How Do You Boosted Guys Run Your PCV System?????
#12
LS6 valley cover, breathers on valve covers, catch can between valley cover and intake before blower to evacuate fumes from LS6 valley cover with built in PCV.
Last edited by MFIC; 04-22-2008 at 01:28 PM.
#14
Yes it is. The pcm is under the filter laying flat. You have to move the brake distro block down and back just a bit to clear the 90 out the back of the head unit. I used a poly 90 and a 4" exhaust u bend cutting it down to th size i needed.
#17
Not sure that the breathers alone is enough. With the cost of my engine antother 150.00 in a proper pcv system is well worth it. My engine builder TSP also insists on evacuation of the crankcase on there motors and not to run just breathers.
Thought this was a good write up from TLewis4095 on LStech:
How will you evac the water vapor, unburnt fuel, combustion gasses, & other contaminates when they flash off? Breathers alone won't do it....and if you do not have a good vacum pulled system they just re-condense after your motor cools down contaminating the oil causing corrosion & premature wear issues. The breathers just allow the pressure to not build up but do nothing to remove & ventelate the crankcase.
On a gas powered race application evac tubes run from the breathers to 1 way valves in the collecters that pull the vapors out at high speed/RPM. For Alky race motors we use a belt driven pump to pull vaccum as there is a tremendous amount of unburnt fuel getting in the crankcase & moisture as the alky acts like a sponge. We use a vacum relief valve in 1 valve cover so we don't pull over 14-15" vaccum..(more pulls the oil off the wrist pins) and it is plumbed into a breathered catch can that we have to empty after every 3-4 runs.
On a street car like your you must have a good functioning PCV system or you will have issues. The key is the system MUST pull the vapors out, and the vaccum must be metered by a PCV valve or as in the LS6/LS2 vally cover a fixed orfice to control it. You must also have a filtered fresh air source (stock this comes from the front of the TB filtered by your primary air filter).
The most effective system will pull filtered air through the entire crankcase & into the intake manifold where it is burnt in the combustion process. The problem is the oil vapors condensing in the intake & contributing to detonation. A properly installed good functioning catch can (the bigger the better for surface area for the vapors to contact & condense back into liquid so it does not pull into the intake) solves most issues.
In a big cube or a FI application you need the extra breathing of a filtered breather.
Hope this helps, there are hundreds of wrong mods out there either causing seal failures or unfiltered allowing dirt/water/gravel/etc. to be sucked directly into the crankcase slowly wearing the motor out.
Thought this was a good write up from TLewis4095 on LStech:
How will you evac the water vapor, unburnt fuel, combustion gasses, & other contaminates when they flash off? Breathers alone won't do it....and if you do not have a good vacum pulled system they just re-condense after your motor cools down contaminating the oil causing corrosion & premature wear issues. The breathers just allow the pressure to not build up but do nothing to remove & ventelate the crankcase.
On a gas powered race application evac tubes run from the breathers to 1 way valves in the collecters that pull the vapors out at high speed/RPM. For Alky race motors we use a belt driven pump to pull vaccum as there is a tremendous amount of unburnt fuel getting in the crankcase & moisture as the alky acts like a sponge. We use a vacum relief valve in 1 valve cover so we don't pull over 14-15" vaccum..(more pulls the oil off the wrist pins) and it is plumbed into a breathered catch can that we have to empty after every 3-4 runs.
On a street car like your you must have a good functioning PCV system or you will have issues. The key is the system MUST pull the vapors out, and the vaccum must be metered by a PCV valve or as in the LS6/LS2 vally cover a fixed orfice to control it. You must also have a filtered fresh air source (stock this comes from the front of the TB filtered by your primary air filter).
The most effective system will pull filtered air through the entire crankcase & into the intake manifold where it is burnt in the combustion process. The problem is the oil vapors condensing in the intake & contributing to detonation. A properly installed good functioning catch can (the bigger the better for surface area for the vapors to contact & condense back into liquid so it does not pull into the intake) solves most issues.
In a big cube or a FI application you need the extra breathing of a filtered breather.
Hope this helps, there are hundreds of wrong mods out there either causing seal failures or unfiltered allowing dirt/water/gravel/etc. to be sucked directly into the crankcase slowly wearing the motor out.
#18
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I'm running an LS6 valley cover, PCV valve feeding to the intake side of the blower so that it never sees boost, only vacuum. I have something like a catch can inline, it stays dry, the LS6 valley cover is very effective at removing the oil. The other hose from the other valve cover goes to the stock fittiing upstream of the throttle. It is the place that the air goes into the crankcase, filtered by the engine air filter.The LS6 valley cover does not have a PCV valve built into it, only an oil separator. You need to add an inline PCV valve.
#19
Yes I have a PCV between the catch can and valley cover. I incorrectly spoke saying the LS6 valley cover had a PCV. For some reason I had it in my head that it had a PCV thank you for the correction. I did use a PCV or what I would call a oneway ball check valve. I found it at the auto parts store. I just asked to look at the 20 or so PCV,s they had behind the counter and found one that was a inline type that fit the -6 line I used.
Last edited by MFIC; 04-22-2008 at 07:09 PM.
#20
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Me too. knock on wood. I was having alot of spew out of the breather, and then i disconnected and plugged the line that flows air into the valve cover and that solved my problem.