PCV Modification and Education Thread

**CorneliusRox** · 09-30-2012 05:39 PM

Thanks Shane. I was waiting for you to chime in. I should throw you in to the OP too!

EDIT: Done

**mec** · 09-30-2012 08:21 PM

Bunch of good info! Best thing I learned is I have my catch can routed wrong lol. The port closest to the firewall goes on the top and the one closes to the grille goes to the side, so I definitely need to swap those around, then I will delete that rear pcv and avoid getting more oil into my new intercooler :) Thanks guys

**DRAKLORE** · 09-30-2012 10:23 PM

I think the Catch can routing is dependent mostly on design, like the vortex can and others differ from those with baffles?'

And thanks Corey :)

**jrtrainor** · 10-01-2012 04:09 PM

OK so To recap for someone running an RAI Catch Can I would need to make the following changes to fully take care of my system.

1. Make a plate out of a tin can to block the larger hose on the rear PCV.
2. Vent the smaller hose on the rear PCV to atmosphere with a small filter.
3. Disconnect the hose farthest from the front of my engine on the intake PCV and somehow block that hole on the billet plate and then put a filter on the end of that hose allowing it to vent to atmosphere.
4. Finally can i leave the RAI CC to recirculate like it was originally designed? I can take a picture and label what im talking about but the GF took the car to work today so I would have to post it up in a couple hours.

I lied here is my setup on the intake side. The rear side is completely stock so no need posting that image.

**DRAKLORE** · 10-01-2012 04:25 PM

JrT, if you eliminate the large Rear PCV. And vent anywhere in your catch can (preferably upstream) to atmosphere, that should be essentially everything you need.

See you can leave all your catch can hoses intact, but because your eliminating the rear PCV you need someplace for that pressure to go (which means no longer into your intake!)
So adding a "T" fitting and a small filter, or tapping the top of your catch can and adding something similar to this:

^BSH RACE CAN^

Will net you a very good system that will be low maintenance, and almost no carbon build up

**jrtrainor** · 10-01-2012 08:45 PM

Originally Posted by DRAKLORE

JrT, if you eliminate the large Rear PCV. And vent anywhere in your catch can (preferably upstream) to atmosphere, that should be essentially everything you need.

See you can leave all your catch can hoses intact, but because your eliminating the rear PCV you need someplace for that pressure to go (which means no longer into your intake!)
So adding a "T" fitting and a small filter, or tapping the top of your catch can and adding something similar to this:

^BSH RACE CAN^

Will net you a very good system that will be low maintenance, and almost no carbon build up

So blocking the back pcv causes extra pressure so leaving the piping as is now all i would have to do is put a vent on the top of my can. Why leave the piping back into the intake. and why leave the third connection (top connection in my picture) connected. Isnt that dumping oil into the intake? Causing the "almost" no carbon buildup.

Edit: God i feel like such a noob still and ive learned so much but this simple f'ing solution seems complicated to me wtf

**DRAKLORE** · 10-02-2012 03:18 AM

that top connection, doesnt come from or go to the intake... it comes from the block, and routes the pressure to the head.
In normal operations that pressure is then routed back into the intake, carrying oil vapor with it and causing carbon buildup..
So by blocking the rear PCV you eliminate its path to the intake tract, but now you have a pressure builup issue with the potential for blowing seals.
to eliminate this from happening, you need to at some upstream point (a point where the vapor/pressure is cleanest) put an atmospheric vent.

My vote would be the top of the catch can, but it could be a T anywhere in that system, you could even run a rubber hose from the rear pcv port with a tiny filter attached.

I hope thats easier to understand.

Shane Drake

**jrtrainor** · 10-02-2012 09:55 AM

Originally Posted by DRAKLORE

that top connection, doesnt come from or go to the intake... it comes from the block, and routes the pressure to the head.
In normal operations that pressure is then routed back into the intake, carrying oil vapor with it and causing carbon buildup..
So by blocking the rear PCV you eliminate its path to the intake tract, but now you have a pressure builup issue with the potential for blowing seals.
to eliminate this from happening, you need to at some upstream point (a point where the vapor/pressure is cleanest) put an atmospheric vent.

My vote would be the top of the catch can, but it could be a T anywhere in that system, you could even run a rubber hose from the rear pcv port with a tiny filter attached.

I hope thats easier to understand.

Shane Drake

Ah now it makes sense. So I leave my catch can as is routing wise.

I put a filter on top of the catch can.

Block off the larger rear Pcv with a plate

Run a small filter on the port next to the larger rear Pcv hose. And I'm done. No more oil gunk is entering my intake.

**CorneliusRox** · 10-02-2012 10:23 AM

Originally Posted by jrtrainor

Ah now it makes sense. So I leave my catch can as is routing wise.

I put a filter on top of the catch can.

Block off the larger rear Pcv with a plate

Run a small filter on the port next to the larger rear Pcv hose. And I'm done. No more oil gunk is entering my intake.

Yup, and you are going to want to unhook your intercooler hosing and spray a ton of brake cleaner in there!

**jrtrainor** · 10-02-2012 02:12 PM

Originally Posted by CorneliusRox

Yup, and you are going to want to unhook your intercooler hosing and spray a ton of brake cleaner in there!

to clean out oil residue?

**Flexcj5** · 10-02-2012 02:54 PM

Originally Posted by jrtrainor

to clean out oil residue?

Yep, drain the IC's then clean them well. Make sure you let everything dry out well before hooking them back up.

**NorcalPB** · 10-02-2012 03:32 PM

Nice! Reminds me of what I did...it doesn't jism oil too bad but if you're running an oiled filter it will turn black after about 2 weeks.

Just a little fun fact, PCVs were actually introduced for tanks so that when crossing bodies of water, they wouldn't suck in water damaging the engine. They were later required on all cars as it does prevent pollution to the environment (by polluting your valves lol)

A friend is building a factory five Cobra with the new 32v 5.0 and while it's catless, he said he's going to keep the PCV because it's illegal without it? I'm pretty sure a catless 5.0 v8 does more damage than a little hose squeezing out oil...

**davvinchi** · 10-02-2012 04:37 PM

Originally Posted by CorneliusRox

Yup, and you are going to want to unhook your intercooler hosing and spray a ton of brake cleaner in there!

You should use carb cleaner instead of brake cleaner

**CorneliusRox** · 10-02-2012 05:02 PM

Originally Posted by davvinchi

You should use carb cleaner instead of brake cleaner

What's the difference other than the fact that one is already in my garage ;-)

**jrtrainor** · 10-02-2012 05:11 PM

Originally Posted by CorneliusRox

What's the difference other than the fact that one is already in my garage ;-)

x2

**davvinchi** · 10-02-2012 05:20 PM

Brake cleaner is a little more volitile and can do bad things to sensors.

**CorneliusRox** · 10-02-2012 07:30 PM

Originally Posted by davvinchi

Brake cleaner is a little more volatile and can do bad things to sensors.

Good point, avoid the MAP! With either.

**DRAKLORE** · 10-02-2012 07:48 PM

I wasn't supposed to clean my MAP with brakleen?!

JFK lol
Anyways I'm glad that some people are actually going to benefit from this information

**Flexcj5** · 10-02-2012 08:23 PM

Finished my carbon clean and full PCV rebuild/delete this weekend.

Breakdown:
- IE valve cover
- 034 catch can (modified)
- rear pcv blockoff
- crankcase pcv routed to catch can
- vc pcv tied into catch can

Block off of large, rear pcv with small hose re-routed.

Valve cover, -10an fitting, large hose routed down to catch and small hose on right from turbo

Catch can and large hose from crank case with T-fitting connected to the VC.

Close up of crank case hose, T-fitting and vc hose

**CorneliusRox** · 10-03-2012 05:52 AM

looks good! welcome to the clean intake group ;-)

**Flexcj5** · 10-03-2012 06:12 AM

Originally Posted by CorneliusRox

looks good! welcome to the clean intake group ;-)

Thanks. Hopefully this second design is a full fix, not another bandaid. I was running the full 034 system before, never blocked rear pcv and still had tons of oil in the intake and smoking under hard pulls.

As of today, no oil in new tb hose, no smoke from exhaust all the way up to 24psi. Vacuum seems to be holding steadier and car runs much smoother.

**CorneliusRox** · 10-03-2012 06:14 AM

Originally Posted by Flexcj5

Thanks. Hopefully this second design is a full fix, not another bandaid. I was running the full 034 system before, never blocked rear pcv and still had tons of oil in the intake and smoking under hard pulls.

As of today, no oil in new tb hose, no smoke from exhaust all the way up to 24psi. Vacuum seems to be holding steadier and car runs much smoother.

It's pretty full proof. It just doesnt meet the emissions that Audi needed to in order to originally sell the car.

**DRAKLORE** · 10-03-2012 11:18 AM

looks good Brad, could we get a better description of the routing for the Catch can. like where the second port is routed to

**Flexcj5** · 10-03-2012 12:39 PM

Originally Posted by DRAKLORE

looks good Brad, could we get a better description of the routing for the Catch can. like where the second port is routed to

No second port. I capped it off with the breather. I can't see a reason to route another hose the way I did it.

The main (large hose) comes off the block/oil separator (used to be the corrugated hose that went to vc from block) and attaches to the CC. I've then T'd the hose from the VC into this main hose running to the CC.

Basically, with all the crankcase pressure headed to one spot and then vented to atmosphere its setup like the old style chevy motors.

**CorneliusRox** · 10-03-2012 12:49 PM

Originally Posted by Flexcj5

No second port. I capped it off with the breather. I can't see a reason to route another hose the way I did it.

The main (large hose) comes off the block/oil separator (used to be the corrugated hose that went to vc from block) and attaches to the CC. I've then T'd the hose from the VC into this main hose running to the CC.

Basically, with all the crankcase pressure headed to one spot and then vented to atmosphere its setup like every old style motor.

You are going to lose the benefit of your catch can this way. You might want to plug that hole you put in the catch can and then put the filter coming off the exit port of it, that way it still catches as much as it can. If not, no big deal. It will still catch a lot because of gravity and the air filter breaking up the oil vapor.

**LoKisSpYdR** · 10-03-2012 01:02 PM

So please correct me if I'm wrong, with respects to the rear PCV, you can:
1 -block off.
2 - install catch can
3 - remove check valve.

What are the +/-'s of each (obviously shane covered the catch can). Thanks.

**ericpaulyoung** · 10-03-2012 01:05 PM

Originally Posted by Flexcj5

No second port. I capped it off with the breather. I can't see a reason to route another hose the way I did it.

The main (large hose) comes off the block/oil separator (used to be the corrugated hose that went to vc from block) and attaches to the CC. I've then T'd the hose from the VC into this main hose running to the CC.

Basically, with all the crankcase pressure headed to one spot and then vented to atmosphere its setup like the old style chevy motors.

This looks perfect, I am going to do exactly the same.
- Eric

**Flexcj5** · 10-03-2012 03:15 PM

The large, over-molded end of this hose fits the oil separator perfectly. It then necks down to a useable size. Autozone keeps them in stock. Dayco part# 86079. This is what I cut to use for the main hose to the CC.

**davvinchi** · 10-03-2012 03:21 PM

Originally Posted by LoKisSpYdR

So please correct me if I'm wrong, with respects to the rear PCV, you can:
1 -block off.
2 - install catch can
3 - remove check valve.

What are the +/-'s of each (obviously shane covered the catch can). Thanks.

Blocking it off prevents air flow to or from the air track going into the turbo. This I turn prevents oil filled air fromthe crank case
On the neg it prevents pressure from escaping through that exit
Catch can catches oil, but not all oil is removed. Most catch can set ups block off the intake manifold to allow recycle of air without the need for check valves or pcv valves. On the neg the stock pcv allows some air to bypass the turbo under low vacuum. This functionality is lost.
Removing the check valve only makes sense if you are blocking it off or if you are running a hose to feed the intake manifold with a check valve and pcv further up. In other words the check valve would be removed only in certain situations.
Ideal would be: no oil in intake, and some way to remove oil from air being vented from the crank case, and some way to send air around the turbo into the intake manifold that is metered and controlled, and to never have boost leaks

**dnice08** · 10-03-2012 04:36 PM

the turbo intake and charged air outlet are not in the correct places.

**CorneliusRox** · 10-03-2012 07:55 PM

Originally Posted by Flexcj5

The large, over-molded end of this hose fits the oil separator perfectly. It then necks down to a useable size. Autozone keeps them in stock. Dayco part# 86079. This is what I cut to use for the main hose to the CC.

I might need this. This fits the same clipping as the OEM oil separator?

**DRAKLORE** · 10-03-2012 08:28 PM

Well I don't see you needing to modify your oil separator hose if you have the stock VC...

Brad and I are working on a complete Rear Pcv Delete kit that will be put on my site most likely, I don't know all the details, but knowing Brad it will be top notch and a great deal...

I just want to see how much interest there is out there for such a kit, as it will include the Plate, and a few twists Nd surprises for a really professional look in your bay.
On top of that, you can pair it with Any catch can, no modification of you catch can, or any of the existing front PCV will be required. So as long as you have our Rear PCV Delete Kit, and a Catch can setup, you will have effectively eliminated 99% of the oil escaping into the Intake tract.

Don't quote me 100% as We are still ironing out the details.
I'm glad he talked to me about this as I think last year I mentioned to Corey about selling the block off plates, just never figured anyone cared or realized that a catch can was only 50% of the solution.

**ericpaulyoung** · 10-03-2012 09:02 PM

A PCV delete kit that vents to atmosphere is a great product idea.
- Eric

**ericpaulyoung** · 10-03-2012 09:03 PM

Shane - you need to come up with an emblem for your company.

**DRAKLORE** · 10-03-2012 09:21 PM

Dude the fact I have a website and that Taylor Cope (one of my BAT B5S4 customers) was awesome enough to make a logo thing for me is crazy haha

I can't believe my site still works, and honestly it's been tough as hell to get a reach out there, not enough people spreading the word.

**CorneliusRox** · 10-04-2012 06:21 AM

Originally Posted by DRAKLORE

I mentioned to Corey about selling the block off plates, just never figured anyone cared or realized that a catch can was only 50% of the solution.

I made this thread not knowing how people would react because a year ago when I first joined this forum and I mentioned I wanted to vent to air and asked if anyone had done it, AZ came down on me telling me I was dumb, and that's terrible for the environment. I am glad that people are using this and not wasting money thinking a catch can will solve everything. I mean they could, but you would need two of them (one for front, one for rear).

Get moving on the delete kit and let me know if you need any help. I can model and even write software that you plug into a CNC mill, you throw in the tool, home it, and it will do the rest.

My suggestion would be to make it similar to a mirror block off plate for a motorcycle.

**Flexcj5** · 10-04-2012 07:32 AM

Originally Posted by CorneliusRox

I might need this. This fits the same clipping as the OEM oil separator?

I looked at it at the parts store, knew the molded rubber end would be perfect and hoped the clipped end might fit, it doesn't. So I cut the clipped end off and cut the hose to the length I needed after attaching it to the separator.

Originally Posted by DRAKLORE

I can't believe my site still works, and honestly it's been tough as hell to get a reach out there, not enough people spreading the word.

Takes years to build a small business. Don't get ahead of yourself. It will work if you stick to a plan.

Originally Posted by CorneliusRox

I made this thread not knowing how people would react because a year ago when I first joined this forum and I mentioned I wanted to vent to air and asked if anyone had done it...

Get moving on the delete kit and let me know if you need any help. I can model and even write software that you plug into a CNC mill, you throw in the tool, home it, and it will do the rest.

I've had my CC vent to atmosphere for 3yrs. If you don't have inspections it doesn't matter.
Block off kit is in the works. I drew everything up in Solid Works yesterday. Test plates are being water jetted next week.