GOLFMK8
GOLFMK7
GOLFMK6
GOLFMKV

Smoke Factory at the track.

DAS_STIG

Banned
Location
Chicago
So what is the underlying cause of this?failed pcv? Since plenty of people track without catch cans wondering why some have this issue.
 

aaronc7

Autocross Champion
Location
USA
Car(s)
17 S3
If that was what was happening, then your catch can solution on track would have solved the issue and caught a bunch of oil, no?

So the oil that is burning in the engine, causing the huge smoke cloud was not entering the intact tract via the TIP hose/vent.

With the stock pcv plate/oil separator/whatever, there is also a way for air/oil vapor/liquid oil to get into the intake tract and that is directly into the intake manifold near the valves.

With the aftermarket pcv plate solutions, that intake manifold path is completely blocked off and is likely the real fix for track use. The catch can is just an extra on top that is nice.

That's my line of thinking anyways.
 

aaronc7

Autocross Champion
Location
USA
Car(s)
17 S3
This shows the flow of crankcase pressure, starting at the red highlighted section, and then the dotted white line splits inside the pcv plate. One path is to the TIP and the other is to the intake manifold/intake valves. In boost the flow path is the TIP and in vacuum the flow path is to the intake manifold.



This diagram shows the air flow path/direction under boost, this is basically how an aftermarket PCV plate functions 100% of the time.



This diagram shows the air flow path/direction in vacuum, note that air is actually pulled FROM the TIP, down past the PCV valve into the head/crankcase in this scenario, and that fresh clean air then circulates thru the engine.

If I had to make a guess it's a combination of the oil pooling at the front of the head under heavy braking....filling up the pcv plate area, and then the high vacuum in the intake manifold sucking the oil up. Then after the braking zone you're back on the gas and you have the smoke show. Also the intake manifold vent is front passenger side of the pcv plate too...which probably makes heavy braking followed by left turn the worst case scenario.

 
Last edited:

donefor

Go Kart Newbie
Location
usa
If that was what was happening, then your catch can solution on track would have solved the issue and caught a bunch of oil, no?

So the oil that is burning in the engine, causing the huge smoke cloud was not entering the intact tract via the TIP hose/vent.

With the stock pcv plate/oil separator/whatever, there is also a way for air/oil vapor/liquid oil to get into the intake tract and that is directly into the intake manifold near the valves.

With the aftermarket pcv plate solutions, that intake manifold path is completely blocked off and is likely the real fix for track use. The catch can is just an extra on top that is nice.

That's my line of thinking anyways.

Yes, that might explain the second mechanism of the smoking that i didn't understand today , even though i mentioned the modes of PCV operation a few days ago, that part of my brain may have been out to lunch :D

The coke bottle trick did work for a few laps at full pace, but in the next session it did not and i was black flagged, so i dunno... i'd like to forget i wasted that time :mad:

Excellent point, though, the aftermarket plates must block off that port to the intake runners and maybe there's no plausible way for all that smoke to be generated from residual oil in the pipes, and that would also explain why only some plates are said to work on track.
 

aaronc7

Autocross Champion
Location
USA
Car(s)
17 S3
I did a track day and lasted about 3 laps until my catch can filled with oil and then spilled out on my headers. Huge smoke cloud, I'm just lucky the car didn't catch on fire. But I feel ya, it's really frustrating.

That was a different car, but the problem was similar in a lot of ways. Oil pooling in the head, high vacuum from intake manifold literally sucking it up (into the can in my case). So I think that may be what's going on here.

If there was a way to block off the vacuum source on the stock pcv plate, that would be pretty neat I think. Utilize the stock "oil separator" in the valve and have all venting go out to the TIP. Probably more hassle than it's worth though I imagine.
 

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
I did a track day and lasted about 3 laps until my catch can filled with oil and then spilled out on my headers. Huge smoke cloud, I'm just lucky the car didn't catch on fire. But I feel ya, it's really frustrating.

That was a different car, but the problem was similar in a lot of ways. Oil pooling in the head, high vacuum from intake manifold literally sucking it up (into the can in my case). So I think that may be what's going on here.

If there was a way to block off the vacuum source on the stock pcv plate, that would be pretty neat I think. Utilize the stock "oil separator" in the valve and have all venting go out to the TIP. Probably more hassle than it's worth though I imagine.

Whose OCC system do you have?
 

aaronc7

Autocross Champion
Location
USA
Car(s)
17 S3
Different car, that was on my C5Z at the track. I don't even have a Golf yet, I'm just a lurker who is bored and wanted to jump in on some tech discussions, lol. Been looking at Golf Rs though.

I have a Focus ST right now and there's been a lot of discussion and results showing that OCC has little to no effect on carbon buildup on the valves, so I don't run an OCC on it.

On a Golf I probably won't run on either unless I get into some autocross or track stuff and come across the issue. But I think "fixing" the pcv plate is probably the most important thing to do here for track stuff.. an OCC on the line is just a nice extra touch. It seems to be more of an oil control problem than a blowby problem-- seems like any of the full systems that include the pcv plate would work well for track applications.
 

DAS_STIG

Banned
Location
Chicago
Different car, that was on my C5Z at the track. I don't even have a Golf yet, I'm just a lurker who is bored and wanted to jump in on some tech discussions, lol. Been looking at Golf Rs though.

I have a Focus ST right now and there's been a lot of discussion and results showing that OCC has little to no effect on carbon buildup on the valves, so I don't run an OCC on it.

On a Golf I probably won't run on either unless I get into some autocross or track stuff and come across the issue. But I think "fixing" the pcv plate is probably the most important thing to do here for track stuff.. an OCC on the line is just a nice extra touch. It seems to be more of an oil control problem than a blowby problem-- seems like any of the full systems that include the pcv plate would work well for track applications.

The VW community has been proving the minimal to no impact of catch cans on carbon buildup since 2005.
 

aaronc7

Autocross Champion
Location
USA
Car(s)
17 S3
When I had a Mazdaspeed 3, the biggest contributor to carbon buildup on the valves and just crap in the intake manifold was the EGR system.

Now cars don't have EGR systems and they get the same results (reduce NOx emissions at least?) apparently by tweaking valve timing during various operating conditions... I haven't spent a whole lot of time digging into this, but I think those conditions force the intake valve to be exposed to combustion byproducts and gunk up the valves in a similar fashion.

At the end of the day I don't worry about it too much anymore.

Sorry don't mean to derail this too much.
 

donefor

Go Kart Newbie
Location
usa
No derail at all man, thanks for posting those pictures and setting me straight after my sleepwalk post haha. Not happy that i had this happen at the expense of a track day, but hopefully folks will see this before doing what i did.
 

FRDRICE

New member
Location
GA
Following this thread.
 

Quebster

Autocross Newbie
Location
Dallas, Tx
This diagram shows the air flow path/direction in vacuum, note that air is actually pulled FROM the TIP, down past the PCV valve into the head/crankcase in this scenario, and that fresh clean air then circulates thru the engine.
This diagram shows the air flow path/direction in vacuum, note that air is actually pulled FROM the TIP, down past the PCV valve into the head/crankcase in this scenario, and that fresh clean air then circulates thru the engine.

This last bit doesn’t make any sense. There is a check valve in the OEM PCV that prevents air going from TIP to PCV. The purpose of the connection to the TIP is to both provide vacuum to the crankcase and vent crankcase pressure from blowby.

Speaking of which, OP, your method of adding a “catch bottle” was preventing the PCV from doing its job of venting crankcase pressure I would think... this could explain the smoke later on using that method.

If the PCV doesn’t vent, oil will get past your turbo seals, your upper timing cover, basically it will start coming out everywhere it shouldn’t and this will cause smoke. This happened with my VWR plate once it busted.
 

aaronc7

Autocross Champion
Location
USA
Car(s)
17 S3
This last bit doesn’t make any sense. There is a check valve in the OEM PCV that prevents air going from TIP to PCV. The purpose of the connection to the TIP is to both provide vacuum to the crankcase and vent crankcase pressure from blowby.

Speaking of which, OP, your method of adding a “catch bottle” was preventing the PCV from doing its job of venting crankcase pressure I would think... this could explain the smoke later on using that method.

If the PCV doesn’t vent, oil will get past your turbo seals, your upper timing cover, basically it will start coming out everywhere it shouldn’t and this will cause smoke. This happened with my VWR plate once it busted.

I don't know what you mean by "air going from TIP to PCV". As you can see in the diagram you quoted, fresh filtered air flows from the TIP, past what is labeled "pcv valve" in the diagram. Now this air is located in the valve cover and circulates thru the entire crankcase. This circulated air picks up a lot of blowby, fuel vapor, water vapor whatever else along the way and enters the pcv again in the top left port in the diagram...thru the pcv and then finally into the intake manifold where it's sucked thru and burned in the cylinders.

At wide open throttle, boost pressure in the intake manifold closes check valve 1. Elevated crankcase pressure from blowby opens check valve 2 and it takes the path of least resistance out via the TIP. The TIP should create a slight suction force with high velocity air streaming past it... but from what I've seen it's relatively small amount of vacuum and not hugely significant, but hey I'll take any assist that I can.

At the end of the day it functions like every other single modern pcv system I've seen, but the design is a bit different. I had to stare at those diagrams for a while for everything to make sense. I guess standard german fashion.. let's just make this thing overly complicated lol.

The aftermarket systems remove the functionality depicted in the diagram you posted. In which case you are exactly right-- all pcv flow is out the TIP and is the only (minor) source of vacuum in the system.
 

Quebster

Autocross Newbie
Location
Dallas, Tx
I don't know what you mean by "air going from TIP to PCV". As you can see in the diagram you quoted, fresh filtered air flows from the TIP, past what is labeled "pcv valve" in the diagram. Now this air is located in the valve cover and circulates thru the entire crankcase. This circulated air picks up a lot of blowby, fuel vapor, water vapor whatever else along the way and enters the pcv again in the top left port in the diagram...thru the pcv and then finally into the intake manifold where it's sucked thru and burned in the cylinders.

At wide open throttle, boost pressure in the intake manifold closes check valve 1. Elevated crankcase pressure from blowby opens check valve 2 and it takes the path of least resistance out via the TIP. The TIP should create a slight suction force with high velocity air streaming past it... but from what I've seen it's relatively small amount of vacuum and not hugely significant, but hey I'll take any assist that I can.

At the end of the day it functions like every other single modern pcv system I've seen, but the design is a bit different. I had to stare at those diagrams for a while for everything to make sense. I guess standard german fashion.. let's just make this thing overly complicated lol.

The aftermarket systems remove the functionality depicted in the diagram you posted. In which case you are exactly right-- all pcv flow is out the TIP and is the only (minor) source of vacuum in the system.

I guess it just goes against everything I've been told about the OEM PCV system thus far. That there is a check valve in the PCV to where air can only move out of the PVC into the turbo inlet, and not the other way around. I've also been told that if you blow into that hose from the turbo inlet to the PCV, and you can move air, that the PCV is busted. So that's all false?

I understand the diagram has an arrow moving into in the PCV from the turbo inlet, and that's what doesn't make sense to me. But the diagram also shows the connection to the turbo inlet going the wrong way so, I was wondering how accurate it all was I guess?

I guess I've just been misinformed this whole time, because I've never seen as much info on the PCV as I have here and with these diagrams. Where can I see them in full? PCV is the biggest issue on BT builds and track-built cars that I'm aware of. My Spulen V2 just displaced several liters of oil into my turbo (destroying it) over a track day, so I'm trying to figure out wtf is going on.
 
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