Klrider44
Go Kart Champion
- Location
- Bucks county PA
No real knock to speak of, I will be getting some logs. When I do I’ll send them over
7
Understanding the MK7 PCV function, retrofitting the MK8 PCV, and why catch cans are bullshit(IMO)
- Thread starter DerHase
- Start date
Thanks for the insightful feedback
When I get some more cash I'll probably try a full retrofit on my 2017 DSG R.
fretburnr
Ready to race!
- Location
- Chicago, IL
- Car(s)
- 2017 GTI Sport
Just another note: I checked the oil level today, and there has been zero measurable drop in level since my oil change last week despite the abuse.
Ready for action. Planning to A/B test later this weekend: PCV with/without cutout and with/without BMS CC. Have to find a good corner + straight. Also threw on the BMS TIP for good measure.
Can make the cut without too much drama with a heat gun + box cutter fwiw.
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DerHase
Autocross Champion
- Location
- Hampton Roads, VA
- Car(s)
- 2019 GTI Rabbit
I've taken an unexpected turn after finding some interesting articles and links to videos on arborist forums.
On 2 stroke chain saws it's insanely common for their crankcases to hold pressure and not leak oil, but they can suck air in past the crankcase seals. Because 2-strokes have a mixture of fuel and oil that is sucked in BELOW the piston, the effects of an air leak are particularly bad because it gets pulled in leaning out the A/F mixture which leads to burning up the piston and sleeve prematurely.
Here's a video showing how it's done in that application:
Now to develop a standardized test procedure...
On 2 stroke chain saws it's insanely common for their crankcases to hold pressure and not leak oil, but they can suck air in past the crankcase seals. Because 2-strokes have a mixture of fuel and oil that is sucked in BELOW the piston, the effects of an air leak are particularly bad because it gets pulled in leaning out the A/F mixture which leads to burning up the piston and sleeve prematurely.
Here's a video showing how it's done in that application:
Now to develop a standardized test procedure...
DerHase
Autocross Champion
- Location
- Hampton Roads, VA
- Car(s)
- 2019 GTI Rabbit
As for Partslink24 being accurate, I would say it's the same accuracy like OE ETKA, because both (Partslink24 and ETKA) are made by the same company, LexCom.
Difference is, ETKA is not available for unauthorized shops/workshops, Partslink24 is LexCom product for aftermarket. I have opportunity to work on both and ETKA is much better with far more search options. In ETKA you can search with part number, to check on what cars and model years was available, for example. Or when you have electric/electronic part, you can check what part no. have connectors connected to this part, and what pins are used in this particular connector. And ETKA has description of all PR numbers, not only the ones used in that particular car
2017 Sportwagen with a full retrofit on the way! Spent so much time reading through this whole thread and what a joy it’s been. Been ingesting oil. Not going out to events at all, just enjoy shaking up the groceries on the way home.
Klrider44
Go Kart Champion
- Location
- Bucks county PA
So I think my issue actually was traction control. I put a new digital dash in and the display messages are different than normal. I don’t think I had traction control completely off and the COBB traction was kicking in. Car feels good and I actually sent a log over to EQT and they cleaned up the fueling a touch from when I installed my blaze intake. Hopefully all is good and I will try to put the car through its paces with the new cutout PCV.
DerHase
Autocross Champion
- Location
- Hampton Roads, VA
- Car(s)
- 2019 GTI Rabbit
Well - the hole in the valve was not the hoped success on track yesterday. While the car never billowed massive clouds of smoke, there was a light trail of smoke from the tailpipes pretty often per @tigeo . Still waiting to see some video from him behind me.
I'm still going through ALL the stuff, but here's a quick overview:
I did have a GoPro facing rearwards for all but the first session I believe. Caught a couple minor puffs of smoke, but never got to the point of a CEL or major power loss. Again, interested to see video from behind me.
What's interesting is (it appears, from the below data) issues never happened until a bit into the session with oil temps elevated.
I went through just shy of 0.5qt of oil the entire day (which admittedly was not like a "normal" full track day - I did 18 full laps total, so not counting in/out lap), and majority of it was in session 2... where I did not empty the catch can after session 1. Sort of forgot/have not needed to do that in the past so was a bit lazy about that.
Also to my surprise the crankcase pressure spiked positive still with the hole in the valve:
And every session the Venturi hoses looked like this... I'm wondering if the Venturi fitting itself is failed with an external oil leak. Despite it looking like it's coming from the hose, I believe it's actually coming from that seam to the left of the writing on the Venturi.
Every time the crankcase pressure spiked, the PCV vacuum was lower than typically expected. I have a feeling that the catch can was full enough that oil sloshed inside it and was effectively blocking the Venturi from working. It was about half full after every session. You can see here that the positive pressure events only happened at elevated oil temps and when PCV vacuum was not sufficient.
And you can see the more egregious amounts of KR are basically isolated to 245F+ oil temps.
Some stuff that will factor in to all the above:
- The car now has an IS38. And the tune while a bit more mild on boost is far closer to most off the shelf tunes. ~26psi at 4500rpm, 22psi at 6000rpm.
- My car is a 2019. Previously had no major issues with the valve like this - though this was also before the IS38.
- Summit on the Shenandoah Circuit is a TON of turns. It's about as technical a track as it gets. Probably a much better torture test of the PCV system than VIR.
All in all I think I'm approaching the end of my abilities to test the limits of this setup and ideas to make it work. The last step is to get some actual engineers involved and discuss some of the above stuff that might factor in, plus the obvious parts differences went over earlier. I have (nearly) all the parts to install an oil cooler, so seeing if keeping oil temps down to lessen oil evaporation might be a future thing to mess with.
I have a phone call scheduled with the guys at Professional Awesome (who have experience as powertrain engineers) to try and get a bit more info on this entire situation.
In the meantime it's safe to say we've learned a bunch in general, and I think the MK8 PCV is a good street car solution. The hole in the valve seems to be a maybe-fix for street driven and potentially autocrossed cars. One guy had luck on track with it as well... but there's just too many damn variables.
I'll probably run both the modified and non-modified valves at VIR in December, if for no other reason than to somewhat assess the likelihood of problems brought on by IS20 vs IS38 power since I have previous data from the unmodified valve there to compare to.
I'm still going through ALL the stuff, but here's a quick overview:
I did have a GoPro facing rearwards for all but the first session I believe. Caught a couple minor puffs of smoke, but never got to the point of a CEL or major power loss. Again, interested to see video from behind me.
What's interesting is (it appears, from the below data) issues never happened until a bit into the session with oil temps elevated.
I went through just shy of 0.5qt of oil the entire day (which admittedly was not like a "normal" full track day - I did 18 full laps total, so not counting in/out lap), and majority of it was in session 2... where I did not empty the catch can after session 1. Sort of forgot/have not needed to do that in the past so was a bit lazy about that.
Also to my surprise the crankcase pressure spiked positive still with the hole in the valve:
And every session the Venturi hoses looked like this... I'm wondering if the Venturi fitting itself is failed with an external oil leak. Despite it looking like it's coming from the hose, I believe it's actually coming from that seam to the left of the writing on the Venturi.
Every time the crankcase pressure spiked, the PCV vacuum was lower than typically expected. I have a feeling that the catch can was full enough that oil sloshed inside it and was effectively blocking the Venturi from working. It was about half full after every session. You can see here that the positive pressure events only happened at elevated oil temps and when PCV vacuum was not sufficient.
And you can see the more egregious amounts of KR are basically isolated to 245F+ oil temps.
Some stuff that will factor in to all the above:
- The car now has an IS38. And the tune while a bit more mild on boost is far closer to most off the shelf tunes. ~26psi at 4500rpm, 22psi at 6000rpm.
- My car is a 2019. Previously had no major issues with the valve like this - though this was also before the IS38.
- Summit on the Shenandoah Circuit is a TON of turns. It's about as technical a track as it gets. Probably a much better torture test of the PCV system than VIR.
All in all I think I'm approaching the end of my abilities to test the limits of this setup and ideas to make it work. The last step is to get some actual engineers involved and discuss some of the above stuff that might factor in, plus the obvious parts differences went over earlier. I have (nearly) all the parts to install an oil cooler, so seeing if keeping oil temps down to lessen oil evaporation might be a future thing to mess with.
I have a phone call scheduled with the guys at Professional Awesome (who have experience as powertrain engineers) to try and get a bit more info on this entire situation.
In the meantime it's safe to say we've learned a bunch in general, and I think the MK8 PCV is a good street car solution. The hole in the valve seems to be a maybe-fix for street driven and potentially autocrossed cars. One guy had luck on track with it as well... but there's just too many damn variables.
I'll probably run both the modified and non-modified valves at VIR in December, if for no other reason than to somewhat assess the likelihood of problems brought on by IS20 vs IS38 power since I have previous data from the unmodified valve there to compare to.
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summerflame
New member
- Location
- malaysia
- Car(s)
- Golf 6 GTI
Just to let you know on the oil cooling, most those aftermarket external oil cooler with size of 10+ rows is not sufficient for track use, look at m4 oil cooler size for a starting point. Mine has a 20+ rows one, less than half the width of m4 cooler radiator, and the oil temps still goes quite high.
Also, looks to me the sandwich style adapter that goes to to oil filter, might not be very efficient, look at the internal structure looks like not 100% of the oil is going into the oil cooler radiator, some will get bypassed and go into oil filter directly, my mk6 is currently same as that one. The adapter that replaces the factory oil cooler might be alot better.
DerHase
Autocross Champion
- Location
- Hampton Roads, VA
- Car(s)
- 2019 GTI Rabbit
Yeah I've already done quite a bit as far as data collection goes for that:
https://www.datadrivenmqb.com/drivetrain/oil-cooler-duct-conclusionresults
https://www.datadrivenmqb.com/drivetrain/coolingdata
https://www.golfmk7.com/forums/inde...tech-read-before-adding-an-oil-cooler.426885/
A 19 row cooler isn't technically "enough" on paper, but in reality it buys enough time and slows down heat build up to the point that a typical 20-25 min session is no issue. Realistically a 34 row cooler is needed for something in the 350hp range, or twin 16/19 row oil coolers (in parallel).
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summerflame
New member
- Location
- malaysia
- Car(s)
- Golf 6 GTI
Haven't seen those posts of yours before, that's another super great findings! Thank you so much
DerHase
Autocross Champion
- Location
- Hampton Roads, VA
- Car(s)
- 2019 GTI Rabbit
Bunch of relevant PCV related stuff in the last two trip reports:
https://www.datadrivenmqb.com/tripreports/fastivus2024
https://www.datadrivenmqb.com/tripreports/2024tsccax7
It's really looking like for the later cars, it's looking like the MK8 full retrofit should be a pretty good option for autocross, and probably fit the bill for tracks that aren't littered with multiple long sweeping RH turns over a relatively short lap.
I think 15-16 GTI in particular need to try either an AP or maybe BM valve and *maybe* with a BMS catch can, but if that's no good then straight to a PCV plate.
The Golf R stuff has been much more of a mixed bag.
One interesting thing about the 15-16 vs 17-18 CXCA/CXCB pistons was sort of found here... which definitely could explain why there are such stark differences on the early cars. I suspect it extends to the early CXBA and CXBB 1.8s as well. Basically everything with the 06H 198 151 F piston rings stock looks like it it has a low likelihood of success if asking it to do track or autocross.
https://www.golfmk7.com/forums/index.php?threads/piston-markings-decode.453080/
https://www.datadrivenmqb.com/tripreports/fastivus2024
https://www.datadrivenmqb.com/tripreports/2024tsccax7
It's really looking like for the later cars, it's looking like the MK8 full retrofit should be a pretty good option for autocross, and probably fit the bill for tracks that aren't littered with multiple long sweeping RH turns over a relatively short lap.
I think 15-16 GTI in particular need to try either an AP or maybe BM valve and *maybe* with a BMS catch can, but if that's no good then straight to a PCV plate.
The Golf R stuff has been much more of a mixed bag.
One interesting thing about the 15-16 vs 17-18 CXCA/CXCB pistons was sort of found here... which definitely could explain why there are such stark differences on the early cars. I suspect it extends to the early CXBA and CXBB 1.8s as well. Basically everything with the 06H 198 151 F piston rings stock looks like it it has a low likelihood of success if asking it to do track or autocross.
https://www.golfmk7.com/forums/index.php?threads/piston-markings-decode.453080/
MonkeyMD
Autocross Champion
Can confirm. 16 1.8 AP so far so good, but haven't done track yet with it (& probably not anyone soon)