Don’t really think there’s anything to worry about with the new redesigned version. Time/abuse will tell… I think everyone’s just worried because no one seems to know exactly what Audi corporate did in the test and redesign of the part. I’m guessing much more than can be seen on the surface.
From my point of view there are a few things that work together that cause both the flaps to break and the intake to coke shut.
Crank case ventilation (Positive) ; this brings gasses that behave as solvents that slowly dissipate into plastics and make them hard and brittle and even expand, into the intake manifold and intake tract, covering valves etc.
Internal EGR; this is deliberate overlap in valve timing that serves two purposes: emissions and reduction of pumping losses at part throttle conditions (fuel economy)
The downside of this is that it also forces slight amounts of exhaust gasses past the intake valves, thus heating everything up.
Combination of the heat and PCV deposits create the black crap we have to remove all the time, and also thick gunk on the flaps that makes some of them turn more difficult or makes it hard to fully shut, which causes them to break even sooner.
My plan; I’ve ordered a spare connector that sits in between the PCV valve assy and the intake manifold, and also a spare plate that sits on top of the block, where the oil from the PCV/separator drains into. This is also where the air enters the crankcase for -positive- venting, via a one way check valve.
I’ll write a tune that eliminates the valve overlap (internal EGR) and I’ll blank the air entry into the top of the block. I’ll also remove the connection between separator and intake manifold and bleed the crank vent to air underneath the car.
It has a few downsides to it, but a huge amount of benefits.
The downsides are more or less: engine needs to get to real operating temperatures in order to really gass-out the water and contaminants from the engine oil, that would have gotten vented way sooner before. Engines have run that way for a century or so, and with good oil change intervals this should be no problem whatsoever.
The environment; sh*t if I would care about that I would drive a prius.
No crankcase vacuum; crankcase vacuum is (believed to) beneficial to low load, high rpm conditions in order to aid ring sealing, and supposedly brings a slight power output gain over all by having all the gear rotating in less dense air.
The oil separator will work less efficiently; the cyclonic separators work best at high flow rates. Removing positive CV really lowers the air velocity and will allow more oil mist to find its way out the engine. With a healthy engine this is negligible, luckily we have auto oil level warning.
yeh. didnt really know which forum to write my ideas/plans but this one was kind of active so there you have it.
I dont get how to edit my previous post… cant find the button, just a quote option.
Anyways I forgot to write why I bought these two spare parts; it’s so i can measure them and make nice blanking plates and an oil separator venting tube, without having to take my intake off. Car is a daily.
I agree. Audi didnt really change anything. They changed the rubber tips on the flaps from what I can see. They went to a softer material. The material change seems to not require a part number change as nothing engeneering wise would have been changed I guess. Audi did this with the timing chain guides on the 4.2 S4. They changed the material used but kept the same part number.
Daandaman welcome to the forum. A few things. the more you post the more privlages you get. So I think editing is at like 150 posts.
As for your idea you posted above. Let me give you a few reasons why thats not a good idea.
1 the intake arms dont break due to getting coked with anything thats not the issue. The mounts are an interference fit over time the mounts brake causing the mount to elevate up putting extra tq on the arms and they snap. So the reason you listed are not why the intakes break.
2 There is no valve cam over lap. Audi removed that a long time ago when the carbon issues started to really show there faces. Audi had manditory updates and if you look at car fax reports any car that went to the dealer ship for anything they got the update.
3 The PCV system is what is keeping the car from getting back flow that you decribed as getting gasses back up stream. That cause issues. The oil separator is one of the best revisions from Audi and if you have a healthy PCV and oil separator you dont need to do anything as it will on its own solve all the issues your trying to solve.
4 remember the carbon issue is not something that comes after a few hundred miles this is the effect people are seeing after 70,000 miles. The intake is an issue not after a few thousand miles but after again 70 or 80,000. So the system on the car works great the real solution is to maintain it and update the parts as needed.
5 IMHO removal or reducing the PCV system is great if you have a 68 Corvette or a 1985 dodge ram. On these 2006 and up ULEV cars they are set up to run better with a vacuated crank case and they do. If you did your idea you would be increaseing the crank pressure as the crank pressure it would only escape under positive pressure when the pressure builds up enough to exceed the outside force acting on it. The current system pulls out the crank case pressure leaving in some cases a negitive pressure that helps seal the rings and helps the ring gap in the upper rpm. It also helps keep the valve cover gaskets and other gaskets happy.
6 kinda lastly the idea of removing the PCV system or too much modification to the system has already been tried and it results in more gasket leaks and almost like a vac leak that causes fuel trim issues.
You also noted that the down side to what you proposed would be more oil getting burnt and that is true. But keep in mind burning oil leaves a nasty oily exhaust charge. Doing so can wipe out the 02s and since 2 of the 4 02 banks require the motor to be pulled to change the o2s. I think its best just making sure the oil separator is separating the oil out of the intake charge.
I do not think anything has changed. The flaps have been blue for years (probably since the rev M version dropped years ago)
Here is a pic from 2 years ago out of another thread on this form
I would say that the delay in shipping new manifolds during the last few months is a result of running out of stock and more had to be manufactured to the rev M specs.
A company the size of Audi is not going to devote valuable engineering resources redesigning a component that was only ever used on a platform that is now 10 years old. The cars are all well out of manufacturer’s warranty now so there is no incentive to put any more R&D into it. They are just reaping the benefits of all the expensive parts sales now.
They got 2K out of me last fall when my rev C manifold started spitting plastic parts out
They have M code in black but the Blue material is also under the M code. I have seen both intakes with black and with blue flaps. The blue material seems softer the black flap tips are harder.
The issue for some is. There are still intakes floating around with the M code and black flap tips. Where apparently the most desirable flap tips are the blue ones.
but yeah Im with you I dont see Audi doing anything new to the intakes. It might have more then likely be a manufacture thing. but they did do a revision on the guide material for the S4 so this might be like that. who knows. So far the blue flaps tend to suggest the intakes are newer.
@eng92 The 2k for the manifold,was that CAN$ or US$? I read that you are east of T.O. and I am an hour west and the cheapest quote I have is $2950.00 plus tax in our canuckbucks.
Trade pricing
How long ago were they using black? I have only ever seen pictures of tan and blue.
At work, we will list allowable material substitutions on our spec drawings which would all carry the same p/n and rev level
Let me look over the pictures I have an check the intake manifold dates from the past few installs Ive helped with here local.
Both my M version intakes were tan. The few C versions I have seen were black. I have only seen the blue on the very recent versions. What’s odd is that paul got his intake before me and it was blue, mine was tan and now others are getting the blue again.
The original “C” version on my 07 S6 had tan flaps and had a date of Sept 20, 2006 on the id label
Hey Justin
Appreciate your feedback. My comments:
1: In my car the variable length flap shafts have some ‘gum’ on them (either it being deposits or reacted plastic compound), which makes them move difficult in the mounts. The mounts are all totally fine. Also on the flaps themselves there are these gunky deposits, and also on the seating areas on the metal is a nice layer of waxy oil vapor deposits. This makes them slide with more difficulty. I think that combined with the brittleness this causes them to sheer.
2: I have not studied the cam timing maps yet but from the technical docs on the BSM engine there should be internal EGR. It would be nice if there is already no overlap in the factory tune. I’m not sure what car fax reports are, but here in the Netherlands, the dealers are not able to tell me what kind of engine management updates have been given to my car.
3: I think you are misunderstanding what I meant there. This is not PCV related. The back flow would be back flow of exhaust gasses through the inlet valves because of possible valve overlap due to internal EGR.
4: There are people reporting early signs of deposits just after a few minutes of hot engine operation. Myself being one of them! Kind of a pain in the ass if you’ve just gone through the effort to cleaning everything and seeing it already starts to come back.
5: We remove PCV all the time from racing engines (also modern ones), and albeit difficult to measure due to the pulsed nature, the pressure in the crankcase with properly gapped rings and reasonable venting facilities is in the milibar range. Personally we have never been able to measure performance gains/losses from running an engine with or without slight crankcase vacuum. If gaskets start to leak because you remove the crank vacuum, the gaskets were to be replaced anyways because you are not supposed to suck in outside air via gaskets.
6: I’ve not seen properly executed PCV deletes on our engines, nor properly documented ones where it harmed head gaskets?? I also can’t quite comprehend how a head gasket should be affected by PCV or vent to air.
About your last remark, I didnt mention more oil would be burned, I said that the vented fumes would contain a larger amount of oil particles. These would be vented to air so would find no way to the inside of exhaust system/cats/O2 sensors.
If all, removing PCV and venting it to air AIDS in preventing that from happening.
Another plus is that you will notice less detonation because oil vapors severely lower octane number of the charge in the cilinder. This is why it is removed from race engines as standard, these are tuned to make the most of the fuel’s octane number and would continuously pull timing due to knock issues with the oil vapor in the air charge.
ps. my cyclonic separator/PCV valve is brand new OEM, and compression/ring seal is top notch, so it is not because of that.
Sounds like there is pretty big demand for an aftermarket solution . Any takers on one that is less than msrp from Audi, what’s he best price out there?
Otherwise just call it an expensive maint item and replace every 50-70k.
Im respoding to your entire post but felt it would be cleaner to just use this text.
To simplify my answer. Your idea of removing the PCV and reduceing or eliminate the oil separator are removing the parts that are there to solve the issue your trying to solve by removing them.
A properly working PCV and oil separator system already do all the things your trying to do. Again keep this in mind. When the carbon is cleaned and the PCV system and oil separator is cleaned and working properly you have to check for carbon build up or muck build up what. Every 40 or 50k realistically its much longer as you see cars with 100k and the carbon build up isnt that bad. These intakes are breaking after 80 or more thousand miles or almost 10 years of use isnt exactly a great reason to fall into panic and pull the PCV system off.
Again removal of the PCV system is more down side than up side. You want to see how your car will run without the PCV system. Simple… try this. Go pull off your oil cap. Thats a quick simple way to bypass your PCV system… now see how your car runs… like crap
30 years ago race teams used to pull off the PCV systems now they DONT pull them off they use EXACTLY what we have on our cars and thats an oil separator and a strong PCV system. The current Audi DTM team has our style PCV set up… Some race teams have a similar style but with a dry sump they might use alternitive methods but they all seem to include a PCV of some sort. Some teams actually run a crankcase vaccum pump to pull even more crank case pressure out. Now if you build a race motor or have a motor that dosent need negitive crank case pressure then go for it. On the 5.2 you want the negative crank case environment as its better for the gaskets. Negitive crank case pressure helps things like the valve cover gaskets and other gaskets seal properly and maintain a good tight seal.
I dont want you to think Im trying to rain on your parade. You seem quite set on taking out the PCV system. and while I think its a terrible idea as In both theory and practice its shown to not work and it rittled with flaws. I just want to make sure to state what we have found out over the years and add some counter thoughts that should be takin into consideration. Several of your assumptions are false or incomplete of possible full perspective.
IMHO if you want to reduce the oil in the intake track. Concentrate on the oil separation system and how to make that better or more efficent. Some RS4 guys have put another oil separator in line with mixed results.
another thing to consider that checks off lots of boxes to keep the intake clean and the valves clean if your worried about it. Take the time and work on a methonal injection system to spray just before the throttle bodys. This is how audi solved this issue on the newer cars. Audi has secondairy injectors that spray before the intake that turn on at crusing speeds.
Your intake manifold looked like it was a reman from the pictures you posted. Do you think that reman versions could be tan and new new ones are blue
Justin, the reason it runs like crap when you take off the oil filler cap is because you are then sucking in unmetered air.
Separator will stay, crankcase venting will no longer be positive and the vented gasses will no longer go into intake charge.
Furthermore we have never experienced any power output changes in between to-air and the mild vacuum of pcv. This is not a drag racing engine where half a percent of gains on the total power output is 30hp.
The only reason pcv exists is because of worldwide emissions laws.
WOW … Do you honestly believe the PCV system only exists due to emmisions… WOW… and with that good luck…your going to need it