PCV/Catch Can/Crank Pressure

**qwkgto** · 02-02-2009, 01:27 PM

Originally Posted by 0rion

you can make do with an inline water filter for air compressors. Not the optimum set up but it'll work.

yep thats the same thing I did,ran it down under the battery tray could not see it,worked great only cost me $20bucks

**Dr.Crash** · 03-12-2009, 10:16 PM

this is a great write up!

**Sarge** · 03-13-2009, 04:00 AM

Information sharing is why we are all here. Well....that and the titties.

**qwkgto** · 03-13-2009, 04:33 AM

Originally Posted by qwkgto

yep thats the same thing I did,ran it down under the battery tray could not see it,worked great only cost me $20bucks

maybe I should post up my old setup bascially oil seperator from lowes/parts store one they use on air compressors,and two barbed fittings 3/8 pipe on one end to screw into filter,and a few feet of 3/8 rubber line.simple and sweet works just as well at that $100 shiny ones.

**Dr.Crash** · 03-13-2009, 07:11 AM

Originally Posted by Sarge

Information sharing is why we are all here. Well....that and the titties.

how could i forget!!!!

**fxgs** · 03-16-2009, 01:04 PM

Originally Posted by Sarge

Information sharing is why we are all here. Well....that and the titties.

Quick question Sarge, regarding the brake vacuum canister, is there a particular reason you ran the vacuum canister as far from the brake booster as you did?

**Sarge** · 03-16-2009, 02:37 PM

No place too put it any closer. Under/over/sides////

**fxgs** · 03-17-2009, 10:18 AM

Sarge, any comment on this, regarding breathers when deleting pcv.
This was a statement posted from another section:

"the reason breathers arent the best or looked favorably with the ls1s is that it introduces unmetered air into the system."

(P.S. Here's some titties for you..................

)

**Sarge** · 03-17-2009, 12:07 PM

Appreciate the tits for sure.
Yeah I hear that crap all the time. Un-metered air.....we'll lets see here.....
Piston goes up and compresses air/fuel....it goes kaboom.....and out the exhaust...right? Well sorta....not all of it does.....you get some blow by passed into your crank (yes you do

)....then the piston goes down and forces pressure into your crankcase.....now the GM smart boys said hey let's recirculate that back into the intake...we be smart as hell!

So they rigged a hose from the valley to the intake tract.....and this is metered how? If your argument is the MAF I aint gonna buy that as the MAF reads not only air flow but air pressure and is calibrated for the PCV....if it is there or not.....
Few issues with the stock setup.....Firstly we all know about oil mist/condensation being sucked back into your intake.....Secondly the pressure in the crank does not allow your rings to seal as good as with the pressure removed (vented)......and you do get resistance to the piston on the down stroke....so we put breathers on to vent the pressure and route the valley tube through a filter and then back to the throttle body.....
I think some of the "un-metered air" folks also sometimes are talking about when you decelerate you do suck some air back into the crank via the filtered vent....OK....little silicon may show up in your UOA.....never been a issue and I submit it is less than a K&N filter anyway.......
So after a kabillion tuning sessions with a gazillion LSX motors running MAFS...I have yet to see a negative from a vent/catch can/
I have only seen positives.

**shady milkman** · 03-17-2009, 12:14 PM

Originally Posted by fxgs

Sarge, any comment on this, regarding breathers when deleting pcv.
This was a statement posted from another section:

"the reason breathers arent the best or looked favorably with the ls1s is that it introduces unmetered air into the system."

(P.S. Here's some titties for you..................

)

**fxgs** · 03-17-2009, 12:20 PM

Originally Posted by Sarge

Yeah I hear that crap all the time. Un-metered air......................after a kabillion tuning sessions with a gazillion LSX motors running MAFS................I have yet to see a negative from a vent/catch can/I have only seen positives.

One last question, if I may, regarding the brake vacuum canister set-up....
one hose runs from the booster to the canister, where are you running the other one from?

**Sarge** · 03-17-2009, 12:37 PM

Back side of the passenger head.....

**shady milkman** · 03-17-2009, 01:02 PM

Originally Posted by Sarge

Appreciate the tits for sure.
Yeah I hear that crap all the time. Un-metered air.....we'll lets see here.....
Piston goes up and compresses air/fuel....it goes kaboom.....and out the exhaust...right? Well sorta....not all of it does.....you get some blow by passed into your crank (yes you do

)....then the piston goes down and forces pressure into your crankcase.....now the GM smart boys said hey let's recirculate that back into the intake...we be smart as hell!

So they rigged a hose from the valley to the intake tract.....and this is metered how? If your argument is the MAF I aint gonna buy that as the MAF reads not only air flow but air pressure and is calibrated for the PCV....if it is there or not.....
Few issues with the stock setup.....Firstly we all know about oil mist/condensation being sucked back into your intake.....Secondly the pressure in the crank does not allow your rings to seal as good as with the pressure removed (vented)......and you do get resistance to the piston on the down stroke....so we put breathers on to vent the pressure and route the valley tube through a filter and then back to the throttle body.....
I think some of the "un-metered air" folks also sometimes are talking about when you decelerate you do suck some air back into the crank via the filtered vent....OK....little silicon may show up in your UOA.....never been a issue and I submit it is less than a K&N filter anyway.......
So after a kabillion tuning sessions with a gazillion LSX motors running MAFS...I have yet to see a negative from a vent/catch can/
I have only seen positives.

that is all gravy ..i have no problem with catch cans..good catch cans like revextremes and Saikou Michi's ...that actually filter the air are great..i just have a problem with breathers since the pcv system is closed and has a vacuum..anything opening up that syytem will cause a moderate vacuum leak...(the reason why no one ever can tell the difference is because the pcm can adjust the a/f to compensate ..so most will never be able to tell the difference...where the problem lies is that the cushion for other vacuum leaks or any other abnormal event where fuel needs to be added is severally limited..with those kabillion tunning sessions i am sure you have seen the a/f ratio shoot around when a breather was installed ..and then uninstalled ...of course a pcm can be tuned for the breather and you might never be able to tell...but the pcv system will be open and suffer in efficiency..and as you know without that vacuum those harmful gasses will be hard on the oil leading them to be changed more often..not quite a problem since most change in 3k....i have been playing around with my pcv and reading up on the pcv system for the past month seeing what my options are for changing. ...the air is metered ..if it wasn't then why would any pcv leak cause the a/f to jump and the car to idle higher/act funny

**Sarge** · 03-17-2009, 03:11 PM

Shady!!!! Think about what you just said.
You are saying the PCV system is sealed vacuum?
Come on man!!!!!!

**shady milkman** · 03-18-2009, 08:38 AM

Originally Posted by Sarge

Shady!!!! Think about what you just said.
You are saying the PCV system is sealed vacuum?
Come on man!!!!!!

i thought i said its a closed system ?

**shady milkman** · 03-18-2009, 08:57 AM

i am sorry the pcv doesnt create its own vacuum its engine vacuum ..sorry if i posted otherwise since i did not mean too

**shady milkman** · 03-18-2009, 09:11 AM

hmm well lets simplify this...for best operation if your going to slap a breather on you better get it tuned..and secondly you shouldnt need a breather with a good/properly set up catch can.

**6.0LiterImportEater** · 03-18-2009, 10:25 AM

I see that the breather that is mentioned is for LS1/LS6 applications. I have an LS2, will this work? If not does anybody know where I can find one for a LS2? Thanks!

**6.0LiterImportEater** · 03-18-2009, 10:31 AM

Oh yea regarding what Shady has posted.......

Manifold vacuum, or engine vacuum in an internal combustion engine is the difference in air pressure between the engine's intake manifold and Earth's atmosphere.

Manifold vacuum is an effect of choked flow through a throttle in the intake manifold of an engine. It is a measure of the amount of restriction of airflow through the engine, and hence of the unused power capacity in the engine.

*Cough, Cough* Vacuum sucks! Only time I care about vacuum is when your brakes work off of it!!! Your A/F ratio does jump up by why need the tune? You eliminated restriction or choked flow thus more air into your engine which also needs more GAS! A/F should go up! Thanks to smart ECM's you don't need a tune!! It's such a small modification that your ECM should be able to correct itself no problem. Now once you starting adding more modifications (i.e. headers, exhaust, pulleys, intake manifold, heads, CAI, etc...) then a tune is probaly required.

Don't pay for tuning either! A Dyno does not mimic "true" factors (rolling forces, drag, etc...). If you have a tuner (i.e. Diablo Sport) just rip it at a track (best case scenario) or a good open road and make your adjustments after each run! Cheap, easy, and better results! NHRA teams tune on the track and not in a shop!

^Best for N/A applications. If you are boosted and just finished your install then a Dyno is probaly the best thing unless you know what your doing! Unless you get a base map from the manufacturer

!

**shady milkman** · 03-18-2009, 11:38 AM

Originally Posted by 6.0LiterImportEater

Oh yea regarding what Shady has posted.......

Manifold vacuum, or engine vacuum in an internal combustion engine is the difference in air pressure between the engine's intake manifold and Earth's atmosphere.

Manifold vacuum is an effect of choked flow through a throttle in the intake manifold of an engine. It is a measure of the amount of restriction of airflow through the engine, and hence of the unused power capacity in the engine.

*Cough, Cough* Vacuum sucks! Only time I care about vacuum is when your brakes work off of it!!! Your A/F ratio does jump up by why need the tune? You eliminated restriction or choked flow thus more air into your engine which also needs more GAS! A/F should go up! Thanks to smart ECM's you don't need a tune!! It's such a small modification that your ECM should be able to correct itself no problem. Now once you starting adding more modifications (i.e. headers, exhaust, pulleys, intake manifold, heads, CAI, etc...) then a tune is probaly required.

Don't pay for tuning either! A Dyno does not mimic "true" factors (rolling forces, drag, etc...). If you have a tuner (i.e. Diablo Sport) just rip it at a track (best case scenario) or a good open road and make your adjustments after each run! Cheap, easy, and better results! NHRA teams tune on the track and not in a shop!

^Best for N/A applications. If you are boosted and just finished your install then a Dyno is probaly the best thing unless you know what your doing! Unless you get a base map from the manufacturer

!

i never said the pcm couldnt adjust and handle it..but then you loose some of the pcm's ability to adjust for other abnormal events..its better to be safe then sorry..a properly functioning pcv system with a FUNCTIONAL(key there) catch can will eliminate any oil/gases getting recirculated..and relieve excess pressure