv valve. They are a little more pricey but they are the only valve that I have found that doesnt leak.

The setup you are considering will not work. Even if you made vacuum before the turbo (which you dont) you still need to have a way for air to actually circulate through; the crankcase will not be ventilated

 

[No_Skillz]

Go buy an OEM pcv valve. They are a little more pricey but they are the only valve that I have found that doesnt leak.

The setup you are considering will not work. Even if you made vacuum before the turbo (which you dont) you still need to have a way for air to actually circulate through; the crankcase will not be ventilated

I agree. You have your intake making a vacuum, but no air would actually circulate since you do not have another source.

 

[TicEagle]

I have this setup and everything is ok. I use a 1/8npt fitting to remplace the pcv valve.

 

[dnhieu]

i dont understand. this is pretty much the same way the stock set up would be. the pcv valve closes under boost. then under vacumme it sucks air out of the head. so i will be sucking air outta the head via the intake pipe and under boost i dont have to worry about ANY air getting into the head...

can you guys further argue my point so i can understand yours better. i am no way trying to argue im just telling you the way i am currently seeing it in my mind...

i made the oil catch can today and boost leak tested the car. looks like im still getting a little bit of blow by buy NOT nearly as much i was getting with the broken pcv valve in place. i also got a little more vacumme because i fixed the boost leak at the pcv valve. while driving it feels sluggish in vacumme but under boost conditions it feels really smooth...

 

[No_Skillz]

When you are boosting, you will have little problems since the PCV is closed and the system therefore resembles the stock setup. However, at idle or anything under boost, the VC breather and the PCV valve serve as ventilation for the crankcase, with negative pressure from the PCV(which connects to the intake manifold) and positive pressure from the VC breather (which connects to the intake). Therefore air tends to be sucked in from the VC breather and out the PCV valve, with oily blow feeding into your engine to be burned. With the way yours is set up, there is no ventilation of the crank case during idle or under boost.

 

[Sivad87]

actually its should still work just fine but in a different way.

in the stock setup it sucks ait through a system. vac source sucks air from crankcase. then the crank case sucks air from the intake. making a nice ventilation system. keeping the crankcase free from pressure. (the whole point)

now in the way he has it set up, all that is happening instead of the pressure being sucked out, the pressure is making its way out on its own. (high pressure flows to low pressure )

so when you have a high pressure sorce in the crankcase it will naturally want to make its way to the low pressure source. therefore making its way through the catch can and into the intake track. so still doing the same job in a different way.

so it should work just fine, but then again i could be completely and utterly wrong so use the information as you wish

 

[dnhieu]

I just reread my previous post and i forgot to mention that i dont have a hole in my intake for the vacumme line to the intake. so its basically set up like taboo speeds race vacumme line set up. that explains the sluggishness under vacumme.

alright so in the "stock setup" a line runs from the valve cover to the intake. i will basically have a STOCK set up with air being sucked in through the intake. the only argument i have to this is that you can put your hand over the air filter and feel the air getting sucked in. if it doesnt help ill take it off and put the oil catch can between the intake and valve cover.....

 

[dnhieu]

actually its should still work just fine but in a different way.

in the stock setup it sucks ait through a system. vac source sucks air from crankcase. then the crank case sucks air from the intake. making a nice ventilation system. keeping the crankcase free from pressure. (the whole point)

now in the way he has it set up, all that is happening instead of the pressure being sucked out, the pressure is making its way out on its own. (high pressure flows to low pressure )

so when you have a high pressure sorce in the crankcase it will naturally want to make its way to the low pressure source. therefore making its way through the catch can and into the intake track. so still doing the same job in a different way.

so it should work just fine, but then again i could be completely and utterly wrong so use the information as you wish

HAHAHAHAHA i was thinking it would cause a vacumme through the intake but your explination works too.....

 

[Turbocharged]

When you are boosting, you will have little problems since the PCV is closed and the system therefore resembles the stock setup. However, at idle or anything under boost, the VC breather and the PCV valve serve as ventilation for the crankcase, with negative pressure from the PCV(which connects to the intake manifold) and positive pressure from the VC breather (which connects to the intake). Therefore air tends to be sucked in from the VC breather and out the PCV valve, with oily blow feeding into your engine to be burned. With the way yours is set up, there is no ventilation of the crank case during idle or under boost.

You are absolutely correct.

Imagine you have a closed container (crankcase). You attach a line to that container and apply a very small vacuum source to the line. Is the container ventilated? No. There needs to be a pressure gradient for there to be appreciable flow.

If you are basing your ventilation on the premise that you have positive crankcase pressure under boost, then you are assuming that you have piston ring blowby.

 

[Sivad87]

You are absolutely correct.

Imagine you have a closed container (crankcase). You attach a line to that container and apply a very small vacuum source to the line. Is the container ventilated? No. There needs to be a pressure gradient for there to be appreciable flow.

If you are basing your ventilation on the premise that you have positive crankcase pressure under boost, then you are assuming that you have piston ring blowby.

exactly, but we all know nothing is perfect so pressure does build up inside the crankcase.

think of it like you said, attach a line to a container. now press down on the lid and let go. that is more or less the way the crankcase is because nothing is perfect. if it was perfect you wouldnt need a PCV in the first place because the crankcase would allways contain the same volume of air.

also that shows that if the crankcase does build up pressure there is a way to relieve it. the line.

also, if you just took a container and put pressure on it lid would pop off from the pressure.

kinda resembles a certain little dipstick eh' that shows that there is pressure in the crankcase (sometimes, and on some cars) to be able to need to vent itself or a pressure gradient as you called it. now not every car is the same but the way he has it set up if there is any pressure in the crankcase it can vent itself. if there isnt any pressure then there would be no need for the system in the first place and everyone could just run without a PCV.

 

[dnhieu]

The way i see it this system should work better because i #1 just eliminated the pcv valve and #2 ill be pulling out twice as much crank pressure because ther are now 2 spots the crank pressure can be relieved from...

 

[Dream On]

I'm curious to know if this would work as well. This was my original plan for my car as well.

 

[Turbocharged]

You guys do whatever you want. Im sticking with the OEM valve and OEM setup. I have pressure tested to 20 psi with no leaks and it offers ventilation under vacuum conditions, not WOT conditions.

BTW, saying "pressure gradient" is just a simpler way of saying "high pressure to low pressure".

 

[No_Skillz]

Turbocharged and I are not talking about relief of crankcase pressure. As I have stated, when you are boosting or when you have pressure in the crankcase, what you have set up will work fine in terms of relieving that pressure.

What Turbocharged and I ARE arguing is that this setup provides no ventilation of the crankcase during idle or when you are not boosting.

 

[dnhieu]

no one is trying to argue with you guys. your probably right but im going to give this a try to see what happens. if it works ill inform everyone that it is possible to remove the pcv valve, if it doesnt looks like im headed to mitsubishi and ordering a new pcv valve....

 

[No_Skillz]

Sorry, when I say argue, I really mean "suggesting." You might not notice any real difference. This closest analogy would be like venting the BOV. You will only notice a difference if you really tune your vehicle.

 

[Sivad87]

Sorry, when I say argue, I really mean "suggesting." You might not notice any real difference. This closest analogy would be like venting the BOV. You will only notice a difference if you really tune your vehicle.

i get what you guys are saying. its just i guess different strokes for different folks.

even without a true ventalation system it would still accomplish the same goal

besides its not like this is one of those things that is going to save mankind if your crankcase can vent properly or not

 

[MyBeatGSX]

Turbocharged and I are not talking about relief of crankcase pressure. As I have stated, when you are boosting or when you have pressure in the crankcase, what you have set up will work fine in terms of relieving that pressure.

What Turbocharged and I ARE arguing is that this setup provides no ventilation of the crankcase during idle or when you are not boosting.

Yes it does. His setup is pointless in my opinion but will work just fine. The better option is the RRE/Taboo style with 2 lines running to a vented catch can and nothing to the intake. This is the setup I've been using and it works fine.

The pressure in the crank case will naturally vent out those lines with the Taboo style setup. I can take a video for you of my car at idle and the blow by gases coming out the breather on the can. That's normally crap that would get sent through the intake manifold.

With his setup, it'll do the same thing, but also be aided by vacuum in the intake tube. And don't tell me there's no vacuum in the intake tube. How do you think air gets drawn in through the air filter? Does it just fall into it? There's negative pressure before the turbo, and that will draw air out of the crankcase.

The only problem I see, is that after the crankcase is put under vacuum, there's no way to get air in. Its like leaving your PCV hooked up at idle and plugging the breather hose/filter. Its going to blow a seal or something to get air in. You need to run only one line to that can, and put a breather filter on the other end of the valve cover. That way as air is drawn out of the crank case, there will be something to replace it with, rather than just ever increasing vacuum. But IMO, running that hose to the intake is pointless unless you're emissions concious or something.

You CAN run all cars without a PCV. PCV's are for emissions. Its so that crank case crap and blowby gets burned and catalyzed rather than blown off into the open air. There's nothing wrong or harmful to the engine by just letting it vent itself. I even ran this by RRE and they agreed that it was actually better for the engine to be run without a PCV.

EDIT: My bad on the guy I quoted. I just disagreed with you and then agreed with you half way down. I thought you meant it wouldn't suck anything out.

 

[dnhieu]

the reason i want the vacumme line to run from the oil catch can to the intake tube is so air thats in the valve cover still has its vacumme source. right now i have it like you stated with a breater filter up top untill i figure some way to get a tab on the side of my intake pipe. right now it runs like ass unless im in boost. it could also be because i got a bad tune now from fixing a boost leak....

edit: another reason is so that when i get dsm link that air is still accounted for...

also this guys post ^^^^ is completly right about the air naturally comming out. i put my finger over the top (where the filter would go on the catch can) and it had a bunch of pressure behind it. this was when i boost leak tested it and while the car was at idle....

 

[jott5555]

the way we did it was we closed off and plugged both the pcv and breather hose.. then in the front of the valve cover drilled and tapped two 3/8th holes on each side then ran ss lines to a catch can... and made some small baffels on the inside of the vc to stop oil from spraying into the holes from the cam...

works perfect..