0Jeff @ TPE

Here is a layout of the PCV system I designed..

It is set up so that I am able to run and maintain a PCV system, but in the event of excess CC pressure, it blows it off. When the system comes back to a vacuum situation, that BOV closes and stabalizes the CC pressure. (Its actually just a one way zero cracking pressure valve)

The vacuum regultaor is in place so that under extreme vacuum conditions (HEAVY deceleration) the regulator would open and reduce CC vacuum. In turn, this will stop the intake from ingesting oil..

This is on a positive displacement blower that has a MAFLESS SD tune..

Suggestions??

Warp Factor

Where does fresh air enter the crankcase, or is the object to maintain a vacuum?

IM QUIKR

I'd reverse it so that the krank vent is on only the front pass. valve cover and the rears connect to the intake. This would balance the vacuum better and be more efficient at clearing the crankcase. If you need two lines to the Krank vent then the motor is probably toast anyway. That's a whole lot of blow-by.

If you don't need actual vacuum in the crankcase then you could eliminate the Krank Vent altogether and use it as a fresh air port.

0Jeff @ TPE

The motors brand new, so its defiantely not toast.
I didnt really think of swapping it around. I guess thats a option. This isnt difinative. We will be testing it out before its 100% final. If we find that it needs to be tweaked, then we will do so..

So what do you think of the overall design??

I mean, hell, normally boosted guys dont run PCV's all together. So ANYTHING is better than nothing right??

IM QUIKR

Jeff,

The design is sound. Just to be clear though, the PCV is actually a check valve and not the stock PCV valve. correct? If not you need a real check valve like the McMaster Carr unit. It costs about $10 but it has the Viton seal and low crack pressure of 0.3#s. The stock unit can't hold back boost and you'd be well advised to disconnect it until you have something as strong as the Krank Vent but no need to dump that much cash for a simple check valve unless you need BLING.


IQ

NemesisC5

Tony @ MPH

After much thinking and deliberating on the advantages of crankcase vacuum vs. the disadvantage of swallowing crankcase gasses/oil, I came to the conclusion that for any high power car, elimination of the PCV is the best overall solution, with a remote mount breather to prevent the engine bay from getting oily.

Not trying to poo-poo your design or plans, but no matter what, if you have a PCV -- you're going to suck oil into that intake, and it will degrade your octane.

NICK YOSKIN

yeah tony??? what'cha think i did with ya buddie...

see them hiding behind the fog lights?[IMG][/IMG]

RED99

Nick, do you think you can get a bigger picture?

Has anyone tried running just a pair of Krank Vents (One on each side), with no breather, and no PCV, with a sealed motor? The Kank Vent would blow out positive pressure, and keep any negative pressure.

Hool97

My system is identical to yours But i use see through fuel filters(cheap autoparts store stuff) in the two lines. I have vaccum in the crank when I shut down( you can hear a hissing sound from the dipstick). When pressure builds a use the McMaster check valves to make sure pressure is released. My intake is dry after 1000s miles. My catch cans have a little watery/oil in them at times and I can monitor the amount of oil through the system with the filters.

I don't know how it works with >14lbs of boost though.

0Jeff @ TPE

I would normally agree with you Tony.

But in my situation, since I am running a KB blower, my intake track isnt pressurized. So my PCV system will ALWAYS be under vacuum. Although I know thats kinda what your talking about, but it will only be a very low vacuum. Not enough to create a problem wil oil contamination.

The port that is running to the intake tube is routed through a catch can. If for some reason I sense that there is vapor passing through the AMW catch can, then I will run a vapor seperator in line.

The main functioning part of the system is off the back of the motor. In the event of excess pressure, the valve will open and blow off to the atmosphere.

IM QUIKR, Your right..After I made this picture, I found a 3/8's barbed check valve that would work perfectly. Again, being that this valve will see less than 1-2psi of pressure, all it really needs to do is seal when the PCV is pulling vacuum. Even then, it will be less than 15".

In a nutshell, this setup will allow me to have a functioning PCV system during normal driving conditions, yet allow me to boost as high as I need without pressurizing my crankcase..

Tony @ MPH

I'll admit I don't know anything about the ins and outs of the KB, but it's not crankcase pressure created by a pressurized intake tract that creates the situation I am talking about.

Every motor will always have oily gas in the crankcase and any crankcase ventilation system that creates vacuum on the crankcase through the intake will always suck oil vapor into the intake. That's all I'm saying. Even completely stock C5s end up with oily intakes because of this reason. On stock cars it doesn't necessarily present an issue but on a heavily modified one that will be running a lot of boost and timing, oil in your intake could be meaningful.

JMHO.

0Jeff @ TPE

I completely understand what your saying.
From my understanding, (and I could be wrong) one of the main reasons most guys who have F/I, eliminate their PCV system due to the fact that the boost creates considerably more blow by. Add the fact that the intake is pressurized, and you get a situation where you need to either risk blowing the dipstick through the hood, OR vent it to atmosphere..

With my car, since my intake isnt pressurized, I can still have some of the benifits of the PCV. I PERSONALLY feel that the benifits of a sealed PCV system outweigh the possible problems. As long as you take the necessary precautions to eliminate the oil in the intake (ie..catch can, vapor filter) you shouldnt have a problem.

Hopefully, being that I will not only be blowing excess boost to atmosphere (just like everyone else) but will also be PULLING the gasses out of the crankcase under vacuum, it will have the best of both worlds.

Because frankly, I am sick of how dirty the engine bay gets by venting to atmosphere.

In a perfect world, I would prefer to run a vacuum pump. But unfortunatly, I havent found a setup that works with an 8 rib pulley system.

RJW

It's simple...piggyback onto an idler and run a different belt for the vac pump...if you still had the oem wpump, it makes a nice easy install from either side of the engine bay.

You'll end up with a vac pump sooner or later, so why fight it???

Or go electric and have it come on under boost???

I may get a chance on the dyno to do a with/without comp..unless things get too sticky

NemesisC5

c5mtl

bullitt4110

Why are you bringing back mulitple treads from 2007 on pcv set-ups?

1%r

Tis a little older than 45 days.