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R needs a clutch, replace anything else while it's in the shop?

AceHammer

Ready to race!
Location
NY USA
Car(s)
2015 A3
The stock PCV is effective on a relatively stock car. However, once you start pushing over 28 psi roughly you run the risk of damaging the rubber flap inside of it, breaking it. It also can not keep up with hard cornering on cars with tires and suspension. The stock PCV also contributes to carbon build-up

The oil in an inline catch can, such as APR's is from driving the car hard on boost and overloading the stock valve. Because the car is on boost, this oil is sent down to the turbo inlet into a catch can.

Edit - Hard breaking followed by left-hand turns are worse case scenarios for the stock PCV valve. On just Neuspeed springs and Michellin AS/3+ I was able to overload the stock PCV.

If you look at how the 2-way system works, when you're off boost it vents blow-by directly to the intake, bypassing any inline catch can. This is why when people put inline catch cans on they often see very little in them, as for a majority of their driving the blow-by is being directed directly to the valves, rather than the catch can.
This can contribute to carbon build-up, and is the reason people see smoke at the track even with an APR catch can, as when they come off boost and corner hard, the oil is instead sent to the intake valves, completely negating the catch can.


UYRxBIm.png



The Audi RS3 LMS car and VWR/Spluuen systems removes this functionality and force it to always vent to the turbo inlet hose. The downside of these systems is that they also delete the yellow passages and as a result, they send more oil down the turbo inlet hose to the catch can when driven hard. AKA there is no longer an oil return passage
They function as an old-school 1-way system. If you just drive the car around normally you will have minimal oil in your catch can. However, when you start flogging it, the PCV will now direct that extra oil that would otherwise be returned to the pan, to the catch can. This is still better than having the stock PCV only direct some to the pan and some to your intake air.

The best solution is to run an actual Air/Oil Separator and plump it back down into the oil pan. This gives you the best of both worlds.

No risk of PCV failure at high boost, oil control at high Gs, no unfiltered blowby into valves. It also returns the excess oil back into the oil pan, like the stock system.

There is a forum post detailing about putting in a setup like this, but IMO it's a bit overkill unless you are heavily tracking the car. I beat on my car really f**king hard ie autocross Watkins glen etc. and only empty my can every 1k miles and it's nowhere near full.

edit - I've been drinking a bit and can't spell :p
 
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joedubs

Go Kart Newbie
Following up on this real quick to show why I needed a new clutch. The pressure plate cracked into 3 pieces after doing a light launch at around 4K. It’s a southbend kit so I’m pretty surprised to see this happen. Not sure how many miles we’re on it but couldn’t be more than 50k.
This must have sounded horrendous....
The stock PCV is effective on a relatively stock car. However, once you start pushing over 28 psi roughly you run the risk of damaging the rubber flap inside of it, breaking it. It also can not keep up with hard cornering on cars with tires and suspension. The stock PCV also contributes to carbon build-up

...
Thanks for the write up, that was an awesome explanation!
 

GTIfan99

Autocross Champion
Location
FL
The stock PCV is effective on a relatively stock car. However, once you start pushing over 28 psi roughly you run the risk of damaging the rubber flap inside of it, breaking it. It also can not keep up with hard cornering on cars with tires and suspension. The stock PCV also contributes to carbon build-up

The oil in an inline catch can, such as APR's is from driving the car hard on boost and overloading the stock valve. Because the car is on boost, this oil is sent down to the turbo inlet into a catch can.

Edit - Hard breaking followed by left-hand turns are worse case scenarios for the stock PCV valve. On just Neuspeed springs and Michellin AS/3+ I was able to overload the stock PCV.

If you look at how the 2-way system works, when you're off boost it vents blow-by directly to the intake, bypassing any inline catch can. This is why when people put inline catch cans on they often see very little in them, as for a majority of their driving the blow-by is being directed directly to the valves, rather than the catch can.
This can contribute to carbon build-up, and is the reason people see smoke at the track even with an APR catch can, as when they come off boost and corner hard, the oil is instead sent to the intake valves, completely negating the catch can.


View attachment 205436


The Audi RS3 LMS car and VWR/Spluuen systems removes this functionality and force it to always vent to the turbo inlet hose. The downside of these systems is that they also delete the yellow passages and as a result, they send more oil down the turbo inlet hose to the catch can when driven hard. AKA there is no longer an oil return passage
They function as an old-school 1-way system. If you just drive the car around normally you will have minimal oil in your catch can. However, when you start flogging it, the PCV will now direct that extra oil that would otherwise be returned to the pan, to the catch can. This is still better than having the stock PCV only direct some to the pan and some to your intake air.

The best solution is to run an actual Air/Oil Separator and plump it back down into the oil pan. This gives you the best of both worlds.

No risk of PCV failure at high boost, oil control at high Gs, no unfiltered blowby into valves. It also returns the excess oil back into the oil pan, like the stock system.

There is a forum post detailing about putting in a setup like this, but IMO it's a bit overkill unless you are heavily tracking the car. I beat on my car really f**king hard ie autocross Watkins glen etc. and only empty my can every 1k miles and it's nowhere near full.

edit - I've been drinking a bit and can't spell :p
I installed the BL version of PCV with an inline cc has resolved the smoking issue on track. I do get oil in the cc on track. None on the street.

Several others in here use BM and cc and get oil in the cc on track.
 

AceHammer

Ready to race!
Location
NY USA
Car(s)
2015 A3
I installed the BL version of PCV with an inline cc has resolved the smoking issue on track. I do get oil in the cc on track. None on the street.

Several others in here use BM and cc and get oil in the cc on track.

The BL is the updated one from the S4 and I believe the newest golf Rs. It does 100% handle the oil surge issue better, but there are still reports of people overloading it on competition tires. I don't run tires that aggressive so I can't say for sure first hand.
The oil you see in the cc on the track is from even the updated one being overwhelmed a bit, just not nearly as much. I still guarantee though that on the track with the BL oil is still being burned a bit. There's a reason VW uses a 1 way on all their MQB track cars.

It however still suffers from the same issues as the older ones, as high boost can damage it, and it still vents directly to the intake when you are off boost, hence why I believe that some oil will still be burned.

IMO if your only stage 2 and you are not beating the piss out of it, stick with the stock one on your car.
However, if it is damaged or you are pushing big power / tracking just do a full replacement for the extra 400.


Edit - To addin why I 100% believe that the BL will still be sending oil into your intake is that you are getting oil in the CC on the track. This means under power the BL valve is being overloaded but the oil is being sent to the CC, as the system is in 'boost mode'. When you are braking/cornering off boost, I bet you pull even more Gs and as a result that oil is going straight onto the valves, as the system is in air mode'. Not enough for you to notice smoke out the back, but still.
 
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GTIfan99

Autocross Champion
Location
FL
The BL is the updated one from the S4 and I believe the newest golf Rs. It does 100% handle the oil surge issue better, but there are still reports of people overloading it on competition tires. I don't run tires that aggressive so I can't say for sure first hand.
The oil you see in the cc on the track is from even the updated one being overwhelmed a bit, just not nearly as much. I still guarantee though that on the track with the BL oil is still being burned a bit. There's a reason VW uses a 1 way on all their MQB track cars.

It however still suffers from the same issues as the older ones, as high boost can damage it, and it still vents directly to the intake when you are off boost, hence why I believe that some oil will still be burned.

IMO if your only stage 2 and you are not beating the piss out of it, stick with the stock one on your car.
However, if it is damaged or you are pushing big power / tracking just do a full replacement for the extra 400.
I'm stage 1 and autocross and track on 200tw tires. BL and a CC solved my issue.

Totally agree if your pushing big power, the fractory pcv isn't adequate, but it is for street cars stage 2 or less.

Tracking stg 2 or less, BL with cc seems to do the trick and it's 160 plus 50 for a cheap cc and decent lines.

If I were running 100tw or less tires, I'd likely switch, but again, I think this is a VW forum where 99% don't autocross/ track and aren't running more that stg 2 and are just fine with the factory pcv. When it dies, replace with BL.
 
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AceHammer

Ready to race!
Location
NY USA
Car(s)
2015 A3
Yea I ran a BMS catch can for a while and would get a noticeable amount of oil in it on the track, but that was also the original PCV from 2015. Even with that, I would blow smoke during hard braking, from it going into air mode.

I considered the BL but figured that high boost would just break it again, and I'd rather have all the blowby be filtered rather than have any go-in unfiltered while just driving around normally.

I really wish someone would come out with a true A/O separator kit, it would require a metal pan though and I think this is why companies don't want to make one as the cost would be too high for people. I believe the lms car has a return on the can to the pan, so they don't have to deal with losing oil.

Edit - 100% agree for the average user here a BL valve by itself is adequate. Adding in an inline can just helps out a bit more for track use on aggressive tires. It's that top 5% that go hard with big power or super sticky tires, that would see a benefit to using a full replacement.

Edit 2 - Also for anyone that's thinking a full replacement will solve the carbon build-up issue, it won't. IMO about 10% of the build-up during normal driving is from it venting in 'air mode'. The other 90% is from that stupid valve overlap they use to reduce NOX emissions instead of an egr valve.
 
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GTIfan99

Autocross Champion
Location
FL
Yea I ran a BMS catch can for a while and would get a noticeable amount of oil in it on the track, but that was also the original PCV from 2015. Even with that, I would blow smoke during hard braking, from it going into air mode.

I considered the BL but figured that high boost would just break it again, and I'd rather have all the blowby be filtered rather than have any go-in unfiltered while just driving around normally.

I really wish someone would come out with a true A/O separator kit, it would require a metal pan though and I think this is why companies don't want to make one as the cost would be too high for people. I believe the lms car has a return on the can to the pan, so they don't have to deal with losing oil.

Edit - 100% agree for the average user here a BL valve by itself is adequate. Adding in an inline can just helps out a bit more for track use on aggressive tires. It's that top 5% that go hard with big power or super sticky tires, that would see a benefit to using a full replacement.
I'm also looking at a baffled oil pan.
 

AceHammer

Ready to race!
Location
NY USA
Car(s)
2015 A3
I'm also looking at a baffled oil pan.
Was thinking about a baffled pan. Not sure if it would help control the oil in the head, but an extra 1 quart of oil never hurts. The track cars do run the same plastic oil pan however so I figured it's adequate for now.

edit - 06K103600D is the part number for the oil pan off the RS3 LMS car
 

GTIfan99

Autocross Champion
Location
FL
Was thinking about a baffled pan. Not sure if it would help control the oil in the head, but an extra 1 quart of oil never hurts. The track cars do run the same plastic oil pan however so I figured it's adequate for now.

edit - 06K103600D is the part number for the oil pan off the RS3 LMS car
Is the RS3 LMS oil pan baffled?
 

AceHammer

Ready to race!
Location
NY USA
Car(s)
2015 A3
Is the RS3 LMS oil pan baffled?
No it is the exact same pan the regular A3/Gti has.



From the parts diagram, they appear to run a line from their Air/Oil separator into where the drain plug goes on our cars.
Looked a bit closer to line from their A/O runs into the back of the block, the pan is still the same

Shouldn't have second-guessed myself. Found a better diagram, the A/O runs into a custom drainplug, that is open


Edit - Photo
b15b207104733db22d5bc1009dff6c48.png
 

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GTIfan99

Autocross Champion
Location
FL
No it is the exact same pan the regular A3/Gti has.



From the parts diagram, they appear to run a line from their Air/Oil separator into where the drain plug goes on our cars.
Looked a bit closer to line from their A/O runs into the back of the block, the pan is still the same

Shouldn't have second-guessed myself. Found a better diagram, the A/O runs into a custom drainplug, that is open


Edit - Photo
View attachment 205526
I wonder if vw would sell the AOS?
 
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