PCV/Catch Can/Crank Pressure

**Sarge** · 04-22-2009, 03:36 PM

Originally Posted by Firebirdjones

That makes no sense to me at all. They were Tee'd from the factory. Shouldn't make a difference which valve cover you picked to run the hose from, or both for that matter, since they converge and head right for the PCV valve as a single hose anyway.

It is after the PCV when it's already a single hose where you are trying to catch the oil before it enters the throttle body, so the hoses before hand wouldn't have anything to do with clean or dirty.

**Lethal Z** · 04-22-2009, 04:36 PM

Ok my question is for sarge. Now I have read through the thread and it has taken a couple of evenings to do so, I don't think I missed anything buts I may have. Going back to page one with regards to RAWPWR3's set up. To me his setup makes sense, for the most part anyway. The bend in the tubing off the throttlebody appears to be capped, correct me if I am wrong. Now the breather in place of the valve cover cap, that may be a little suspect. To me I think that allows unmetered air into the intake. Replace the breather with the oil cap, reconnect the now capped tube off the throttlebody back to the valve cover and that setup seems to me like it would work fine. The intake is sucking through the catch can and the catch can would catch most of the oil or condensation. This is how my setup is and it seems to work just fine. I realize I am not catching everything but I would think like RAWPWER's I should be catching most of it.

**Hi-Po** · 04-22-2009, 05:58 PM

Well, I just ordered my Elite off Mark at KYSpeed. I swear, Im just gonna start handing him my paychecks.

I guess im going to buy the LS6 valley cover. Dont mind taking the intake off, just didnt really wanna spend that extra money. With the catch can, Breather, LS6 valley cover, and mis. stuff I see this being kinda pricey. But I NEED it done, and quickly. Cool, Good write up sarge, I dont think I have any questions. If I do, you will be getting a new post to look read.

**Hi-Po** · 04-22-2009, 06:09 PM

Breather is now purchased. Im already feeling a weight lifting all my shoulders. This problem has been bugging me, wish I did it over the winter.

**shady milkman** · 04-22-2009, 06:35 PM

Originally Posted by Firebirdjones

That makes no sense to me at all. They were Tee'd from the factory. Shouldn't make a difference which valve cover you picked to run the hose from, or both for that matter, since they converge and head right for the PCV valve as a single hose anyway.

It is after the PCV when it's already a single hose where you are trying to catch the oil before it enters the throttle body, so the hoses before hand wouldn't have anything to do with clean or dirty.

if i am not mistaken the clean side rear fitment..is pushing not pulling out vapors... the clean side gets its name..since it pulls fresh air from the side of the throttle body into the clean side..it then pushes into the T fitting along with the dirty side air...goes through the pcv valve and into the intake again ..so if you cap the clean side..it prevents the clean from mixing with the dirty side air and going through the catch can..which is why i kind of laugh when people vent the clean side..since the majority of the vented air is clean air from the throttle body.

**shady milkman** · 04-22-2009, 07:09 PM

a properly working pcv system with a catch can will vent excellent... as will breathers with a tune ....but either keep the system closed like stock..or open..aka pcv delete..running both will highly reduce the system's efficiency...and with breathers you need to change your oil much more often.....i am curious in all seriousness..what gains did you put down with your rings sealing slightly better with breathers.

**Firebirdjones** · 04-22-2009, 07:12 PM

Originally Posted by Sarge

I guess this means I am thinking correctly Sarge????

**Firebirdjones** · 04-22-2009, 07:14 PM

Originally Posted by shady milkman

if i am not mistaken the clean side rear fitment..is pushing not pulling out vapors... the clean side gets its name..since it pulls fresh air from the side of the throttle body into the clean side..it then pushes into the T fitting along with the dirty side air...goes through the pcv valve and into the intake again ..so if you cap the clean side..it prevents the clean from mixing with the dirty side air and going through the catch can..which is why i kind of laugh when people vent the clean side..since the majority of the vented air is clean air from the throttle body.

Now that just really confused the hell outta me

**shady milkman** · 04-22-2009, 07:23 PM

sorry..with that t fitting still installed..your introducing clean air from the throttle body into the dirty tube (the pcv valve hose) ..so with a catch can..why would you want clean..already filtered air to go through your catch can with the dirty air ? is that a little better ?

**Firebirdjones** · 04-22-2009, 07:30 PM

Originally Posted by shady milkman

sorry..with that t fitting still installed..your introducing clean air from the throttle body into the dirty tube (the pcv valve hose) ..so with a catch can..why would you want clean..already filtered air to go through your catch can with the dirty air ? is that a little better ?

But the air doesn't come from the throttle body and move towards the T-fitting. It's the other way around.

Air is sucked through the hose "INTO" and towards the throttle body due to incoming air passing through the throttle body via the air intake system causing a vacuum,,,,so I am simply pulling air through both hoses from the back of both valve covers,,,,into the T-fitting which brings everything down to a single hose,,,,,into a PCV valve,,,then into the catch can where it catches any oil residue before it enters into the throttle body.

I'm pretty sure this is correct and does seem to be working well.

**fxgs** · 04-22-2009, 07:56 PM

Originally Posted by Firebirdjones

I'm pretty sure this is correct and does seem to be working well.

My set-up works fine also (although I will continue to monitor it)
but this discussion is like the Republicans vs. the Democrats...................
they both think they're right

**shady milkman** · 04-22-2009, 08:01 PM

Originally Posted by Firebirdjones

But the air doesn't come from the throttle body and move towards the T-fitting. It's the other way around.

Air is sucked through the hose "INTO" and towards the throttle body due to incoming air passing through the throttle body via the air intake system causing a vacuum,,,,so I am simply pulling air through both hoses from the back of both valve covers,,,,into the T-fitting which brings everything down to a single hose,,,,,into a PCV valve,,,then into the catch can where it catches any oil residue before it enters into the throttle body.

I'm pretty sure this is correct and does seem to be working well.

see if the back passenger side rear fitting has suction..i am pretty sure it is pushing clean air into the dirty air. the front most passenger side fitting goes into the throttle body..and it actually pulls in the clean air from the throttle body..not the other way around.

**shady milkman** · 04-22-2009, 08:14 PM

Originally Posted by fxgs

My set-up works fine also (although I will continue to monitor it)
but this discussion is like the Republicans vs. the Democrats...................
they both think they're right

there are no right and wrong answer..its just under what application and what steps are needed..for example..your system is pcv delete and you are now running two breathers..and got it tuned to accommodate this change..nothing is wrong with that.

**Sarge** · 04-23-2009, 04:56 AM

Originally Posted by shady milkman

if i am not mistaken the clean side rear fitment..is pushing not pulling out vapors... the clean side gets its name..since it pulls fresh air from the side of the throttle body into the clean side..it then pushes into the T fitting along with the dirty side air...goes through the pcv valve and into the intake again ..so if you cap the clean side..it prevents the clean from mixing with the dirty side air and going through the catch can..which is why i kind of laugh when people vent the clean side..since the majority of the vented air is clean air from the throttle body.

You should see the filter full of oil form your "clean side" on my setup and you would change your mind real quick. As you know I had to add a Husky catch can setup on it separately to get the additional venting without blowing oil all over the engine bay.

**Sarge** · 04-23-2009, 04:59 AM

Guys.....I think we are mixing up PCV routing systems. Shady has an old FBody and we dont. I think there is overlap and that is confusing people. Shady the GTO doesn't have the exact same setup as your FBody.

**Firebirdjones** · 04-23-2009, 06:29 AM

Originally Posted by shady milkman

see if the back passenger side rear fitting has suction..i am pretty sure it is pushing clean air into the dirty air. the front most passenger side fitting goes into the throttle body..and it actually pulls in the clean air from the throttle body..not the other way around.

Yes they both have suction, that is what I was trying to explain. Then they T into a single line that runs to the PCV. Then that line runs through the catch can catching any oil residue before it goes back into the throttle body.

Nothing has really changed from the factory setup on mine other than the fact that I added a catch can before it enters the throttle body.
Mine was sucking so much oil that it would pool in the bellow. I got smoke on startup all the time after it had been running and was shut off.
That has since disappeared now that the catch can is in place, so I'm pretty sure it's working.

**Firebirdjones** · 04-23-2009, 06:30 AM

Originally Posted by Sarge

Guys.....I think we are mixing up PCV routing systems. Shady has an old FBody and we dont. I think there is overlap and that is confusing people. Shady the GTO doesn't have the exact same setup as your FBody.

That would explain it I guess. I'm messing with catch cans on a 2000 and a 2002. So I would assume the method I am using is correct???

**Sarge** · 04-23-2009, 07:36 AM

Absolutely.

**shady milkman** · 04-23-2009, 09:15 AM

Originally Posted by Firebirdjones

That would explain it I guess. I'm messing with catch cans on a 2000 and a 2002. So I would assume the method I am using is correct???

a f-body ? 2000s had the same set up..it was the 01's-02s that got the ls6 style pcv system.

**shady milkman** · 04-23-2009, 09:22 AM

Originally Posted by Sarge

You should see the filter full of oil form your "clean side" on my setup and you would change your mind real quick. As you know I had to add a Husky catch can setup on it separately to get the additional venting without blowing oil all over the engine bay.

oil doesn't make the "clean side" dirty..its the crankcase fumes that determines that. its the fact that the clean side gets its name from the clean air coming off the throttle body into the valve cover ..compared to the dirty side..where it doesnt get "injected" with clean air..it gets the used "dirty" fumes and routes it to the pcv valve etc...plus your build is no were NEAR! a stock or mild set up where a breather is not needed...i agree 100% that your build would need that extra ventilation..and you have it set up great. but i would say for 98% of us its overkill to say the least..where a 100 buck catch can is all that is needed..or just a pcv valve change.