What would the ill affects of this be (PCV mods)
Thread Starter
TECH Senior Member
Joined: Nov 2001
Posts: 10,341
Likes: 1
What would the ill affects of this be (PCV mods) I know everyone is complaining about excessive PCV oil consumption. Could someone to this do you think?
block off the fresh air line from the T-body to the valve cover.
Remove the PCV line from the manifold and plug it.
extend and run the PCV line WITHOUT a PCV valve in it to within one inch of the airfilter.
If you did this the PCV would vent to atmosphere and the fumes would get sucked into the airfilter on the way to the motor. There wouldnt be a vac leak and you wouldn't have to worry about fumes in the car or oil dripping from a valve cover breather on your headers. The vapor from the PCV would get sucked in through the airfilter and not cause a stink. Is there something I am missing here? After WOT and the throttle closes wouldnt the PCV just vent to atmosphere but still get the vapor sucked into the airfilter?
You would have to clean your filter a little more frequently but you wouldnt have to worry about oil consumption. What am I missing or would this work?
Chris.
block off the fresh air line from the T-body to the valve cover.
Remove the PCV line from the manifold and plug it.
extend and run the PCV line WITHOUT a PCV valve in it to within one inch of the airfilter.
If you did this the PCV would vent to atmosphere and the fumes would get sucked into the airfilter on the way to the motor. There wouldnt be a vac leak and you wouldn't have to worry about fumes in the car or oil dripping from a valve cover breather on your headers. The vapor from the PCV would get sucked in through the airfilter and not cause a stink. Is there something I am missing here? After WOT and the throttle closes wouldnt the PCV just vent to atmosphere but still get the vapor sucked into the airfilter?
You would have to clean your filter a little more frequently but you wouldnt have to worry about oil consumption. What am I missing or would this work?
Chris.
Thread Starter
TECH Senior Member
Joined: Nov 2001
Posts: 10,341
Likes: 1
Re: What would the ill affects of this be (PCV mods) You got it <img src="gr_stretch.gif" border="0">
Instead of the check valve you relocate the line to the filter <img src="gr_stretch.gif" border="0">
hee hee
Chris
Instead of the check valve you relocate the line to the filter <img src="gr_stretch.gif" border="0">
hee hee
Chris
Joined: Nov 2001
Posts: 34,663
Likes: 2,596
From: Schiller Park, ILL Member: #317
Re: What would the ill affects of this be (PCV mods) It’s my understanding that the PCV system (when using a regular PCV valve in the stock system) does not operate under WOT conditions. If this is correct (correct me if I’m wrong), you would now be introducing hot PCV vapors to the motor under WOT that weren’t previously there, and in effect slightly raising your Intake Air Temp, correct? Plus, I don’t know if you’d get enough vacuum to simulate a stock operating PCV system. IMO, better to just use a Metco breather in the oil fil cap in addition to a stock PCV system w/ the vertical mod. I don’t get any leakage from that set up, and it seemed to stop my oil consumption too.
Thread Starter
TECH Senior Member
Joined: Nov 2001
Posts: 10,341
Likes: 1
Re: What would the ill affects of this be (PCV mods) Only prob with that setup is that there is a vac leak introduced in the system (Fresh air line is still attached and the PCV is still attached.) However the filter on the oil cap introduces a vac leak, creating an open system.
The only reason PCVs arent vented to atmosphere is for emissions and the odor of PCV vapor under the hood. If the PCV valve was removed and the open lines were routed to the bottom of the airfilter, then the odors would get sucked into the airfilter. The IATs wouldnt rise considerably when you consider the amount of air being sucked into the motor. There wouldn't be any risk of blowing gaskets as both valvecovers are vented, joined by the Y and placed within one inch of the airfilter (which would suck up the fumes.) With the fresh air line closed off there isnt any worry of introducing a vac leak or unmetered air entering the motor.
Am I missing something in my logic?
Cheers,
Chris
The only reason PCVs arent vented to atmosphere is for emissions and the odor of PCV vapor under the hood. If the PCV valve was removed and the open lines were routed to the bottom of the airfilter, then the odors would get sucked into the airfilter. The IATs wouldnt rise considerably when you consider the amount of air being sucked into the motor. There wouldn't be any risk of blowing gaskets as both valvecovers are vented, joined by the Y and placed within one inch of the airfilter (which would suck up the fumes.) With the fresh air line closed off there isnt any worry of introducing a vac leak or unmetered air entering the motor.
Am I missing something in my logic?
Cheers,
Chris
Joined: Nov 2001
Posts: 34,663
Likes: 2,596
From: Schiller Park, ILL Member: #317
Re: What would the ill affects of this be (PCV mods) I’ll bet it would effect my IATs more then most, since my hood is sealed to the air box and I’m ONLY getting cool outside air right now.
I see what you mean about the vac leak, but I don’t seem to have one <img src="images/icons/confused.gif" border="0"> If there were a vac leak (like when the PCV is disconnected) due to the Metco, then my Ltrims should be at 25% at idle, correct? They aren’t though...they are perfectly normal (0 to 4). I don’t think you’re introducing any significant amount of unmetered air by having a breather in place of the oil fill cap and still keeping a fully intact PCV system? Maybe I’m wrong? <img src="images/icons/confused.gif" border="0">
I see what you mean about the vac leak, but I don’t seem to have one <img src="images/icons/confused.gif" border="0"> If there were a vac leak (like when the PCV is disconnected) due to the Metco, then my Ltrims should be at 25% at idle, correct? They aren’t though...they are perfectly normal (0 to 4). I don’t think you’re introducing any significant amount of unmetered air by having a breather in place of the oil fill cap and still keeping a fully intact PCV system? Maybe I’m wrong? <img src="images/icons/confused.gif" border="0">
TECH Addict
Joined: Dec 2001
Posts: 2,298
Likes: 2
From: new england
Re: What would the ill affects of this be (PCV mods) CHRIS, your idea is perfect for wot, and hi rpm.
There wouldnt be any vacuum developed by your system, at part throttle it would not apply the vacuum to crankcase that ring package was engineered for, that doesnt mean it wouldnt be acceptable worth trying IMO. BUT remember pcv contributes to idle speed (its a bypass of air around throttle not thru it) and this would require opening throttle more to get same idle speed.
There wouldnt be any vacuum developed by your system, at part throttle it would not apply the vacuum to crankcase that ring package was engineered for, that doesnt mean it wouldnt be acceptable worth trying IMO. BUT remember pcv contributes to idle speed (its a bypass of air around throttle not thru it) and this would require opening throttle more to get same idle speed.
Trending Topics
Thread Starter
TECH Senior Member
Joined: Nov 2001
Posts: 10,341
Likes: 1
Re: What would the ill affects of this be (PCV mods) ahh I see <img src="gr_stretch.gif" border="0">
So the rings are affected by part throttle vaccum from the PCV? That is VERY interesting!
What would the possible ill affects be?
Thanks again,
Chris
So the rings are affected by part throttle vaccum from the PCV? That is VERY interesting!
What would the possible ill affects be?
Thanks again,
Chris
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'
Brett Foote
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?
Pouria Savadkouei
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Re: What would the ill affects of this be (PCV mods) Open pcv line like that will cause the car to have a higher idle from the vacuum leak. I think the L-trims will be higher as well.
I have messed with some of that stuff. Anytime I have run with an open pcv line my idle gets a little more ragged and goes up at least 100 rpms.
I have messed with some of that stuff. Anytime I have run with an open pcv line my idle gets a little more ragged and goes up at least 100 rpms.
TECH Addict
Joined: Dec 2001
Posts: 2,298
Likes: 2
From: new england
Re: What would the ill affects of this be (PCV mods) CHRIS, when pressure differential between comb. chamber and crankcase(above and below rings) is great, cylinder pressure hi from wide throttle opening keeps rings seated, but with less difference(part throttle) radial tension on rings plays a role and vacuum in crankcase from closed pcv system help with the rest of the work. What could happen is you could lose oil scraping efficiency of rings , and increase oil consumption.
Re: What would the ill affects of this be (PCV mods) What I am running right now is similar. I run a hose from the driver's cover to a "T" and connect the hose from the rear tube on the passenger side, the use a check valve from there to the lower hole on the intake (behind the TB on the pass side). I use a 3-inch K&N filter on the front valve cover tube on the pass side. This allows fresh air into the system. I was told the system needs to have a fresh air source.
TECH Addict
Joined: Dec 2001
Posts: 2,298
Likes: 2
From: new england
Re: What would the ill affects of this be (PCV mods) By the way, pcv does flow at WOT. Most street engines pull some manifold vacuum at wide open throttle(because induction components wont satisfy total engine airflow requirements)
PCV's flow at low vacuum conditions, they close at hi vacuum and hi pressure to keep a intake backfire from exploding crankcase fumes! <img src="gr_eek2.gif" border="0">
PCV's flow at low vacuum conditions, they close at hi vacuum and hi pressure to keep a intake backfire from exploding crankcase fumes! <img src="gr_eek2.gif" border="0">
TECH Addict
Joined: Dec 2001
Posts: 2,298
Likes: 2
From: new england
Re: What would the ill affects of this be (PCV mods) It sounds like your check valve replaced the pcv,
if so how do you keep or know what flow rate to use, in other words did this raise your idle way up? Also what keeps this from sucking oil into lower port?
if so how do you keep or know what flow rate to use, in other words did this raise your idle way up? Also what keeps this from sucking oil into lower port?
TECH Addict
Joined: Dec 2001
Posts: 2,298
Likes: 2
From: new england
Re: What would the ill affects of this be (PCV mods) Not to get off the subject but I know having hi vacuum in crankcase is worth power, COmp and Pro Stock motors have run modified air pumps to pull a hi vacuum in motors. They worked so well some people had wrist pin siezing problems from oil lube being drawn off of them from this vacuum!
LS1 would benefit from this but the more RPM's the more there would be to gain. Food for thought. <img src="graemlins/burnout.gif" border="0" alt="[Burnout]" />
LS1 would benefit from this but the more RPM's the more there would be to gain. Food for thought. <img src="graemlins/burnout.gif" border="0" alt="[Burnout]" />
Joined: Nov 2001
Posts: 34,663
Likes: 2,596
From: Schiller Park, ILL Member: #317
Re: What would the ill affects of this be (PCV mods) [quote]Originally posted by Grinch(supra killa):
<strong>can some explain the breather in the oil fill cap mod?</strong><hr></blockquote>
A company called Metco (I can’t remember their website though, it’s something like metco-inc.com or something) makes a breather that has a screw in base that goes in place of the oil fill cap. Then a breather pops into that base. This allows you to retain a full factory PCV system, but still vent pressure into the atmosphere enough that the PCV doesn’t seem to suck oil into the intake anymore. I don’t know if the PCV is doing anything at this point, but what’s the lesser of the two evils, oil fouled intake, valves, piston tops, etc., or less PCV operation? I just don’t know, so I’ve been going back a fourth on this setup. But every time I put the breather back in my oil consumption goes away.
<strong>can some explain the breather in the oil fill cap mod?</strong><hr></blockquote>
A company called Metco (I can’t remember their website though, it’s something like metco-inc.com or something) makes a breather that has a screw in base that goes in place of the oil fill cap. Then a breather pops into that base. This allows you to retain a full factory PCV system, but still vent pressure into the atmosphere enough that the PCV doesn’t seem to suck oil into the intake anymore. I don’t know if the PCV is doing anything at this point, but what’s the lesser of the two evils, oil fouled intake, valves, piston tops, etc., or less PCV operation? I just don’t know, so I’ve been going back a fourth on this setup. But every time I put the breather back in my oil consumption goes away.
