RS4 PCV System

B6/7 S4/RS4
#16

FWP & Euro, can we agree to play nice in this thread? No jabs, no digs, let’s keep it positive.

I’ve never really had oil consumption issues, per say, but I’ve had plenty of leaks. When I pulled the engine last year, I had oil leaking from the dipstick tube seal, the front main seal, valve covers (even with the new version on the driver’s side), and I was pushing oil past the seals on the coolant pass-through pipes (in the timing case) into the cooling system. I’ve said it before, but I’ll make the claim that positive crankcase pressure is the #1 cause of carbon buildup. If you think about what’s happening when there is positive pressure, that air is moving passed the intake & exhaust valve seals and pushing oil with it. I can’t really make a direct connection to a performance hinderance unless there’s an actual vacuum leak in the system. As Justin mentioned, there is an impact to sealing the rings. That can definitely cause problems…catastrophic problems. This currently has my focus.

[quote=“justincredible,post:13,topic:8291”]
I think you nailed it. This is exactly where I’m going with it.

#17

In euros defence and defense for the others. AZ has lost most of the very technical and knowledgable guys. Now there are way less kooland like guys over there. Most of them are over here. When people like you need real help you get help from guys who are not even close to honest and some have huge agenda. Some of the guys in the past who had issues went out of the way to show what the issues were. like ben or as some call him ben stlie. Ben had issues showed it was carbon but when he wanted to start selling parts and nobody wanted his parts because they were all getting JHM parts ben started changing stories to try and change peoples mind about his parts. You have guys on AZ that are paid to push parts. guys that got disscounts for blowers or other parts in return for glowing reviews and a constant streem of attacks.

I created a RS4 investigation thread here for guys like you. The facts are RS4s are prone to ping stock. When you add the JHM tune your motor rpm goes by faster so you will hear more of the ping as there are more accounts per second. Flashing to stock wont get rid of the ping it will just make it sound less freaquent as the motor rpm is slower. The RS4 invistagation thread and forum investigation shows there are several hundred JHM tuned RS4s but less than >1% have this issue and since this issue is on stock cars as well we have been working to find the issues.

Some guys have found carbon made this happen. Others have found injectors failing caused this issue. People have logged the pinging issue and showed that there is no change in knock so there isnt anything the ecu can see to fix. JHM worked to make a tune to go beyond what the OEM tune did and this is what helps until people find out what the issue is. The thing you obviously see is you have the support of a company that will make a tune to help a mystery hardware issue that can plauge a few guys.

#18

FWP/Koolade, any progress?

I talked to a few guys in the domestic performance world that specialize in aftermarket oil separators and they all agreed that our PCV/oil separator is an overly complicated design.

To simplify the system and reduce maintenance costs, I think replacing the OE PCV with an adjustable and serviceable PCV valve and a separate catch can might be the ticket.

Something like http://mewagner.com/?page_id=444 might work. There’s an in-line adapter for that as well.

I’ve been looking into high quality catch cans as well. There aren’t very many that have overflow valves built in, but I think that would be a good thing to have if we were to replace the stock PCV with it. That would result in a maintenance-free system since it would drain into the crank case. Or we could just plug the PCV drain port and empty the catch can as part of maintenance.

As you guys have discovered, I think the most challenging part will be tuning the air flow into the IM venturi port so the engine idles properly. That and adapting a connector to the venturi port. Edit: adjustable PCV should allow us to meet the target air flow

These are some of the high quality catch can options that may be adaptable to our setup:
https://www.cantonracingproducts.com/product/23-050/23-050----AIROIL-SEPARATOR-TANK--12AN-INLET--OUTLET--14-NPT-DRAIN/#

http://www.mishimoto.com/mishimoto-baffled-oil-catch-can.html

http://www.conceptualpolymer.com/new_page_1.htm

http://www.uprproducts.com/make-your-own-billet-catch-can.html

http://shop.bobsautosports.com/Bare-Bones-Oil-Separator-Bare-Bones-Oil-Separator.htm

http://jlttruecoldair.com/ZenCart/index.php?main_page=index&cPath=378

Once I verify that the Wagner adjustable PCV can achieve the necessary flow rates, which I think it can, I will proceed with purchasing one for testing.

I’d appreciate any feedback.

#19

So Mann+Hummel makes a series of oil separators that look to be better engineered than anything the tuner market produces. They all have easily replaceable filters and integrated oil return valves with an optional check valve. I think the ProVent 400 is a really good option to explore for our vehicles as a replacement oil separator. https://www.mann-hummel.com/fileadmin/user_upload/service/catalogues/pdf/ProVent_en_2013.pdf

I went ahead and ordered the Wagner adjustable PCV and I will perform initial testing with a cheapo catch can so I’m not out several hundred $ if it doesn’t work.

Edit: Maybe the ProVent 400 is overkill for the PCV flow rate of our motor. Any idea what that number might be? The ProVent 200 might be sufficient.

#20

that was a very interesting find. Im going to try and look over that more later

#21

Changing the flow rate of the OE oil separator has a pretty pronounced effect on idle quality. You can try to use an adjustable one to see if you can make it work, but I fear you’ll be restricting total flow capability… The solution I was moving toward was to keep the OE oil separator in place (with the outlet restriction only slightly bored-out). At the elbow that attaches the VC lines to the OE oil separator, split off there and insert a check-valve that’s normally closed when the OE system is under vac, then plumb it to an aftermarket oil separator with oil drain. The suction side will come from the intake elbow post-MAF. This should allow for factory idle, yet give the system the capability to evacuate all of the crankcase air in peak conditions. FWP found a few Subaru applications where they use a dual oil separator to the same effect. (Don’t recall it off the top of my head)

#22

You’re right, the diameter of the piping on the Wagner PCV looks really anemic compared to our system. After speaking with Wagner, they will not release any specific peak volumetric air flow or vacuum numbers. However, they claim their adjustable PCV can flow enough volume for any high displacement v8 street engine and most race engines.

I want to approach this problem with data instead of guesswork so I’m currently trying to locate a blow-by meter. I plan to put this in-line with the PCV system to measure the volumetric airflow.

Koolade, wouldn’t the PCV restrictor and diaphragm be the bottleneck on air flow into the IM? That seems like the most restrictive point in the system. The tubing and PCV have far great volumetric flow up to that point, no? It seems the PCV/Oil separator unit is only as large as it is in order to house the cyclonic oil separator and oil collection/draining components. I haven’t actually opened my PCV up and examined the components, so I may be misinterpreting based on the pictures I’ve seen.

#23

“I want to approach this problem with data instead of guesswork”

Why I love this forum. And this thread.

#24

[quote=“komseh,post:22,topic:8291”]
That’s totally the bottleneck…but when you remove that restriction, your idle goes nuts, you wind up with way more crankcase vac than one would like, and the actual oil separation stops working so you wind up with a very oily intake manifold.

That’s why I’ve shifted to the idea of effectively piggy-backing a second oil separator system, you’re allowing the dynamic loads (where the OE oil separator cannot flow enough) a second path to take. This will also allow the OE unit to operate in it’s optimum efficiency range, which will help keep oil out of the IM. You’re already researching oil separator units, so you’re starting to see the wide range of designs out there. This is about where I stopped looking into it because I got distracted by other projects.

#25

I would like to remove the stock unit altogether. There are several points of failure in the system that are not serviceable: diaphragm, piston, and check valve. It’s no surprise a plastic part is one of the weakest links on the car.

The last couple of times I pulled my IM(when I was dealing with the fluctuating idle) the bank 1 side had a nice layer of oil on it. Carbon seems to build up very quickly on my car as well. This is with a PCV that was replaced less than 10k miles ago.

I’m wondering if the vacuum draw @ idle on the venturi port was modified when I deflapped the IM and plugged the check valve underneath. Any thoughts on whether that might affect how the oil separator works?

I’m gonna pull the PCV this weekend and check out the components in question. Where is the oil drain check valve located?

#26

Koolade and FWP, have either of you tried running the motor with the IM venturi port plugged?

I am considering running the Provent 200 and venting to atmosphere or into an exhaust pipe.

The Provent 200 is on the way. I am pretty confident that it will be able to flow enough gas volume.

#27

The provent has a check valve so you dont get back pull right.

#28

Are you referring to the crankcase breather tube? If so, mine’s been capped for months and the intake elbow has a plug in it.

#29

No I meant where the PCV plugs into the IM.

That is good info though.

#30

Oh, no, haven’t done that yet. Should be fine though if you wanted to try that. The issue with idle and short term fuel trims becomes apparent when too much air is getting through the PCV and into the IM. Right now I’m running a PCV that has its inlet “restrictor” (the part that you can push in with your finger and is spring loaded) drilled out a tiny bit, it’s maybe 2mm larger of an opening than stock. This has resulted in an OK idle and between doing that and having my crankcase breather hose plugged, there is noticeably more vacuum when I open the oil cap, but the idle and fuel trims have been unchanged.

#31

Maybe. There is a pressure regulation valve at the output port that might close if backpressure occurs. This oil separator was designed primarily for diesel engines, which will never have negative crankcase pressure. So that valve might not be designed to account for that condition.

I’ll have it in my hands in a few days so I’ll give it a closer look. If I end up having to plug it into the IM I will just need to make an adapter for that port to have a 1" ID connection. Venting to atmosphere is desirable to me for a few reasons:
Easier
Not a drop of oil vapor from the crank case will be recirculated back into my IM.

#32

I don’t think it would be an issue to cap that IM port. As FWP mentioned, we really only saw a problem when there’s too much air going through the IM. There are several people who say VTA, but I’m not one of them. I’ve seen other cars respond (very favorably) by tying into the intake snorkel vs. venting. Having that slight vac/draw is a good thing. I’d go in between the MAF and the TB. If the provent has a drain fitting, re-purpose the OE drain line since you’re effectively deleting the OE oil separator.

#33

You want some vacuum in the crank case, and if you vent to atmosphere, you’ll actually being created positive pressure which is the exact opposite.

If you’re going to vent to atmosphere and route it through an aftermarket catch can, I’d recommend adding a vacuum pump to the system, GM makes one that is electric and about $75. They are installed in their V8 trucks and vans.

#34

Awesome work guys!!!

I believe in the name of the whole community I can say, thank you! Your research and write ups are worth gold!
Thank you for going the extra mile, doing the research and explaining everything as simple as you do.

I did a carbon clean myself last year and had an idea of how the PCV “should” work when I had everything disassembled and in my hands. Now after reading this thread it’s a whole new perspective mind blown and holy hell did Audi complicate everything.

I remember reading one of koolades post last year where he suspected the PCV as the root cause for drastic carbon build-up in our engines. If you will find a holy grail of improving/removing the PCV I’m in as a guinea pig even if it means shipping parts to Europe.

I have two questions:
1.) Apparently I have a PCV on the way out. After all I read here today, are these symptoms maybe caused by something else (as you actually want more negative pressure from your PCV)?
Symptoms:

  • a small cloud of dark smoke when accelerating;
  • when idling and I open the oil filler cap the engine bogs down a bit and runs in a VERY rough idle at 500rpm;
  • the suction at the filler cap is VERY high;
  • I got a low oil warning, opened filler cap, the light disappeared and oil level was normal. Wtf?!
  • I checked my fuel trim values and they are all fairly within tolerance below +/-10% (taking old fuel injectors into account); they aren’t as extreme as in the first pictures

2.) A stupid question, but just to make sure: I got an O2 MIL, this is probably completely unrelated to the symptoms above?

[quote]008756 - Oxygen (Lambda) Sensor B2 S1
P2234 - 004 - Signal Shorted to Heater Circuit - MIL ON
[/quote]

#35

Check your oil seperator and full PCV system to see if anything looks like its not working.

There is an update to one of the valve covers but I dont think anyone has been able to find out exactly what the update is in the valve cover.

As for the code thats the front sensor on the driver side. That is a main control 02 so you want to keep an eye on it.