How-To: Yet Another Catch Can & CAI Breather Routing (1-2 Cans)

[Gimp]

This is from the "Another Catch Can" HOW-TO. I am posting this a separate HOW-TO so people don't have to go through 8 pages of information to find this stuff.

Below is a result of some research I've done on my own, and through discussions with other members on the best way to route your catch can and lines, specifically on the breather side.

There are two separate configurations; one for the stock airbox and one for a short ram or cold air intake.

Below are pictures and hopefully a good description of what I've come up with.

Photoshop Skills...

I hope this helps everyone understand what I was going for. As a note, I do not run with the airbox lid off. I took it off for pictures.

MAIN DIAGRAM


The top configuration is with the stock airbox.

This has one line that goes:

PCV ---> Catch Can ---> Check Valve ---> Throttle Body (intake manifold)

The second line goes:

Driver's Side Valve Cover ---> Catch Can ---> Nipple on stock airbox

The catch can on the second line is optional.

This should be the best configuration for the stock airbox, and should retain all factory functionality. Notice there is no breather air filter, as the stock foam make-up filter is in the airbox.

The other configuration is with a Cold Air Intake (CAI). This has a few small differences.

The first line is the same as the stock airbox configuration:

PCV ---> Catch Can ---> Check Valve ---> Throttle Body (intake manifold)

The second line is a little different. It goes:

Driver's Side Valve Cover ---> Catch Can ---> Nipple on Intake


Concerns people have about running the breather line into the CAI:

1. You will pull hot, oily crankcase air into the intake track. A catch can will help with the oil accumulation (which can lower the octane rating of your gas and cause the PCM to pull timing), but it cannot do anything about any extra heat that may be picked up from the valve cover.

2. You will be putting the breather side of the crankcase filter under vacuum. In the factory configuration, the breather line is allowed to pull in fresh air. Remember that even though it is in the stock airbox, it is separate from the air filter. When you hook this line up to the CAI nipple, air moving past the nipple creates vacuum and does not allow fresh air to enter the valve cover; it instead pulls hot/oily air out.

DCX Responds to these concerns with the following: - Thanks Breakin Newz

Straight from Darrel Cox..

"Its best to run the PCV thru a check valve to insure it from leaking while under boost.

Next the engine really benefits from the added vacuum under boost if the drivers side of the valve cover is connected back to the air intake. There is alot of vacuum there while under boost.

To insure no oil gets consumed from the air intake you install a recovery tank between the two.

This way when the car is at idle and under no boost the PCV, hence the name (Positive Crankcase Ventilation) keeps vacuum applied to the engine. When the engine is under boost the air intake pulls a vacuum on the crankcase. Bottom line vacuum all of the time. The rings conform to the cylinders better with vacuum. Also ring flutter is minimal with vacuum keeping oil from being pushed by the rings and up onto the top of the pistons and combustion chambers. Out of all of the engines we have disassembled over the years you see it every time (the ones that are not connected to the air intake) also remember that engine oil added into the combustion process greatly reduces the fuels octane. This can causes unwanted detonation and spark knock. The crank seals, valve seals, and cam seals are designed around this vacuum. Also this greatly reduces windage in the crank case further adding proper oil control and some added performance."

ACTUAL PHOTOS W/STOCK AIRBOX

Overall Engine Shot


PCV Side with $20 Catch Can installed


PTP Check Valve and Breather-Side $20 Catch Can


Breather-side routing, top shot; Make-up filter


Breather-side Catch Can, side shot - this is where you can see the breather line running into the stock location (make-up filter)


Make-up Filter inside the airbox


In about a week I will borrow a short ram and get pictures of the proper routing with an aftermarket intake.

Feel free to post questions or comments!

[Breakin Newz]

Straight from Darrel Cox..

Its best to run the PCV thru a check valve to insure it from leaking while under boost. Next the engine really benefits from the added vacuum under boost if the drivers side of the valve cover is connected back to the air intake. There is alot of vacuum there while under boost. To insure no oil gets consumed from the air intake you install a recovery tank between the two. This way when the car is at idle and under no boost the PCV, hence the name (Positive Crankcase Ventilation) keeps vacuum applied to the engine. When the engine is under boost the air intake pulls a vacuum on the crankcase. Bottom line vacuum all of the time. The rings conform to the cylinders better with vacuum. Also ring flutter is minimal with vacuum keeping oil from being pushed by the rings and up onto the top of the pistons and combustion chambers. Out of all of the engines we have disassembled over the years you see it every time (the ones that are not connected to the air intake) also remember that engine oil added into the combustion process greatly reduces the fuels octane. This can causes unwanted detonation and spark knock. The crank seals, valve seals, and cam seals are designed around this vacuum. Also this greatly reduces windage in the crank case further adding proper oil control and some added performance.

This is how I have it hooked up and I like it better then when I had a breather on my valvecover...

[westrock]

I would be hesitant on the "proper" part. There are probably 10 ways you could this. All of them would provide basic funtionality and none of them have been proven to be 100% better then all the rest.

Heck I haven't even see anybody get into using the exhaust as vacuum source on an SRT-4. Then you don't have to worry about where the oil goes

I think poeple should, like you did, read up on all this stuff and see which makes the most sense to them.

I called my thread "Another Catch Can Install" because there were plenty of other threads around....that one reflects my (evolving) interpretation of what should be used. I think I've had 3 different setups in that thread

[ToMuchBoost]

Quote: Originally Posted by Breakin Newz

Straight from Darrel Cox..

Its best to run the PCV thru a check valve to insure it from leaking while under boost. Next the engine really benefits from the added vacuum under boost if the drivers side of the valve cover is connected back to the air intake. There is alot of vacuum there while under boost. To insure no oil gets consumed from the air intake you install a recovery tank between the two. This way when the car is at idle and under no boost the PCV, hence the name (Positive Crankcase Ventilation) keeps vacuum applied to the engine. When the engine is under boost the air intake pulls a vacuum on the crankcase. Bottom line vacuum all of the time. The rings conform to the cylinders better with vacuum. Also ring flutter is minimal with vacuum keeping oil from being pushed by the rings and up onto the top of the pistons and combustion chambers. Out of all of the engines we have disassembled over the years you see it every time (the ones that are not connected to the air intake) also remember that engine oil added into the combustion process greatly reduces the fuels octane. This can causes unwanted detonation and spark knock. The crank seals, valve seals, and cam seals are designed around this vacuum. Also this greatly reduces windage in the crank case further adding proper oil control and some added performance.

This is how I have it hooked up and I like it better then when I had a breather on my valvecover...

I have seen this many places. So it seems the correct way to do it vs the breather.

Original poster: THANKS for taking the time to do a write up

[Gimp]

Thanks to all for the comments.

I edited the title of the post - you are right, proper is not the best phrasing. I was trying to come up with a system that best mimicked the stock system when using a CAI.

I know nothing about vacuum being better on the breather side, so I will default to Darrel Cox. I am using a check valve on the PCV side and a catch can on the breather side to collect any oil that would change the octane rating.

Thanks to all of this, I'm now back up in the air on what to do with my breather side - CAI nipple or it's own breather.........

[RUgoinUp]

Quote: Originally Posted by Gimp

I edited the title of the post...

I took care of the main title change since members aren't able to do so.

[Neipas09]

Which way is the air flowing on the check valve? That might be some good info to know!

[Gimp]

Thanks for the name change!

Quote: Originally Posted by Neipas09

Which way is the air flowing on the check valve? That might be some good info to know!

Air flows from the PCV and into the throttle body/intake manifold. The check valve prevents boost from going the other way.

[you4ic]

So basically the diagram is correct, except the catch can on the PCV side is not needed....right....and the dirvers side of the valve cover goes into a catch can before going to the CAI.....

does this sound right

Quote: Originally Posted by Breakin Newz

Straight from Darrel Cox..

Its best to run the PCV thru a check valve to insure it from leaking while under boost. Next the engine really benefits from the added vacuum under boost if the drivers side of the valve cover is connected back to the air intake. There is alot of vacuum there while under boost. To insure no oil gets consumed from the air intake you install a recovery tank between the two. This way when the car is at idle and under no boost the PCV, hence the name (Positive Crankcase Ventilation) keeps vacuum applied to the engine. When the engine is under boost the air intake pulls a vacuum on the crankcase. Bottom line vacuum all of the time. The rings conform to the cylinders better with vacuum. Also ring flutter is minimal with vacuum keeping oil from being pushed by the rings and up onto the top of the pistons and combustion chambers. Out of all of the engines we have disassembled over the years you see it every time (the ones that are not connected to the air intake) also remember that engine oil added into the combustion process greatly reduces the fuels octane. This can causes unwanted detonation and spark knock. The crank seals, valve seals, and cam seals are designed around this vacuum. Also this greatly reduces windage in the crank case further adding proper oil control and some added performance.

This is how I have it hooked up and I like it better then when I had a breather on my valvecover...

[ToMuchBoost]

Quote: Originally Posted by you4ic

So basically the diagram is correct, except the catch can on the PCV side is not needed....right....and the dirvers side of the valve cover goes into a catch can before going to the CAI.....


does this sound right

Quote: Originally Posted by Breakin Newz

Straight from Darrel Cox..

Its best to run the PCV thru a check valve to insure it from leaking while under boost. Next the engine really benefits from the added vacuum under boost if the drivers side of the valve cover is connected back to the air intake. There is alot of vacuum there while under boost. To insure no oil gets consumed from the air intake you install a recovery tank between the two. This way when the car is at idle and under no boost the PCV, hence the name (Positive Crankcase Ventilation) keeps vacuum applied to the engine. When the engine is under boost the air intake pulls a vacuum on the crankcase. Bottom line vacuum all of the time. The rings conform to the cylinders better with vacuum. Also ring flutter is minimal with vacuum keeping oil from being pushed by the rings and up onto the top of the pistons and combustion chambers. Out of all of the engines we have disassembled over the years you see it every time (the ones that are not connected to the air intake) also remember that engine oil added into the combustion process greatly reduces the fuels octane. This can causes unwanted detonation and spark knock. The crank seals, valve seals, and cam seals are designed around this vacuum. Also this greatly reduces windage in the crank case further adding proper oil control and some added performance.

This is how I have it hooked up and I like it better then when I had a breather on my valvecover...

READ the BOLD RED, a catch can is still a great idea.

[you4ic]

SO...that means a catch can in between the PCV and throttle body or in between the driver side valve cover to CAI? or both? I'm sure this is confusing

Quote: Originally Posted by Stage2BlackSRT4

Quote: Originally Posted by you4ic

So basically the diagram is correct, except the catch can on the PCV side is not needed....right....and the dirvers side of the valve cover goes into a catch can before going to the CAI.....


does this sound right

Quote: Originally Posted by Breakin Newz

Straight from Darrel Cox..

Its best to run the PCV thru a check valve to insure it from leaking while under boost. Next the engine really benefits from the added vacuum under boost if the drivers side of the valve cover is connected back to the air intake. There is alot of vacuum there while under boost. To insure no oil gets consumed from the air intake you install a recovery tank between the two. This way when the car is at idle and under no boost the PCV, hence the name (Positive Crankcase Ventilation) keeps vacuum applied to the engine. When the engine is under boost the air intake pulls a vacuum on the crankcase. Bottom line vacuum all of the time. The rings conform to the cylinders better with vacuum. Also ring flutter is minimal with vacuum keeping oil from being pushed by the rings and up onto the top of the pistons and combustion chambers. Out of all of the engines we have disassembled over the years you see it every time (the ones that are not connected to the air intake) also remember that engine oil added into the combustion process greatly reduces the fuels octane. This can causes unwanted detonation and spark knock. The crank seals, valve seals, and cam seals are designed around this vacuum. Also this greatly reduces windage in the crank case further adding proper oil control and some added performance.

This is how I have it hooked up and I like it better then when I had a breather on my valvecover...

READ the BOLD RED, a catch can is still a great idea.

[ToMuchBoost]

Quote: Originally Posted by you4ic

SO...that means a catch can in between the PCV and throttle body or in between the driver side valve cover to CAI? or both? I'm sure this is confusing

Quote: Originally Posted by Stage2BlackSRT4

Quote: Originally Posted by you4ic

So basically the diagram is correct, except the catch can on the PCV side is not needed....right....and the dirvers side of the valve cover goes into a catch can before going to the CAI.....


does this sound right

Quote: Originally Posted by Breakin Newz

Straight from Darrel Cox..

Its best to run the PCV thru a check valve to insure it from leaking while under boost. Next the engine really benefits from the added vacuum under boost if the drivers side of the valve cover is connected back to the air intake. There is alot of vacuum there while under boost. To insure no oil gets consumed from the air intake you install a recovery tank between the two. This way when the car is at idle and under no boost the PCV, hence the name (Positive Crankcase Ventilation) keeps vacuum applied to the engine. When the engine is under boost the air intake pulls a vacuum on the crankcase. Bottom line vacuum all of the time. The rings conform to the cylinders better with vacuum. Also ring flutter is minimal with vacuum keeping oil from being pushed by the rings and up onto the top of the pistons and combustion chambers. Out of all of the engines we have disassembled over the years you see it every time (the ones that are not connected to the air intake) also remember that engine oil added into the combustion process greatly reduces the fuels octane. This can causes unwanted detonation and spark knock. The crank seals, valve seals, and cam seals are designed around this vacuum. Also this greatly reduces windage in the crank case further adding proper oil control and some added performance.

This is how I have it hooked up and I like it better then when I had a breather on my valvecover...

READ the BOLD RED, a catch can is still a great idea.

Just like the How-TO at the top of the page. But if you have CAI keep it attached instead of useing a breather. Pretty basic

[you4ic]

Quote: Originally Posted by Stage2BlackSRT4

Quote: Originally Posted by you4ic

SO...that means a catch can in between the PCV and throttle body or in between the driver side valve cover to CAI? or both? I'm sure this is confusing

Quote: Originally Posted by Stage2BlackSRT4

Quote: Originally Posted by you4ic

So basically the diagram is correct, except the catch can on the PCV side is not needed....right....and the dirvers side of the valve cover goes into a catch can before going to the CAI.....


does this sound right

Quote: Originally Posted by Breakin Newz

Straight from Darrel Cox..

Its best to run the PCV thru a check valve to insure it from leaking while under boost. Next the engine really benefits from the added vacuum under boost if the drivers side of the valve cover is connected back to the air intake. There is alot of vacuum there while under boost. To insure no oil gets consumed from the air intake you install a recovery tank between the two. This way when the car is at idle and under no boost the PCV, hence the name (Positive Crankcase Ventilation) keeps vacuum applied to the engine. When the engine is under boost the air intake pulls a vacuum on the crankcase. Bottom line vacuum all of the time. The rings conform to the cylinders better with vacuum. Also ring flutter is minimal with vacuum keeping oil from being pushed by the rings and up onto the top of the pistons and combustion chambers. Out of all of the engines we have disassembled over the years you see it every time (the ones that are not connected to the air intake) also remember that engine oil added into the combustion process greatly reduces the fuels octane. This can causes unwanted detonation and spark knock. The crank seals, valve seals, and cam seals are designed around this vacuum. Also this greatly reduces windage in the crank case further adding proper oil control and some added performance.

This is how I have it hooked up and I like it better then when I had a breather on my valvecover...

READ the BOLD RED, a catch can is still a great idea.

Just like the How-TO at the top of the page. But if you have CAI keep it attached instead of useing a breather. Pretty basic

so if this setup holds true, then which catch can is mostly required.....oil getting into your throttle body, or into your CAI (eventually through turbo)

which setup would DCR suggest?
Not many people have 2 catch cans....

[Gimp]

If you are only going to use one catch can, put it on the PCV side.

It is better, and pretty easy to use two.

[gt5oh]

Follow the pictures. The main source of oil comes from the PCV side.

a 2nd catch can is desired but not required from the drivers side of the valve color

all in all, follow the pics, i believe this is the best way for people who keep the stock airbox