[BbySnke]

Hello all, it’s been awhile for me. To quickly catch up, my car is running strong and healthy with the BWS turbo, and just recently made the switch back to 91 octane from E85. It is time for some general maintenance, inspections and cleaning.

My main topic is regarding the PCV and drivers side valve cover outlet. For as long as I know this has been an ongoing discussion for many years. I’ve seen DCR’s write up on how these engines need vacuum under boost via the drivers side port being hooked up to the air intake, and I’ve also seen another post where it’s the opposite, stating to remove the line and replace it with a breather filter. Also, I am aware that our factory PCV valves leak a little bit under boost. Since I cannot find a solid answer, my question is what is the best and only way to have it properly hooked up in 2022?

My setup is pretty much factory form. I have the original pcv valve running down to a Catch can, then a Bwoody check valve in between the catch can and throttle body. The drivers port of the valve cover is hooked up directly to my Air intake. Does the factory PCV need to be gutted and put a good working check valve right after the factory one to prevent crankcase pressure? Please let me know if anything is out of the line.

 

[AlmightyFork]

Looks good to me. I personally run a breather on the drivers side as aftermarket intakes are missing the sponge found in the factory airbox. If meth will damage a turbo wheel, oil might as well. I'm considering adding the agp breather catch can.

 

[BbySnke]

Looks good to me. I personally run a breather on the drivers side as aftermarket intakes are missing the sponge found in the factory airbox. If meth will damage a turbo wheel, oil might as well. I'm considering adding the agp breather catch can.

Does your aftermarket intake have a port to run tubing from the drivers valve cover vent to that port?
To my knowledge, that tube that runs to the sponge in the factory air box, might actually be getting a small amount of vacuum from the intake filter (vacuum from turbo) since the air box is closed up. That has me thinking that the drivers port does need vacuum to suck out crankcase vapors and pressure, however with the aftermarket intakes having a port that connects directly the valve cover, there’s no filter to stop oil and vapors going into the turbo.

 

[AlmightyFork]

Does your aftermarket intake have a port to run tubing from the drivers valve cover vent to that port?
To my knowledge, that tube that runs to the sponge in the factory air box, might actually be getting a small amount of vacuum from the intake filter (vacuum from turbo) since the air box is closed up. That has me thinking that the drivers port does need vacuum to suck out crankcase vapors and pressure, however with the aftermarket intakes having a port that connects directly the valve cover, there’s no filter to stop oil and vapors going into the turbo.

Yes, my agp 3" cai has the port. It was a different diameter than the driver breather. I've covered it with a rubber nipple.

Edit: I want to add that I believe that vacuum is unnecessary as the crankcase will undergo positive pressure. Maybe I'm wrong, but I don't worry about it. No oil hitting my compressor wheel please.

 

[BbySnke]

Yes, my agp 3" cai has the port. It was a different diameter than the driver breather. I've covered it with a rubber nipple.

Edit: I want to add that I believe that vacuum is unnecessary as the crankcase will undergo positive pressure. Maybe I'm wrong, but I don't worry about it. No oil hitting my compressor wheel please.

And that’s what I don’t like about the drivers port, is oil going to the turbo and potentially causing knock.

On the PCV valve, do you have a stock one?

 

[tbagg1ns]

I run a dual can setup. Not the prettiest....but gets the job done. It definitely catches a bit. Nice blue btw

 

[AlmightyFork]

Ignore the torn apart dash. Work in progress.

 

[BbySnke]

I run a dual can setup. Not the prettiest....but gets the job done. It definitely catches a bit. Nice blue btw

View attachment 150188

Looks good I’ve been thinking about a dual setup as well. Thanks I think blue is the best color on thrse

View attachment 150189
Ignore the torn apart dash. Work in progress.

I’m still debating whether to add a breather or not. I feel like the crankcase does need some sort of vacuum for pressure withdrawal. I might even have to test it both ways.
I see you don’t have a timing belt cover, you should get one!

 

[tbagg1ns]

I feel like the crankcase does need some sort of vacuum for pressure withdrawal.

I've heard this as well, but I know tons of ppl run a breather or vented can there...

 

[fixit]

fwiw.. my updated build with higher boost @ redline caused additional crank pressure and popped out the front main seal..

simple fix, gut and cut off the top of the pvc, and put a 1/2" elbow (pvc or abs) to a 3/4" heater hose to the catch can of your choice ( beer can ?)

 

[AlmightyFork]

I see you don’t have a timing belt cover, you should get one!

Bah humbug! Lol, maybe a clear one one day.

 

[AlmightyFork]

I've heard this as well, but I know tons of ppl run a breather or vented can there...

How does the PCV work?

 

[fixit]

pre emission car's vented oil fumes (and exhaust gas that gets pass the piston rings) out of the oil breather cap to atmosphere
post emissions takes those fumes into the intake air stream to be burned.
racers typically don't like this because it can foul the plugs and cause knock

 

[BbySnke]

A catch can in between the drivers vent and intake would be a good choice, pulls pressure while catching vapors/fumes. Maybe mounting it down below near transmission so gravity can do its thing.

 

[stage5]

So is it best to add the check valve in between the PVC and the catch can or between the catch can and TB?

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[AlmightyFork]

So is it best to add the check valve in between the PVC and the catch can or between the catch can and TB?

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Between catch can and tb so boost doesn't pressurize the can.

 

[BbySnke]

Read this guys…

How-To: Yet Another Catch Can & CAI Breather Routing...

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...

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