Fuel filter catch can mod is no good

[Automobile Maniac]

I was going to do this mod today. So I am looking around and see this statement from dejontool.com--

http://www.dejontool.com/dsm-cip-faq.htm
Do I need the Valve Cover Vent tube on my new intake pipe?
What does the small hose from the valve cover do?
As pressure in the valve cover builds from boost pressure leaking into the engine, this tube vents it into the intake for a "closed system". Unfortunately oil from inside the valve cover comes with the air and lines the whole intake system. It collects in the Intercooler and degrades cooling, fouls the throttle body and collects in the intake manifold also. If your engine is in good shape you can remove the hose and put a small air filter on the intake tube (like our K&N VCV filter ($17.95) which can be cleaned and reused) or order an intake pipe without this tube. If your engine puts out alot of oil, you'll need a catch can. Drivability and performance will not be effected However you will be defeating emissions (which is illegal except for offroad). Do not plug the hose or install a fuel filter as the backpressure will impair venting.

So, if thats true, then what would basically "impaired venting" do?
Now I am thinking about not even doing it.

[97_3clipse]

you need to double read that FAQ....
"Do not plug the hose or install a fuel filter as the backpressure will impair venting. "

thoes two things will make it harder for the VC to breathe

[Automobile Maniac]

I see what your saying. Guess I read it wrong. Sounded like they were saying--do not plug the hose or do not install a fuel filter. In other words I thought it meant a fuel filter would cause backpressure.

[kjewer1]

It will Venting the crankcase is very important, especially at high HP (cylinder pressure). In my case I have both the side port vented and the rear port (used to be the PCV) with 3/8th rubber fuel line. It still isnt enough to completely vent the crankcase. Ideally, you would actually have a vacuum in the crankcase. It does two things. One, it gets a better seal from the rings. Two, there is less air (or less dense) in the crackcase, so you get lower pumping losses (don't forget the bottoms of the pistons pump air too ). So its not a cut and dried type situation, there are vary grades of how well that is vented. From full boost pressure, to an artificial vacuum applied with a mechanical or electric pump, and everything in between. The less pressure the better is the moral of the story.

[whitetiger777]

If this is the mod I think it sounds like, then I originaly put a fuel filter in the line that goes from the valve cover to the intake and had no problems. I just recintly replace the whole line with a small airfilter nad pluged the hole on the intake and am still having no problems. There are two other DSM guys that I know who have done the same thing with no problem also. One of there is even running a 20G, the other, along with my self are running Evo III Big 16Gs.

[Automobile Maniac]

Thanks for your reply, that really helps and gives me the confidence to do it. I'm gonna go for it.

[kjewer1]

Another thing worth noting, is that if crankcase pressure gets too high it will blow out the dipstick. Even with both ports vented my dipstick can pop up when I run high boost. I use a spring or safety wire to hold it down, might be visible on some of the pics on my site. At any rate, if you dont pop the dipstick CC pressure should be fine.