should I eliminate my pcv system?
02-16-2008, 04:40 PM
#1
should I eliminate my pcv system? Ive done the search on here and read countless posts on different setups and ideas and im starting to think I may be better off getting rid of the pcv system all together and run 2 breathers. I know this topic has been beat to death and I guess im taking the next swing but what do you all think I should do? what are the advantages/disadvantages to keeping it or getting rid of it? I will be running around 16-18psi.
02-16-2008, 09:11 PM
#2
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.
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.
02-17-2008, 10:50 PM
#3
Teching In
Join Date: Oct 2004
Location: LOUISIANA
Posts: 43
Likes: 0
Received 0 Likes
on
0 Posts
I am glad you brought this up, I was looking at the car I bought and it has a 408 with F1R Procharger setup and the PCV valve dont have a vacumm line hooked to it and the other valve cover just has a open tube. I was wondering if I needed to hook it up.
