Coolest Oil Catch Can

L33T Z34 · 09-16-2013, 03:20 PM

Quote:

Originally Posted by synolimit

And you did this how? The 370z system is hooked to the inlets. You'd have a massive vacuum leak. Also you might want to rethink that statement. Hard cornering and fast driving with dumping to the ground on other cars I've been able to dump an *** load of oil out in hard G turns. Its not good when your tires, wheels and rotors are soaked in oil.

LOL! The valve covers are baffled. IF u got this much oil puking out your valve covers, then u got bigger problems...

I plugged the holes on my accordian tubes w/pipe plugs, no vac leax there!

phunk · 09-16-2013, 03:40 PM

There are 2 parts to the PCV system. We have the check-valved vents that lead to our intake manifold, and we have the open vents that lead into our intake tubes.

I am not entirely sure why the intake manifold fed PCV vents have a check valve since the car is non-boosted from the factory.

During high vacuum at idle and such, the manifold vacuum should be pulling so much through the PCV that the air filter tube side of the system is probably pulling fresh air IN.

With both my 350z and my 370z TT setup, I kept the stock PCV system. Under boost, the PCV check valve should shut, and the only ventilation for the crankcase would be the air filter tubes.

What I only just NOW considered thanks to this thread, is that running a "stock" style PCV system in my 370z TT is causing a problem that I hadnt thought of. The difference is, my 350z was a MAP (speed density) EMS system. My 370z is not. During high vacuum idle, my PCV system should be drawing fresh air through thru my air filter tubes. So I have an un-metered air source entering my engine at idle, since my MAF sensors are just before the throttle bodies.

Huh... thank god for closed loop feedback I suppose.

Chuck33079 · 09-16-2013, 03:42 PM

Quote:

Originally Posted by L33T Z34

LOL! The valve covers are baffled. IF u got this much oil puking out your valve covers, then u got bigger problems...

I plugged the holes on my accordian tubes w/pipe plugs, no vac leax there!

He was talking about a flat 4. Lots of guys have had that problem since high gs keep the oil trapped in the head, and it comes out the breather.

synolimit · 09-29-2013, 12:27 AM

Only 2k! Wow!

1slow370 · 09-29-2013, 03:17 AM

Phunk, the pcv valves on the 370z function the same way all pcv valves on all naturally aspirated emissions controlled engines function. They are flow metering check valves. the reason they rattle and the spring inside them is so weak is because they are set up to work with the amount of vacuum the engine produces, so that at idle the valve is open but only flows a little bit of air, because the high vacuum actually lifts the piston inside the valve off the seat and up to the top of the valve where it partially closes the exit orifice of the valve. This allows the system to vent but does not introduce enough air to effect the idle to great extent. when the throttle is opened pressure rises to the point where the piston falls to about the halfway point of the valve allowing much more fumes to be vented since the engine will be able to burn them effectively. when the motor back fires or boost comes on(if F.I.) the valve shut to prevent reversion of fumes into the intake. this is where the catch can does the most work because during boost the valve is shut but often leaks allowing boost to go through the valve, combine this with blow-by past the rings and your going to building a lot of crankcase pressure that can't go anywhere with the factory setup because it is trapped between the intake pipe and the manifold. this leads to popped out dipsticks and reduced power from having a boosted crankcase pressure(not much honestly though). When switching to an external pcv intake filter now the crankcase pressure under boost can escape by going backwards through the system all over your engine bay, which is where the catch can comes in. some systems i've seen have valves or solenoids that under boost will vent the catch can to atmosphere and under vacuum allow the pcv system to function normally the below method will allow you to vent crankcase pressure, without contaminating the intake, or reverting fumes all up under your hood, and for an estimated parts cost of 5-25 dollars.

And my personal favorite pcv system is the exhaust venturii, no oil stain under the hood, no reversion out the filters from blow by on a boosted car, and i can still imagine myself mystically choking up al gore's air every time i drive. Oh and it's by FAR the cheapest if you can weld or have a buddy who can because it involves two small pieces of tube cut on an angle and roughly 4 ft of hose. (also drilled out factory valves), using seperate pcv filters and plugging the intake pipes and the manifold hoses will allow you to eliminate any source of unmetered air caused by the pcv as well

1slow370 · 09-29-2013, 03:49 AM

PCV WIN TWO of these would be the swanky way to do it.

G37sHKS · 09-29-2013, 07:15 AM

Quote:

Originally Posted by 1slow370

PCV WIN TWO of these would be the swanky way to do it.

How this stuff works?

Edit: Nevermind did some google.

phunk · 09-29-2013, 08:26 AM

Quote:

Originally Posted by 1slow370

Phunk, the pcv valves on the 370z function the same way all pcv valves on all naturally aspirated emissions controlled engines function. They are flow metering check valves. the reason they rattle and the spring inside them is so weak is because they are set up to work with the amount of vacuum the engine produces, so that at idle the valve is open but only flows a little bit of air, because the high vacuum actually lifts the piston inside the valve off the seat and up to the top of the valve where it partially closes the exit orifice of the valve. This allows the system to vent but does not introduce enough air to effect the idle to great extent. when the throttle is opened pressure rises to the point where the piston falls to about the halfway point of the valve allowing much more fumes to be vented since the engine will be able to burn them effectively. when the motor back fires or boost comes on(if F.I.) the valve shut to prevent reversion of fumes into the intake. this is where the catch can does the most work because during boost the valve is shut but often leaks allowing boost to go through the valve, combine this with blow-by past the rings and your going to building a lot of crankcase pressure that can't go anywhere with the factory setup because it is trapped between the intake pipe and the manifold. this leads to popped out dipsticks and reduced power from having a boosted crankcase pressure(not much honestly though). When switching to an external pcv intake filter now the crankcase pressure under boost can escape by going backwards through the system all over your engine bay, which is where the catch can comes in. some systems i've seen have valves or solenoids that under boost will vent the catch can to atmosphere and under vacuum allow the pcv system to function normally the below method will allow you to vent crankcase pressure, without contaminating the intake, or reverting fumes all up under your hood, and for an estimated parts cost of 5-25 dollars.

And my personal favorite pcv system is the exhaust venturii, no oil stain under the hood, no reversion out the filters from blow by on a boosted car, and i can still imagine myself mystically choking up al gore's air every time i drive. Oh and it's by FAR the cheapest if you can weld or have a buddy who can because it involves two small pieces of tube cut on an angle and roughly 4 ft of hose. (also drilled out factory valves), using seperate pcv filters and plugging the intake pipes and the manifold hoses will allow you to eliminate any source of unmetered air caused by the pcv as well

I am very familiar with how the PCV system functions. I do not experience any adverse side effects of excessive crankcase pressure even with FI because of the fresh air inlets that are used as vents when under boost. The vents are 1/2" ID and able to flow outward plenty, combined with the vacuum generated in the intake tubes from my turbos.

I already played with the PCV the other day to make sure I wasn't having any problems from my fresh air inlets pulling unmetered air. By closing the inlets, it blocked enough air to drop RPM about 50rpm until the idle control compensated after a moment, and only a couple tenths at most AF points difference until closed loop feedback compensated... So my unmetered PCV fresh air inlets are negligible as far as effecting my tune.

Otherwise... Stock PCV system (aside from fresh airs bypassing MAF) and tons of power and tons of mileage and no issues at all! Works perfect, just like my 350z has for going on 10 years!

Like I was saying, I don't fault anyone for wanting a catchcan.. But it really doesn't matter. It's not going to make my car any faster or any more reliable.

wstar · 09-29-2013, 08:41 AM

They shouldn't be unmetered on the stock PCV setup, or any of the intake designs I've seen. None of the connections are in front of the MAFs. Engine vacuum draws from the crankcase, crankcase draws replacement fresh air from the intake tubes, post-MAF.

phunk · 09-29-2013, 08:53 AM

Quote:

Originally Posted by wstar

They shouldn't be unmetered on the stock PCV setup, or any of the intake designs I've seen. None of the connections are in front of the MAFs. Engine vacuum draws from the crankcase, crankcase draws replacement fresh air from the intake tubes, post-MAF.

Correct.. Which was what I was talking about a few posts up.

Turbo 370zs are not like this because all the kits are blowing through the MAF. You could not have your PCV fresh air after the MAF because the MAF is being boosted. You would just be pumping boost straight into the crankcase.

wstar · 09-29-2013, 08:54 AM

Mo' boost mo' problems

Sh0velMan · 09-29-2013, 10:13 AM

I have a conceptual design in my head for a PCV/Catch Can setup that wouldn't have the (albeit limited) drawback of drawing unmetered air etc.

(For forced induction)

I need to get the design on paper, once I do, I'll post it here.

1slow370 · 09-29-2013, 04:19 PM

a lot of my previous post wasn't about your car either more of a general discription of pcv's and F.I. and why the stock system needs to be changed for it.

So what your saying is by plugging your pcv your idle changed slightly and your letting the computer correct for the small amount of unmetered air entering the manifold, and your very familiar with how pcv works, but are unsure of why pcv valves are on the 370z since it is not factory boosted(this might be where i am misunderstanding you)?

Also your inlet hoses for the pcv are plumbed to your compressor inlet pipe instead of those little separate filters right? in that case yeah the pcv will work fine other than the negligible amount of unmetered air, and that everything is still going to get dirty(which most people don't care about. If you hooked your pcv up to the seperate little filters instead tho you would get smokey fumes coming from the filters under boost.

Edit: also as a side note i also believe not running a catch can isn't going to cause a problem, they are a waste of money unless you just want everything to stay clean.

All of these non issues and minor annoyances is why i like the exhaust pcv fittings, other than the environment there are no downsides, no dirt, doesn't effect the way the motor runs at all, its cheap (just make sure you use high temp hose)

phunk · 09-30-2013, 01:56 PM

I have seen the exhaust PCVs used in the past and I agree that they are pretty slick and probably provide superior crankcase vacuum at high engine load where there is none in the manifold.

You are correct about how my PCV is running. My VC to IM are stock, and my VC to air filter tubes are unfortunately before the MAF due to blow-through MAF setup. But ya I played with it and it doesn't seem to be flowing enough unmetered air that my feedback cycles for idle and fuel trim cant handle it.

Usually all I will do (if needed) to a PCV system for a higher power FI car is enlarge the vents if possible, or add another if needed. My only real argument about why I dont use a catch can "just because" is only about space, organization, clean engine bay, etc. I prefer to eliminate anything in the engine bay that is not needed as, especially with twin turbos, space comes at a premium.

synolimit · 09-30-2013, 03:03 PM

Quote:

Originally Posted by 1slow370

PCV WIN TWO of these would be the swanky way to do it.

Illegal for the track but to each their own.

Phunk outside the engine bay has room.

09-16-2013, 03:40 PM	#77 (permalink)
phunk A True Z Fanatic Join Date: Mar 2009 Location: Chicago Posts: 3,668 Drives: 370 Rep Power: 974723	There are 2 parts to the PCV system. We have the check-valved vents that lead to our intake manifold, and we have the open vents that lead into our intake tubes. I am not entirely sure why the intake manifold fed PCV vents have a check valve since the car is non-boosted from the factory. During high vacuum at idle and such, the manifold vacuum should be pulling so much through the PCV that the air filter tube side of the system is probably pulling fresh air IN. With both my 350z and my 370z TT setup, I kept the stock PCV system. Under boost, the PCV check valve should shut, and the only ventilation for the crankcase would be the air filter tubes. What I only just NOW considered thanks to this thread, is that running a "stock" style PCV system in my 370z TT is causing a problem that I hadnt thought of. The difference is, my 350z was a MAP (speed density) EMS system. My 370z is not. During high vacuum idle, my PCV system should be drawing fresh air through thru my air filter tubes. So I have an un-metered air source entering my engine at idle, since my MAF sensors are just before the throttle bodies. Huh... thank god for closed loop feedback I suppose. __________________ Charles @ CJ Motorsports : Website \| Facebook \| Instagram \| YouTube Home of the 9 second, stock longblock, stock drivetrain 6MT 370z. 9.91 @ 142mph

09-29-2013, 12:27 AM	#79 (permalink)
synolimit A True Z Fanatic Join Date: May 2013 Location: Columbus, OH Posts: 5,051 Drives: 2013 Silver 370z Rep Power: 3389	Only 2k! Wow! __________________ 13 370z-

09-29-2013, 03:17 AM	#80 (permalink)
1slow370 A True Z Fanatic Join Date: Aug 2009 Location: In the D Posts: 3,732 Drives: v8 74 260z ;) Rep Power: 7251	Phunk, the pcv valves on the 370z function the same way all pcv valves on all naturally aspirated emissions controlled engines function. They are flow metering check valves. the reason they rattle and the spring inside them is so weak is because they are set up to work with the amount of vacuum the engine produces, so that at idle the valve is open but only flows a little bit of air, because the high vacuum actually lifts the piston inside the valve off the seat and up to the top of the valve where it partially closes the exit orifice of the valve. This allows the system to vent but does not introduce enough air to effect the idle to great extent. when the throttle is opened pressure rises to the point where the piston falls to about the halfway point of the valve allowing much more fumes to be vented since the engine will be able to burn them effectively. when the motor back fires or boost comes on(if F.I.) the valve shut to prevent reversion of fumes into the intake. this is where the catch can does the most work because during boost the valve is shut but often leaks allowing boost to go through the valve, combine this with blow-by past the rings and your going to building a lot of crankcase pressure that can't go anywhere with the factory setup because it is trapped between the intake pipe and the manifold. this leads to popped out dipsticks and reduced power from having a boosted crankcase pressure(not much honestly though). When switching to an external pcv intake filter now the crankcase pressure under boost can escape by going backwards through the system all over your engine bay, which is where the catch can comes in. some systems i've seen have valves or solenoids that under boost will vent the catch can to atmosphere and under vacuum allow the pcv system to function normally the below method will allow you to vent crankcase pressure, without contaminating the intake, or reverting fumes all up under your hood, and for an estimated parts cost of 5-25 dollars. And my personal favorite pcv system is the exhaust venturii, no oil stain under the hood, no reversion out the filters from blow by on a boosted car, and i can still imagine myself mystically choking up al gore's air every time i drive. Oh and it's by FAR the cheapest if you can weld or have a buddy who can because it involves two small pieces of tube cut on an angle and roughly 4 ft of hose. (also drilled out factory valves), using seperate pcv filters and plugging the intake pipes and the manifold hoses will allow you to eliminate any source of unmetered air caused by the pcv as well __________________ ANSWER PRICE LIST Answers - - - - - - - - - - - - - - - - $0.75 Answers (requiring thought) - - - - $1.25 Answers (correct) - - - - - - - - - - $12.50 Last edited by 1slow370; 09-29-2013 at 03:52 AM.

09-29-2013, 03:49 AM	#81 (permalink)
1slow370 A True Z Fanatic Join Date: Aug 2009 Location: In the D Posts: 3,732 Drives: v8 74 260z ;) Rep Power: 7251	PCV WIN TWO of these would be the swanky way to do it. __________________ ANSWER PRICE LIST Answers - - - - - - - - - - - - - - - - $0.75 Answers (requiring thought) - - - - $1.25 Answers (correct) - - - - - - - - - - $12.50

09-29-2013, 08:41 AM	#84 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	They shouldn't be unmetered on the stock PCV setup, or any of the intake designs I've seen. None of the connections are in front of the MAFs. Engine vacuum draws from the crankcase, crankcase draws replacement fresh air from the intake tubes, post-MAF. __________________ 7AT Track Car! Journal thread / Car setup details

09-29-2013, 08:54 AM	#86 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Mo' boost mo' problems phunk likes this. __________________ 7AT Track Car! Journal thread / Car setup details

09-29-2013, 10:13 AM	#87 (permalink)
Sh0velMan A True Z Fanatic Join Date: Jan 2012 Location: Dallas/Ft.Worth Posts: 3,349 Drives: Noisily. Rep Power: 20	I have a conceptual design in my head for a PCV/Catch Can setup that wouldn't have the (albeit limited) drawback of drawing unmetered air etc. (For forced induction) I need to get the design on paper, once I do, I'll post it here. G37sHKS and snowsurfdirtx like this. __________________ Buy My Car! \| Build Thread

09-29-2013, 04:19 PM	#88 (permalink)
1slow370 A True Z Fanatic Join Date: Aug 2009 Location: In the D Posts: 3,732 Drives: v8 74 260z ;) Rep Power: 7251	a lot of my previous post wasn't about your car either more of a general discription of pcv's and F.I. and why the stock system needs to be changed for it. So what your saying is by plugging your pcv your idle changed slightly and your letting the computer correct for the small amount of unmetered air entering the manifold, and your very familiar with how pcv works, but are unsure of why pcv valves are on the 370z since it is not factory boosted(this might be where i am misunderstanding you)? Also your inlet hoses for the pcv are plumbed to your compressor inlet pipe instead of those little separate filters right? in that case yeah the pcv will work fine other than the negligible amount of unmetered air, and that everything is still going to get dirty(which most people don't care about. If you hooked your pcv up to the seperate little filters instead tho you would get smokey fumes coming from the filters under boost. Edit: also as a side note i also believe not running a catch can isn't going to cause a problem, they are a waste of money unless you just want everything to stay clean. All of these non issues and minor annoyances is why i like the exhaust pcv fittings, other than the environment there are no downsides, no dirt, doesn't effect the way the motor runs at all, its cheap (just make sure you use high temp hose) __________________ ANSWER PRICE LIST Answers - - - - - - - - - - - - - - - - $0.75 Answers (requiring thought) - - - - $1.25 Answers (correct) - - - - - - - - - - $12.50 Last edited by 1slow370; 09-29-2013 at 04:39 PM.

09-30-2013, 01:56 PM	#89 (permalink)
phunk A True Z Fanatic Join Date: Mar 2009 Location: Chicago Posts: 3,668 Drives: 370 Rep Power: 974723	I have seen the exhaust PCVs used in the past and I agree that they are pretty slick and probably provide superior crankcase vacuum at high engine load where there is none in the manifold. You are correct about how my PCV is running. My VC to IM are stock, and my VC to air filter tubes are unfortunately before the MAF due to blow-through MAF setup. But ya I played with it and it doesn't seem to be flowing enough unmetered air that my feedback cycles for idle and fuel trim cant handle it. Usually all I will do (if needed) to a PCV system for a higher power FI car is enlarge the vents if possible, or add another if needed. My only real argument about why I dont use a catch can "just because" is only about space, organization, clean engine bay, etc. I prefer to eliminate anything in the engine bay that is not needed as, especially with twin turbos, space comes at a premium. __________________ Charles @ CJ Motorsports : Website \| Facebook \| Instagram \| YouTube Home of the 9 second, stock longblock, stock drivetrain 6MT 370z. 9.91 @ 142mph

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