Positive Crankcase Evacuation Explained: KA24ET / KA24DET Forum: Nissan Forums / Infiniti Forums - NICOclub

 

If you think that link is correct think again

Valve Cover Breather Debate - Team Integra

You can clearly see in any diagram from honda or any other reputable engine builder, the pcv system is supposed to be "sucking in fresh air" which it does not do AT ALL. I do not know where they got this idea from. I challenge you to run outside and put your hand in front of where the nipple is on the valve cover...now have someone rev the motor and you will feel air being PUSHED out of the valve cover not sucked in.

I believe it is a greater benefit to the motor to have it vent elsewhere and not suck fumes/oil back in through the intake manifold.

 

And to totally contradict what I just said lol...yet another link

Tests on the PCV system - How Honda intended it - - Honda-Tech

 

It is very simple...

The stock system is there for emissions. For performance, open breathers work better. If you want as much relief as possible you need to run as many exits for the air as possible hence the 4 ports being used on a valve cover.

I am just still up in the air in regards to the back of the block deal...is it really beneficial at all.

 

if you don't want to use the back of the block, its not a a big deal... but you will need to check the catch can on a regular basis so you can empty it so it does not overflow...

 

here's one of the original kits produced... talks about the drain back idea a little

The Old One - Energy Dynamics : Recommended Components

 

Also, we installed a catch can system on a 245whp b-series (turbo) and to this day (a good 6 months boosted) we have yet to find more than a drop of oil in the can. This is a valve cover only setup.

 

I always just ran the shortest line possible, rubber hose from valve cover to intake tube. I have seen many with the breather filters right on the valve cover vacuum port. Thought about it and say nah I'll hook it up to my intake tube like it was before. What else would Comptech put a thing on their intake for? Reading up Honda uses possitive pressure through the valve cover meaning air is pushed into the valve cover from the intake. The point is to get fresh air into the crankcase. Then I read an article on Honda tech that confused the shit out of me because nobody could give a simple answer. What is the best for a NA motor? Nobody could come up with a simple answer to is afilter used as the breather on the valve cover good or bad? WTF.

 

My personal belief with all the reading I have done and the first hand experience with this is that honda put it there for emissions...to help burn left over fumes/gas/oil vapors. I believe the best bet for PERFORMANCE is to allow the crankcase and valve cover to breathe as easily as possible.

Honda show's that there if vacuum at the port...but there isn't. Start your car and put your hand in front of the port...air is coming out of it not going in. Rev the motor, air still is coming out not going in.

 

on my sohc turbo (maybe 200hp or so) im running a back of the block and valve cover vented setup. running from valve cover to the intake or back of the block to the intake manifold will allow oil to get into the intake track/ engine causing lower octane and buildup. i thought about going w/ a slash cut setup to help pull a vac on the block