Breather Systems for people who don't know

[prj]

Had no issues over 400hp with properly built engines.
Many problems are caused by failing or semi-failing check valve that sits between the manifold and the breather system.

Many cars that had tonnes of oil going through the breather system had problems with that valve...
If you can blow through it with your mouth both ways, that's a pretty good sign that you need to change it.

Or alternatively, just remove that bit altogether.
(and block off the pipes)

[A80Avant]

check valve always worked on mine

[Ross]

My RS2 covered 80,000 miles with 1.9bar and 365-375hp without any major issue, albeit a couple of breather cleanings and another one well overdue. It's never been on track though, which is where the restrictions in the stock system becomes obvious.

I've driven the past few thousand and it's been fine, but the amount of sticky oil residue that came out of my boost pipes, ISV and throttle body was substantial. That and the issues people have had on track days show there is an issue with the stock system if it's not immaculate...

Seems to me that you can go for varying extremes here:

(1) Full swirl pot & catch tank system with alternate head breather as an ultimate solution. Can use stock head breather position, but should expect a little oil in the catch tank

(2) Swirl pot solution with drain back to sump - should expect a small amount of oil into the inlet tract when tracking it, but a well designed install should minimise this

(3) Rusty's 'suedo' swirl pot that returns to sump via the 30mm breather. A good solution for road use, probably going to lose some oil when tracking it.

Just to confuse things more it looks as if with (2) and (3) you can, depending on position of the swirl pot, blank off the IM inlet and lose both valves or retain both valves and put it on the inlet tract.

Having seen the sudeo pot install pic on Rusty's thread, which looks pretty inconspicuous next to the Inlet Manifold, I'm tempted to go for that. If there is a neat solution that is effectively a t-piece that screws into the sump plug, with a Fumoto valve on the end, I'd go for that. Either way - losing the one-way valves and just venting into the inlet tract seems like a good idea, once one can ensure they're removing most of the oil and returning it to sump.

[Rusty]

Straight line acceleration isn't the problem, it's when combined with high cornering forces that you run into trouble. If you ever fancy track work then you will need to do something to sort the system out, on the road it's just peace of mind and knowing that more of the oil in the sump, which is rather important, stays in teh sump and doesn't end up elsewhere, doing naff all.

[A80Avant]

Straight line accel. Is a problem when your rings are worn!

[prj]

So change rings instead of slapping band-aids onto it.

[Rusty]

indeed.

The real world data I supplied earlier was from g-force related oil problems. If there's something fundamentally wrong with the engine then that does indeed warrant some remedial action of its own.

[macspring]

What I myself have gleaned from the thread so far, purely for my own application I must add, is that if I drive around town as a daily driver, and never track the car - not issue with that as I don't feel the need to do so, and I do the following;

1. Replace the PCV valve 035 103 245A.

2 Replace the N80 valve Part No. ............????

3. Description ...............?. Part No. 034 129 101A ??????

4. Clean properly replace from dealer of some other source, leave out, the "lump" of wire wool. Not sure which one of these options would be the best to opt for ???. Part No. 035 103 477A ???

5. Take off and clean out fully all of the flexible and metal pipe work of the system, and replace any item that's not functioning perfectly as Audi originally intended.

combined with the fact that my engine will be brand new, (rebore, pistons, crank bearings, etc. etc., and say using an RS2 turbo with less than 400bhp, the above steps of 1 to 5 should suffice for me.

Or am I talking rubbish?

If so prefer to be told now. Engine is not finished yet.


If Rusty or JP do suggest a system as per the drawings above, can it be combined with actual photos of the pieces on the workbench before they are fitted, with typed descriptions with arrows on the photos, and some photos of the items fitted to the car, again with arrows and descriptions?


I know it is asking to be spoon-fed, but not all of us, well me anyway, are up to the level of assimilating new ideas through just the written word easily, without accompanying explanatory photos.


It would be an opportunity for someone to assemble the relevant parts for an ABY breather kit and sell on the kit to interested ABY owners on here for a profit ?


Thanks for all of the replies so far.

[macspring]

Slight off topic, what does it mean if when the engine is running and the small blue valve at the rear of the ABY engine is continually clicking ?

Thanks.

[A80Avant]

indeed.

The real world data I supplied earlier was from g-force related oil problems. If there's something fundamentally wrong with the engine then that does indeed warrant some remedial action of its own.

So change rings instead of slapping band-aids onto it.

As far as i am concerned, any car running a bigger turbo and high boost day in and day out, even if it is not tracked, WILL eventually wear the engine parts sooner unless a crankcase system is in place to cope. So, if i change my piston rings and not apply the ' band-aid' then i will get the problem again... not that smart now that, is it?

Everyone has their own opinions. I thought that by stating my bad experience, will enable others to avoid it. And by the way, i have NEVER tracked my car other than once in nurburgring for 4 laps. Sure track cars and jap.drifting cars have the tracking issues more than the actual longterm wear that i am referring to.

Each one can draw their own conclusions...

[mcandmar]

The issue of sucking oil as Rusty describes on high G right hand turns is a real problem, even more pronounced on a 7A motor due to the much smaller baffle plate in the sump. Do a lap of a small 2nd gear roundabout and you can see the plume of smoke out of the exhaust as oil gets sucked in and burnt. This isnt so much an issue with the breather pipework but the design of the block allowing oil to surge up the crank case breather port. I guess this isnt so much of an issue for LHD cars as roundabouts are left hand corners for them.

For a daily driven car i would advise against returning the catch tank to sump. The purpose of a good PCV system is to suck out any water vapour and other contaminants from the crank case on cold starts, last thing you want to do is dump this mixture back into the sump.

[prj]

As far as i am concerned, any car running a bigger turbo and high boost day in and day out, even if it is not tracked, WILL eventually wear the engine parts sooner unless a crankcase system is in place to cope. So, if i change my piston rings and not apply the ' band-aid' then i will get the problem again... not that smart now that, is it?

Everyone has their own opinions. I thought that by stating my bad experience, will enable others to avoid it. And by the way, i have NEVER tracked my car other than once in nurburgring for 4 laps. Sure track cars and jap.drifting cars have the tracking issues more than the actual longterm wear that i am referring to.

Each one can draw their own conclusions...

Sure, a more powerful engine wears out somewhat faster, but the suggestion that it wears out ten times faster is just wrong.
PCP does not rise that much with increased boost, if you have lots of wear, you probably are knocking thus running way too high PCP's.

Get your engine rebuilt to spec and tune your car on a rolling road with proper knock monitoring.
I've boosted stock and tired engines to 1.8-2 bar, and never had issues with excessive oil going out of the breather system unless the engine was very tired and compression in the cylinders was starting to go down a lot - but then those cars would be close to smoking.

I still maintain that for a daily driver, the factory system is adequate, even with big turbos, as long as the clearances and sealing in the engine is fine.
This comes from the experience of tuning dozens of 2.2T cars.

[A80Avant]

Dmitri, after you have tuned the cars, do you stay with the owners for years and know of their engines and their wear?

i too didnt have any blowby when the engine was fresly built for me, so its easy to say that you can tune to 2bar without problems.

hell, i have blowby now and dont see any blue smoke, so my wear is only apparent during boost, so all im saying is that there is a way to avoid wear, so you might as well implement it!

If you are able to get feedback from owners after 10-30-60-100K kms DMitri and you state this above about the tuning and results you have had from the dyno, then...pass