Are there any disadvantages to running an open loop pcv system other than legality issues. I'm debating on how to set up my catch cans. If I run with the catch can in between the oil seperator on the back of my block and the intake manifold (ala TOO's catch can set up for operational pcv), I get good crankcase evacuation off-boost, but during boost only the valve cover breather will be open for ventilation. If I run open pcv (valve cover and oil seperator to a catch can w/ filter to atmosphere) I'll get better evacuation while in boost, but off-boost may suffer. Any drawbacks on a street driven vehicle?


[Modified by DSF, 12:04 PM 3/18/2002]

 

Your oil gets dirtier faster, so you should change it more often.

 

Thanks, but I was looking for an answer that was a little more technical in nature. Anyone else?

 

Disadvantages - none. PCV system was created for emmisions. If you think about it, eliminating the routing of these gases back into the manifold would help horsepower....hell, these gases AREN'T combustible, right.

Yeah, probably not what you were looking for...but I'm not sure what kind of answer is going to satisfy your Q. Are you wanting to stay legal or just looking for the best setup, legality aside?

 

Best set-up really. Legality isn't too much of a concern. I can always hook up the PCV system for emmisions testing when needed. My main concern with open loop was crankcase evacuation during vacuum/off-boost. Meaning would there be enough without manifold vacuum helping things out.

 

There is no disadvantage to running an open system, as long as its working. Remember that for the system to be working right the crankcase vapors need to be cleared out and fresh air needs to replace it.

If you run an open system its going to be hard to get this right.

I've done a lot of research with this....from what I've seen you can only have your system working in boost or in vacuum. Since most of us have daily drivers we choose to have our set up for vacuum, which is a valve cover breather and a catch can between the engine and the intake manifold.

 

main disadvatage...noise...decible level is a cop magnet...sorry not technical but factual!

 

Miraz, open loop PCV......not open loop wastegate

 

That's what I was kind of thinking/afraid of. Hmm, I guess I'll compramise. Run the catch can between the engine and intake manifold to keep vacuum PCV operation. Then see if there is any more places I can open up (besides the valve cover beather) to get more fresh air in/out. Maybe I could use Moroso's "crankcase evacuation system" in addition to an operational PCV system to get evacuation in vacuum and boost. You know, the system that comes with weld-in nipples for your exhaust along with check valves to prevent reverse pressure. I think that's how it works...

 

The concept of using the exhaust to pull a vacuum on the crankcase has been around for awhile.

My old man uses it on his 454'd S10.

I'm interested in what this type of system could do for a Honda. If you decide to go this route, do us a favor and keep this thread updated.

 

Daayymmmnnn!!! Hehe.

I don't really see why it would be any different. I mean an engine is an engine... Guess there's only one way to find out

 

See this link:

http://www.theoldone.com/components/breather/

Tom

 

When I said I did a lot of thinking about this...I did a lot . I almost made an exhaust system...but theres a problem. In any exhaust with a muffler there is going to be pressure in the exhaust. Therefore exhaust run crank case clearing wont work.

You could always run a pump...but thats $$$.



[Modified by 00SilverLS, 2:45 PM 3/19/2002]

 

Hmm, I didn't think about that. Do you think the velocity of the exhaust gas at WOT is enough to create vacuum on a tube whose opening is towards the exhaust exit? (Make sense?)

 

I honostly dont know...you could always try it...but I think the pressure is up there....like 10 psi.. just a estimated guess, but i dont think that on a muffled car it will work.

 

You are correct - On a short open exhaust system it will work. But as soon as you put in mufflers, resonators and more piping you create backpressure........

 

...woops...my bad

 

ahh just remove the muffler and run striaght pipe. Might be a little loud but you said lagality aside.


[Modified by Fooser, 8:25 PM 3/21/2002]