PCV set-up

Post by **kouki_hmongster** » Sun Sep 14, 2008 10:31 pm

here's my set-up, tell me what you guys.

air/oil separator to catch blow-by gas, it is actually for an air compressor.

check valve is to prevent boost from getting through to my pcv valve since the stock pcv valve wasnt made to handle boost. for my valvecover breather it is hooked up direct to turbo inlet pipe.

got this idea of check valve(one way valve) from:http://www.stealth316.com/2-krankvents.htm

Modified by kouki_hmongster at 2:22 PM 8/26/2009

Post by **WDRacing** » Mon Sep 15, 2008 4:09 am

The only thing you could do to improve this is to add another oil/air separator to the VC-turbo inlet-line. That way if any blow-by does make it that far you're not coating the inside of the compressor, piping and intercooler with it. Certainly not a must...

Doing this is definitely an improvement over the stock system.

Take some pics once it's installed.

WD

Post by **kouki_hmongster** » Mon Sep 15, 2008 6:00 am

i have a catchcan laying around , should i use that or actually get an air/oil separator for the vc to turbo inlet pipe?

Post by **WDRacing** » Mon Sep 15, 2008 7:52 am

The catch can will work

Post by **neverlift** » Mon Sep 15, 2008 7:55 am

I'd use it on my vc. I dont get any blowby out the pcv however I gets me plenty into my turbo starting to piss me off time to do a catch can...

awesome diy setup btw, is the brass straight like a ball spring boost controller type deal? curious cause thats an extremely cheap alternative to the link

Post by **WDRacing** » Mon Sep 15, 2008 8:06 am

The reason you have blow-by from your VC is because you already have PCV issues. The standard PCV doesn't do well with boost, so not only is it not removing blow-by when on boost, but it's actually leaking air into the crankcase. Which is why you have crap leaking out of the VC. The VC is supposed to be for the intake of fresh air...nothing should be exiting it. When gas leaves the VC it's because you have blow-by problems.

WD

Post by **neverlift** » Mon Sep 15, 2008 8:18 am

the only part of my pcv system left is the box on the motor, its hose is dumped, like many run with success

I get my vc is tied to turbo inlet... should I let the vc VTA and run my pcv to the turbo inlet? confusing me now, please clear it up

Post by **WDRacing** » Mon Sep 15, 2008 9:09 am

Ok...

Here's how the crankcase ventilation system works. The blow-by is caused by compression leaking past the piston rings, even with gap-less rings there will always be blow-by. The blow-by causes your oil to become gunk ed up with fuel and soot from the combustion process. This is the main reason your oil get tinted dark, not wear. The only way to remove those vapors and crap from your crankcase is through the stock crankcase evacuation system that includes the PCV valve. The box attached to the motor is just an air/oil separator. The only thing that pulls the fumes out through the PCV valve is vacuum from the intake manifold. Which you have now completely taken out of the system. So at the moment, you have ZERO crankcase evacuation.

Having it dumped to the ground or a catch can does absolutely nothing. These abstract catch can's that everyone has fabbed up are useless without the PCV hooked to the intake.

The reason you have vapor escaping through the VC is because that's route of least restriction. Since it can just go up the oil galleys into the head and isn't being sucked out via PCV-intake vacuum.

Does that make sense?

Post by **eazye2000** » Mon Sep 15, 2008 10:57 am

PCV, and Valve Cover ports/holes/gimmicks both go to the inlet of my catch can. The catch can is then pulled from by a port/hole on my turbo suction/inlet pipe after my MAF.

That's how I do it, and it works great. Another thing I have seen is instead of going to your intake somehow, you weld a small pipe to your exhaust at an angle, and use your exhaust flow to pull out your crankcase. Not sure about that, but I have seen pictures of it and the guy says it works great.

Post by **WDRacing** » Mon Sep 15, 2008 11:27 am

Exhaust type crankcase vents work ok, not as good as a external pump, but decent.

The setup you have Eric is meh at best. There is no vacuum pre turbo so during idle or unspooled driving you have zero crankcase evacuation. You may THINK it works good, but what does that mean? How do you know it's working?

The key is to have SOME type of vacuum pulling fumes OUT of the crankcase. When the line from the pcv is hooked pre turbo you have some suction force being applied to that line, but that's also when the cylinder pressures are the highest and you have the most blow-by.

The stock system was designed to pull crankcase vapors in NA form. Right now you have NO vacuum pulling the vapors when driving off boost.

The OP is the only method that is an actual working system so far in this thread.

Post by **kouki_hmongster** » Mon Sep 15, 2008 2:38 pm

neverlift wrote: awesome diy setup btw, is the brass straight like a ball spring boost controller type deal? curious cause thats an extremely cheap alternative to the link

this is a Brass Medium-Pressure Spring-Loaded Piston Check Valve. here's the spec on it:

Maximum Pressure: Viton: 1000 psi @ 400° FCracking Pressure: 0.3 psiTemperature Range: Viton: -20° to +400° F

Engineered for an extra-low cracking pressure of just 0.3 psi. Valves have a brass piston, 300 series stainless steel spring, and your choice of Buna-N or Viton seats.

got this off http://www.mcmaster.com part #7775k53 $22.33

female x female hose size: 3/8" length: 2 5/16" bought the barb x mip(3/8"x3/8") fitting from homedepot for around $1.60 each.

saved me a lot of $$ compared to krankvent....hope this help out others too.

Post by **480sx** » Mon Sep 15, 2008 4:20 pm

McMaster once again FTW.

I gotta throw in my 2 cents here.. Your basically doing a lot of work to rig up a PCV system nearly identical to stock. Stock pcv system sucks for boost. When you need PCV the most, you have none because your check valves are closed. Also im not sure how well that separator is going to work with oil. They are designed to keep water out of your compressed air in your shop..

I would rig up one like Eric or I have that uses the turbo intake to create a vacuum on the crank case. This way it works all the time, in boost and out of it. I have my valve cover vent and my stock breather seperator hooked up to a catch can, then to my pre-maf. Or use the exhaust venturi effect vacuum, that works great in boost.

A electric vacuum pump might be the holy grail of PCV systems, however theres not many people who have done this so its mostly just theory. Also, unless you have a Quest alternator upgrade, your putting a lot of stress on an already overtaxed electrical system. The Ka's charging system is a joke.

Post by **WDRacing** » Tue Sep 16, 2008 4:23 am

480sx wrote:McMaster once again FTW.

I gotta throw in my 2 cents here.. Your basically doing a lot of work to rig up a PCV system nearly identical to stock. Stock pcv system sucks for boost. When you need PCV the most, you have none because your check valves are closed. Also im not sure how well that separator is going to work with oil. They are designed to keep water out of your compressed air in your shop..

I would rig up one like Eric or I have that uses the turbo intake to create a vacuum on the crank case. This way it works all the time, in boost and out of it. I have my valve cover vent and my stock breather separator hooked up to a catch can, then to my pre-maf. Or use the exhaust venturi effect vacuum, that works great in boost.

A electric vacuum pump might be the holy grail of PCV systems, however theres not many people who have done this so its mostly just theory. Also, unless you have a Quest alternator upgrade, your putting a lot of stress on an already overtaxed electrical system. The Ka's charging system is a joke.

The air/oil separator is used on compressor for oil as well. Just depends on the compressor and whether you lube the guns or the have an oiling system. Then again, that particular unit looks like a moisture separator. Which fortunately for us has already been tested for us by other pioneering enthusiasts from GN's to Fox Mustangs.

Eric's and your setup has ZERO vacuum off boost. So you're mistaken when you say it works all the time. Put a vac gauge on the intake pre turbo and start the car. Tell me if you are pulling vacuum. If you are pulling vacuum it's because your air filter is restricted BADLY. So you aren't pulling crankcase fumes off boost.

Yes, you need crankcase ventilation more when you're on boost because of the cylinder pressures being that much higher...BUT...as soon as your off boost those fumes are sucked out via intake vacuum. Just like they are on the SR/RB/VG etc.

The advantages that the OP has created are simply eliminating the PCV leak and adding a filter to the system to keep oil out of the intake manifold. Also, it's a filter that can be changed. Anyone ever change the air/oil separator on the stock unit?

The most ideal setup other then a vacuum pump would be the OP's setup combined with the pre-turbo hose hooked to the VC, or the exhaust scavenge system. Obviously the pre-turbo/VC option is the easiest. That way you're pulling fumes ALL the time. I would also add a catch can or air/oil separator to the pre-turbo line though...unless you like the compressor and fmic piping covered in oil.

WD

Post by **480sx** » Tue Sep 16, 2008 8:47 am

Good stuff. So really a good setup without a vac pump would be a mix of the stock setup and the pre turbo vac source setup. Gona get that going for this next build, ill do a writeup while im at it.

Post by **WDRacing** » Tue Sep 16, 2008 9:04 am

Awsome

I'm going to do the stock setup like the OP and have a boost referenced vacuum pump for on boost evac.

Post by **JaeTea** » Tue Sep 30, 2008 1:02 am

How would this work with a SOHC.

The PCV is already located on the manifold?

Post by **2FourTee** » Tue Sep 30, 2008 7:48 am

WDRacing wrote:
The air/oil separator is used on compressor for oil as well. Just depends on the compressor and whether you lube the guns or the have an oiling system. Then again, that particular unit looks like a moisture separator. Which fortunately for us has already been tested for us by other pioneering enthusiasts from GN's to Fox Mustangs.

Eric's and your setup has ZERO vacuum off boost. So you're mistaken when you say it works all the time. Put a vac gauge on the intake pre turbo and start the car. Tell me if you are pulling vacuum. If you are pulling vacuum it's because your air filter is restricted BADLY. So you aren't pulling crankcase fumes off boost.

Yes, you need crankcase ventilation more when you're on boost because of the cylinder pressures being that much higher...BUT...as soon as your off boost those fumes are sucked out via intake vacuum. Just like they are on the SR/RB/VG etc.

The advantages that the OP has created are simply eliminating the PCV leak and adding a filter to the system to keep oil out of the intake manifold. Also, it's a filter that can be changed. Anyone ever change the air/oil separator on the stock unit?

The most ideal setup other then a vacuum pump would be the OP's setup combined with the pre-turbo hose hooked to the VC, or the exhaust scavenge system. Obviously the pre-turbo/VC option is the easiest. That way you're pulling fumes ALL the time. I would also add a catch can or air/oil separator to the pre-turbo line though...unless you like the compressor and fmic piping covered in oil.

WD

Good info.

Post by **supra33202** » Wed Dec 30, 2009 1:38 pm

kouki_hmongster,

Could you list the parts (links?) you used for your PCV system?

Thanks!

Post by **martins_240sx** » Sun Jan 03, 2010 11:59 am

Can you give me your opinions on wether this will work.I think that my drawing will setup my pcv so that i get evacuation in boost and out of it. being at idle it will recieve vacuum from the manifold and when boost pressure increases the one way check valve will stop boost from entering the crankcase and at the same time through a venturri effect be pulling vacuum from the intake pipe preturbo. I also forgot to ad another check valve on the line between the intak pipe and the t-fitting. the t-fittings will shut depending on which vacuum source is being used....Valve cover will be vented to atmosphere with filter

PCV set-up

PCV set-up

Re: PCV set-up (kouki_hmongster)

Re: PCV set-up (WDRacing)

Re: PCV set-up (kouki_hmongster)

Re: PCV set-up (kouki_hmongster)

Re: PCV set-up (neverlift)

Re: PCV set-up (WDRacing)

Re: PCV set-up (neverlift)

Re: PCV set-up (WDRacing)

Re: PCV set-up (eazye2000)

Re: PCV set-up (neverlift)

Re: PCV set-up (kouki_hmongster)

Re: PCV set-up (480sx)

Re: PCV set-up (WDRacing)

Re: PCV set-up (480sx)

Re: PCV set-up (WDRacing)

Re: PCV set-up (WDRacing)

Re: PCV set-up (kouki_hmongster)

Re: PCV set-up (supra33202)

Nissan Forums

Infiniti Forums

Datsun Forums

Technical Forums

Classifieds / Marketplace

Nissan Motorsports

General Forums