Trying header evac PCV... what to do with stock PCV (LT1)
06-11-2012, 06:29 PM
#1
Trying header evac PCV... what to do with stock PCV (LT1) Posting this here because the car will be FI soon and there seems to be more of an issue with the stock PCV and boosted cars.
I took the fresh air hose off the pass sign valve cover and ran it to my header - I did not test vacuum with a gauge but it was clearly trying to suck the red rag I was holding away from me
Since I don't have the fresh air hose, is the PCV going to help me at all during low RPM (where header evac is weakest)? Or should I just plug the whole thing?
I took the fresh air hose off the pass sign valve cover and ran it to my header - I did not test vacuum with a gauge but it was clearly trying to suck the red rag I was holding away from me
Since I don't have the fresh air hose, is the PCV going to help me at all during low RPM (where header evac is weakest)? Or should I just plug the whole thing? 
06-11-2012, 07:21 PM
#2
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i actually used a series of check valves to keep BOTH in use, Since on my setup, the header/moroso evac setup worked better under hard throttle, and the stock style setup worked better under normal driving.
Ill see if i can dig up some pics. if this is what your referring too. I used one moroso nipple for the valley and one for the valve covers. it worked really well.
since the header deal would only draw a vacuum in one direction, it would pull closed and pull from the valve covers and valley.
Ill see if i can dig up some pics. if this is what your referring too. I used one moroso nipple for the valley and one for the valve covers. it worked really well.
since the header deal would only draw a vacuum in one direction, it would pull closed and pull from the valve covers and valley.
06-11-2012, 08:35 PM
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Man I been all through this on lt1 turbo setup, I used the moroso exhaust evac and didn't have very good luck. So I just capped the egr and put a filter with baffles in each valve cover. Nice and simple and worked great at low boost (14psi 670 rwhp thru a th400), bout to push it hard so we will c how it does!
06-12-2012, 12:15 AM
#4
Man I been all through this on lt1 turbo setup, I used the moroso exhaust evac and didn't have very good luck. So I just capped the egr and put a filter with baffles in each valve cover. Nice and simple and worked great at low boost (14psi 670 rwhp thru a th400), bout to push it hard so we will c how it does!
I'm tempted to see how many pounds it pulls but it did make an assload of noise and want to suck a red rag out of my hand...
06-12-2012, 08:03 AM
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Man mine didnt pull that much, and seemed like I still had pressure problems. So I decided to get rid of all that crap and run breathers. Like I said I tried a few diffrent ways to get vacuum on my crake case but didn't have any luck. IMO filters are the way to go without dropping and bunch of money on a vacuum pump setup.
06-14-2012, 08:23 PM
#6
i actually used a series of check valves to keep BOTH in use, Since on my setup, the header/moroso evac setup worked better under hard throttle, and the stock style setup worked better under normal driving.
Ill see if i can dig up some pics. if this is what your referring too. I used one moroso nipple for the valley and one for the valve covers. it worked really well.
since the header deal would only draw a vacuum in one direction, it would pull closed and pull from the valve covers and valley.
Ill see if i can dig up some pics. if this is what your referring too. I used one moroso nipple for the valley and one for the valve covers. it worked really well.
since the header deal would only draw a vacuum in one direction, it would pull closed and pull from the valve covers and valley.
08-30-2013, 08:59 AM
#7
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PCV for forced induction - This is an old post but I'm looking for similar answers and since no pictures were ever posted on this I'm going to post the design I'm considering, which sounds similar to what was proposed here.
Since there's so much debate on open system (breathers) vs closed system, I decided to try and fab up something that could give me the best of both worlds: crankcase ventilation so I don't blow out my seals or dipstick from blowby, without putting any unneeded oil/sludge back into the intake, and without putting un-metered air into the engine.
The basic design uses two catch cans and the check valves mentioned to allow pressure out but no unmetered air in. The fitting on the passengers valve cover allows fresh post-maf metered air into the engine under vacuum. THe check valve on that side prevents pressurized air/oil vapor from going back to the intake air. The Check valve and catch can w/ breather on the other side allow pressurized blowby gases out and the check valve keeps unmetered air from flowing in. The second catch can and check valve are between the PCV and the intake, removing at least some oil vapor before it makes it to the intake. The extra catch can and hose cost a few extra bucks, but it seems worth it to me to avoid the disadvantages I've read in other posts about valve cover breathers pulling air etc.
I know there's some wicked big brains in here that can tell me if this has any glaring issues. Once I know it's solid, I'll buy and install and test it out and report back.
This is really designed for boosted motors, would probably be overkill for non F/I engines.
My car: Too many upgrades on car to list everything, relevant engine info:
94 Trans Am GT. Was making 498 rwhp before recent rebuild, I've lowered the compression slightly with new pistons/rings to 9.5:1 but fixed some plumbing issues that should raise boost pressure, so I expect to be making even a little more now.
Procharger P600b / intercooled approx. 9-10lbs boost
Since there's so much debate on open system (breathers) vs closed system, I decided to try and fab up something that could give me the best of both worlds: crankcase ventilation so I don't blow out my seals or dipstick from blowby, without putting any unneeded oil/sludge back into the intake, and without putting un-metered air into the engine.
The basic design uses two catch cans and the check valves mentioned to allow pressure out but no unmetered air in. The fitting on the passengers valve cover allows fresh post-maf metered air into the engine under vacuum. THe check valve on that side prevents pressurized air/oil vapor from going back to the intake air. The Check valve and catch can w/ breather on the other side allow pressurized blowby gases out and the check valve keeps unmetered air from flowing in. The second catch can and check valve are between the PCV and the intake, removing at least some oil vapor before it makes it to the intake. The extra catch can and hose cost a few extra bucks, but it seems worth it to me to avoid the disadvantages I've read in other posts about valve cover breathers pulling air etc.
I know there's some wicked big brains in here that can tell me if this has any glaring issues. Once I know it's solid, I'll buy and install and test it out and report back.
This is really designed for boosted motors, would probably be overkill for non F/I engines.
My car: Too many upgrades on car to list everything, relevant engine info:
94 Trans Am GT. Was making 498 rwhp before recent rebuild, I've lowered the compression slightly with new pistons/rings to 9.5:1 but fixed some plumbing issues that should raise boost pressure, so I expect to be making even a little more now.
Procharger P600b / intercooled approx. 9-10lbs boost
