PCV Confusion
PCV Confusion I think I've read just about all of the PCV threads on this site and I'm more confused than before. Everybody has differing opinions and suggestions when it comes to FI and PCVs.
I understand how the stock system works. It's a closed system with the two ports on the rear of the valve covers tied together running to the PCV valve and then to the intake manifold. This sucks the gasses out of the crankcase under vacuum.
The hose connected to the front of the passenger's side valve cover routes to the throttle body. Fresh air metered by the MAF is drawn into the crankcase there as it is at atmospheric pressure.
Am I correct so far?
Here's how I plan to run my PCV for FI.
1. Run a check valve between the manifold and PCV to prevent boosting the crankcase.
2. Block the throttle body port and run a hose from the front of the valve cover to a catch can.
3. The other port on the catch will go to the turbo on the intake side after the filter. The way that I understand this is that there will be vacuum there under boost. Is that correct?
There will be no breather on the catch can. I've read that this is a vacuum leak. Can someone help here.
All of the above vents the crank case, but I'll need to have a breather on a valve cover to let air back in. My question here is, doesn't that make the PCV an open system? Now unmetered air is being drawn into the PCV system. Does this even matter?
So many questions I know, but it seems as if everyone has differing setups and opinions. Also, I don't plan on going to an LS6 valley cover if at all possible.
I understand how the stock system works. It's a closed system with the two ports on the rear of the valve covers tied together running to the PCV valve and then to the intake manifold. This sucks the gasses out of the crankcase under vacuum.
The hose connected to the front of the passenger's side valve cover routes to the throttle body. Fresh air metered by the MAF is drawn into the crankcase there as it is at atmospheric pressure.
Am I correct so far?
Here's how I plan to run my PCV for FI.
1. Run a check valve between the manifold and PCV to prevent boosting the crankcase.
2. Block the throttle body port and run a hose from the front of the valve cover to a catch can.
3. The other port on the catch will go to the turbo on the intake side after the filter. The way that I understand this is that there will be vacuum there under boost. Is that correct?
There will be no breather on the catch can. I've read that this is a vacuum leak. Can someone help here.
All of the above vents the crank case, but I'll need to have a breather on a valve cover to let air back in. My question here is, doesn't that make the PCV an open system? Now unmetered air is being drawn into the PCV system. Does this even matter?
So many questions I know, but it seems as if everyone has differing setups and opinions. Also, I don't plan on going to an LS6 valley cover if at all possible.
I think the way it works is when your crankcase is filled with gases its pushing outwards so there wouldn't be much air coming in through the valve cover filter.. The line to the turbo filter would first suck all the internal gases out and then if it was sucking more than the amount of gases in the crankcase it would suck in the fresh air rather than sucking out a seal somewhere..
I assume that if the vc filters are restrictive enough that's the amount of air sucked in from the turbo is still able to create negative pressure...
I'm wondering tho..
I'm looking at doing this setup as well and if I ran the line to the turbo would I still need the line going to the intake which closes under boost via a check valve? Or would the line to the turbo filter be sufficient.. Or is it that it needs more vacuum at idle?
Also I know I would need a pcv, catch can and check valve for the line front the back of the valve covers to the intake..
I also assume I need a catch can in the line to the filter of the turbo to stop oil but would I need a pcv here as well? That way when the turbo is sucking at high rpms it doesn't pull too much vacuum?
I plan on running braided lines from the valve covers to the turbo.. Is there a pcv that has npt fittings that anyone knows of? Or would I even need it.
I assume that if the vc filters are restrictive enough that's the amount of air sucked in from the turbo is still able to create negative pressure...
I'm wondering tho..
I'm looking at doing this setup as well and if I ran the line to the turbo would I still need the line going to the intake which closes under boost via a check valve? Or would the line to the turbo filter be sufficient.. Or is it that it needs more vacuum at idle?
Also I know I would need a pcv, catch can and check valve for the line front the back of the valve covers to the intake..
I also assume I need a catch can in the line to the filter of the turbo to stop oil but would I need a pcv here as well? That way when the turbo is sucking at high rpms it doesn't pull too much vacuum?
I plan on running braided lines from the valve covers to the turbo.. Is there a pcv that has npt fittings that anyone knows of? Or would I even need it.
btw.. I tapped an extra spot in my oil pan so that I could read the pressure to vacuum here.. At least I think this is possible..
What should I have as far as vacuum at idle and what at wot throttle?
What should I have as far as vacuum at idle and what at wot throttle?
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
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!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
i run check valves in both hoses off each valve cover which T together and go to a catch can,the other port on the catch can runs to the inlet on the turbo,and i run a breather where the oil fill is
the TB is plugged the manifold is now my boost gauge reference source.do a search for a PCV thread with me and Mighty Mouse talking about it i posted a like.i think theyre made by usplastic
I plugged off all of my port's and vented to atmosphere.Big filter where you put the oil in and a small one on the port beside it on the valve cover. I had pcv problem's before but not anymore.You just have to change the oil sooner. 
Here's how I set mine up.
- stock pcv lines -> catch can
- catch can -> pcv valve
- pcv valve -> chk valve
- chk valve -> intake
The check valve prevents boosting the crank case via PCV when in boost.
I also have a line from the pass valve cover to the inlet hat, which positively vents the crankcase when in boost.
Rob (Bad30th)
- stock pcv lines -> catch can
- catch can -> pcv valve
- pcv valve -> chk valve
- chk valve -> intake
The check valve prevents boosting the crank case via PCV when in boost.
I also have a line from the pass valve cover to the inlet hat, which positively vents the crankcase when in boost.
Rob (Bad30th)
I feel like somebody has a new setup every day.
Im using a vac manifold coming out of brake booster for my boost guage so should I just plug the mani port?
the manifold is now my boost gauge reference source
Originally Posted by JAvenger007
I feel like somebody has a new setup every day.
Im using a vac manifold coming out of brake booster for my boost guage so should I just plug the mani port?
Im using a vac manifold coming out of brake booster for my boost guage so should I just plug the mani port?
