Deleting the Crankcase vent?
 

Just looking for your thoughts on this, maybe someone who had the valve covers off can chime in. If you look there is a PCV system as illustrated by hose 1 and hose 13. These take the crankcase gasses and route them into the intake via the PCV Valve (item 3).

But now if you look at lines 6 and 14 they appear to also run from the crankcase to each of the intake tubes, this time with no valving at all.

http://img.photobucket.com/albums/v2...ps56d1b153.jpg

With Boosted Performance's kit small filters are placed where the hose would connect to the stock intake letting it vent to atmosphere.

http://img.photobucket.com/albums/v2...psd751c726.jpg

But why is this even needed if you have the PCV system as shown by lines 1 and 13? Could one just not block these lines and let the PCV valve take care of the crankcase gasses?

I am curious if maybe there is another reason for these valves and a picture of the underside of the valve covers would provide the answer. Or maybe someone has done this already?

Good question Mitch.

Found what I was looking for, another reason to use the search :cool:



This was from
http://www.the370z.com/forced-induct...tch-can-2.html


Id delete my post but I figured it might help someone out down the road. :icon17::tup: It also makes me wonder about TT kits that keep this crankcase vent hose in their intakes, when you do this your essentially loading your crankcase up with the same amount of boost that your intake tubes are seeing, and this cannot be good for the seals. Not to mention your not working the piston both ways as they try and move the air about the crankcase.

So if you wanted to do the Catch can setup and vent the outlet to ATM then there is no reason you would need to run this second breather.

The only reason I haven't is why buy two filters and plugs for the intake for no purpose. But it looks cool though.

Its more for the Forced Induction guys who dont have the inlets on the boost tubes :)

I deleted hose 6 & 14. Who wants blow-by gasses to b dumped back in your Ntake @ near/@ WOT runs? Not me....

What about the coolant running through the throttle bodies? Is this to keep it cooled or heat it up?

Its to keep them from freezing up in colder climates. You dont want to have one of those valves stick open, it would make for a baaaad day. haha

Ok, sounds about right. Any advantages in removing this in hotter climates?

It would probably help a tad bit with IAT's but I am not sure how much or if it is even noticeable.

I would leave the crankcase breather's there, especially in a boosted car. Recirculating them reduces stress in the block and helps the piston rings seat.

deleting 6 and 14 is a bad idea for NA as you'll get idling issues.
look here: http://www.the370z.com/engine-drivet...e-problem.html

even if you disconnected them from your intake and whacked a small filter on the ends, you'd be creating another problem - unmetered (hotter) air entering the engine.

it's all part of a circuit where 1 and 13 are under vacuum and suck the ccv gases in to be burnt up. 6 and 14 are the fresh air supply lines, to replace the ccv gases, oil vapour etc sucked out via 1 and 13. ever wondered why you dont see oily gunk in your intake pipes?

Interesting thread Mitch! :tup:

I forgot about this thread. After thinking about it a year later and reading your post I agree. 6 and 14 with the check valves are only able to "suck" air out of the crankcase. When running boosted under load the PCV valve closes and all is well in the world. So when you are idling you are sucking air in through lines 6 and 14 and into the intake manifold.

:tiphat:

Or just block off the holes in the intake tube.

Subd

But if you do that then lines 6 and 14 (and the filters on them) are going to be exhausting much more than they already are, which could cause oil vapour to start making a mess of the engine.

Yea I just haven't seen that over a period of a year in track environment with my car. And the front two are freely open.

:iagree: yeah, why would you do that?

Same here. minus the crazy track time.

venting the PCV valve will not harm the motor, only reason why its recirc into the intake is for emissions purposes

just whatever you do dont close the PCV, either have it recirc or vta, if you close it off entirely, you will harm the motor

I always run PCV systems as they come from the factory, no harm done. When I turbo the car, I just relocate the fresh air vents to pre-turbo how they come on factory turbo cars.

The oil going through the intake is extremely minimal. It builds up a thin residue inside the piping, but its never slowed my car down or caused a failure. I never really understood all the stress over catching it in a can and all the hoses all over the place. But I wouldn't eliminate the setup either.

The way the BP turbo kit has you do it makes plenty of sense since the turbo inlet is rather far away from that point.

Sorry, you're wrong. I've had breather filters on my valve covers for over four years w/thousands of miles. No idle issues and no "oil residue" in my engine bay. I don't want oil residue in my intake pipes and oil/dirt/gunk making my throttle bodies stick.

I know I’m reviving a decade old thread, so no one may even have this info anymore. Can I check Spohn, if I run vents on the rear ports (that usually connect to the intake tubes), and leave the front PCV hoses (with the check valves, that connect to the front of the manifold) connected like OEM, will that work fine?

I’m seeing so much conflicting info on the PCV and CCV system for these motors, hard to make heads or tails of it.

Yes, running rear ports vented to atmosphere with front PCV valve is fine. The rears allow venting when the PCV valve closes.

I speak from experience, if you block the rears with the PCV valves up front, you will create a too much vacuum that it will pull oil up enough to cause the low oil light to come on.

ideally, if you want to keep the PCV valve, utilize a closed system with the rears plumbed to the intakes to assist in bring fresh air or help suck the vented pressure when the PCV valve closes.

otherwise, vent everything to atmosphere, front and rear.

I am speaking with regards to a NA setup.

I know for the SR20 engines, its seen to be most benefited to run it how Phunk mentioned so it seems it applies to boosted VQ also.

I ran the EPS PVC delete kit which blocks the rears and puts breather filters on the front for over 5 years and didn't run into any issues with oil consumption; I can't say for the opposite (fronts open, rear blocked) as I don't have any experience doing so.

I'm currently installing my turbo kit (BP) and my tuner recommended venting both front and rear ports.

I removed my PCV valves, and I run both ports (PCV and Valve cover vent) with 10an lines to a catch can. I have two catch cans. One for each bank. Mine vent to atmosphere.

https://www.realstreetperformance.co...er-filter.html

Spooler, where do you have your cans mounted? I'm trying to find a good location to mount some catch cans but space is limited, as I'm sure you know.

I have two. You can see them in this video. I have extra room because my intake pipe comes over the radiator support.

...don't think the video posted :icon17: