PCV system/ explanation and mod
- Thread starter jimi87-t
- Start date
Does it need to be any sort of special PCV valve or could I just get one in the right size hose off say a NA Honda?
7Mboost;1322617 said:
If you want to keep both the turbo intake and the intake manifold clean while using the stock setup, you would need a catch on both sides.
But like dumbo said, most of your run time is under vac (non boost) so if you only want one, the one between the covers and the TB would filter out more.
Also guys, the more tubing you add will create more restriction, and lessen the PCVs effectiveness. Don't go crazy with the tubing, check valves etc, trying to add a catch can
The one I used was a metal "fuel miser 102" from memory and was -6 barb one end and -8 barb the other so fit my lines perfectly.
Air pumps used for exhaust manifold air injection flow relatively little. The purpose is/was to oxidize residual HC and CO to CO2 and water (steam) in the exhaust manifold. Eventually many manufacturers found that the pulse vacuum produced in the manifold runners as the exhaust valves closed was sufficient to pull air in trhough a lightweight check valve. I believe General Monsters called this "PAIR", Pulse Air Injection Reactor.
In states like NJ, if CO2 in exhaust gas is not close to 14%, the inspectors begin to look for evidence of tampering, which would include dilution of exhaust gas.
BernieK
In states like NJ, if CO2 in exhaust gas is not close to 14%, the inspectors begin to look for evidence of tampering, which would include dilution of exhaust gas.
BernieK
Mk3runner;1318848 said:
Would a methanol/water nozzle placed before the TB effectively clean any potential oil deposits in the intake manifold from the stock PCV setup?
tekdeus;1322669 said:
Or a shot of carb cleaner now and then...Anyways I thought that was the point of a catch can...? Or do you not have one?
IJ, I figured the check valve would be better between the turbo inlet and the catch can in your diagram, then you could get manifold vacum on the crankase? Although I like the idea ending any reverse flow right at the manifold. All and all though, I think your setup is the only properly setup PCV system I've seen on SM. Besides mine:biglaugh:LOL And stockers...But I don't need to tell you that.
Over thinking a simple design:nono:...I'm done haha.
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IJ's diagram is exactly where you want the PCV valve
(you will get manifold vac at all times, except under boost)
(you will get manifold vac at all times, except under boost)
Dumbo: It worked very well as described
I had "issues" with popping the dipstick out at the end of hard pulls without the PCV plumbed in and this cured it 100%.
I had "issues" with popping the dipstick out at the end of hard pulls without the PCV plumbed in and this cured it 100%.
Hear me out,
If you don't put the check valve after the turbo inlet then you can never truly get vacum in your crankcase, atmosphere will simply flow in, correct? No matter the volume "sucking" into your TB(Within reason). That is simply fluid dynamics. If you were popping your dipstick out I guess you have no choice, were your lines and fittings from your catch can to turbo of ample size?
Technically speaking, the stock setup can not put a true vacum in the crankcase either, thats why I put the check valve after the turbo on mine.
If you don't put the check valve after the turbo inlet then you can never truly get vacum in your crankcase, atmosphere will simply flow in, correct? No matter the volume "sucking" into your TB(Within reason). That is simply fluid dynamics. If you were popping your dipstick out I guess you have no choice, were your lines and fittings from your catch can to turbo of ample size?
Technically speaking, the stock setup can not put a true vacum in the crankcase either, thats why I put the check valve after the turbo on mine.
-10 so yep more than big enough
You slam the throttle shut at the end of a hard pull the BoV's take a second to react and this is enough time to have 0 flow into the Turbo so no matter how big the plumbing is you will pressurise the crankcase.
The only concern I had was introducing pirate air into the intake might have affected the idle mixtures and idle speed (it didn't)
Agreed on no vacuum that's why I think a pump plumbed correctly would be a + if you could find one that a) wasn't noisy b) lasted more than 75 miles before needing a rebuild and c) was able to pull a vacuum in a leaky 7M
You slam the throttle shut at the end of a hard pull the BoV's take a second to react and this is enough time to have 0 flow into the Turbo so no matter how big the plumbing is you will pressurise the crankcase.
The only concern I had was introducing pirate air into the intake might have affected the idle mixtures and idle speed (it didn't)
Agreed on no vacuum that's why I think a pump plumbed correctly would be a + if you could find one that a) wasn't noisy b) lasted more than 75 miles before needing a rebuild and c) was able to pull a vacuum in a leaky 7M
I thought about this, until I read that more than 15hg of vac on the crankcase can be bad: http://www.dragstuff.com/techarticles/vacuum-pumps.htmldumbo;1322714 said:
dumbo;1322714 said:
Unless there is pressure in the crankcase, which there always is some....the vac will pull it in the proper direction. The idea is to get crankcase vapor to either the manifold (which is 90% of the time) or to the turbo intake.
Having said that, a check valve on the intake side that only allows flow in the direction of the intake is not going to hurt anything. And, you are correct...the stock style set-up does not put a "pure vacuum" on the cam covers.
7Mboost;1322730 said:IJ excuse me as I will be copying your PCV system.
More than welcome to
I plan on using that same electric pump. Under testing I found that it flows a crap load (exact measurement) of air, and pulls approx 7 inches of vacuum when the intake is blocked off. From what I have read, that is perfect vacuum for a crankcase.
The only problem that I have found is that the pump pulls something like 45 amps of current when first started up, then drops down to around 15 when running. I am planning on running a PCV valve similar to IJ's and then a custom PWM controller to ramp up the power to the pump only under boost.
Here is a link to a previous thread
http://www.supramania.com/forums/showthread.php?t=76560
The only problem that I have found is that the pump pulls something like 45 amps of current when first started up, then drops down to around 15 when running. I am planning on running a PCV valve similar to IJ's and then a custom PWM controller to ramp up the power to the pump only under boost.
Here is a link to a previous thread
http://www.supramania.com/forums/showthread.php?t=76560
jimi87-t;1319044 said:
As pointed out by you and others, you absolutely want to evacuate your crankcase. This is why all cars come with it. I am just glad you all want to do so, rather than just 86 it, like the other "emission devices", of which PCV actually increases engine life by reducing sludge.
A little searching outside of this site my be helpful for some
Summit Racing and other retailers have been selling electric crankcase pumps for some time. Crankshafts cost money, even with a sponsor.
jimi87-t;1319815 said:
Where did you read that? Cars with smog pumps or pulse air are done for the pre cat. Except our car. At least I have never seen Toyota say so. The front cat is for NOx reduction. According to both GM and Ford. Those piece of s*** Chryslers don't count unless it is a Mitsu or Benz.
The precat uses the CO to get rid of the NOx. That gids rid of some of the usable air for the secondary, or main reduction cat. So air is pumped in. What I have seen is switching between pumping air into the head or cat, and sometimes venting. But it will pump to the cat hot and cold.
IJ.;1319524 said:
How you doing old man?
jetjock;1322560 said:
How you doing old man?
Good topic Jimi. I like your work.
tekdeus;1322727 said:
Interesting theory. Although I think that is what the oil pump is for. But I don't want to get into that.
Honestly I don't think I could see that much vacum in the crank with my setup, if you think about the shear volume in there and the size of the TB orifice. Plus at cruise your not pulling as much vacum. I would like to temporalily hook up a vacum gauge and see.
Good point on the BOV IJ, never though about the delay in the opening of it.
Regardless, informative thread, on a system that is grossly misunderstood.:icon_bigg