Understanding the MK7 PCV function, retrofitting the MK8 PCV, and why catch cans are bullshit(IMO)

[DerHase]

I do track the car (with you before) but I don't experience smoking or or excessive oil consumption.

Edit* - Brocoli

Ahh that's right. (Had to zoom in on the profile pic). We met at Fastivus 2022 originally where me and my dad were parked next to you (and it was your first track day IIRC?).


I wouldn't worry about anything until it becomes a problem.

@tigeo has tracked his IS38 wagon on the MK7 BL valve with a Unitronic intake/TIP without problems for a while.

The main take away is IF you experience issues, people now might have a clue and some other options rather than throw a $600-700 plate on the car which adds its own problems.

I'd just bring an OEM TIP with you to the track in the meantime, could be a potentially easy thing to change out and make the situation better.


If you watch the on track video, basically red on the CC gauge = bad or less than ideal.

What goes on crankcase wise depends a lot on the specific corner and driver inputs/habits. Long periods of holding steady throttle are in general the worst.

I'll be trying to do some similar testing at autocross this year with stock vs aftermarket turbo inlet pipes. I intended to run the stock one in basic retrofit form but it was a busy weekend with instructing, fixing a friend's broken Corvette, etc and laziness ultimately won out

 

[DerHase]

So as far as PCV vacuum source goes... a genuine $175 APR is pretty damn similar to the $46 Epman...

If you missed it, I took a few measurements of them side by side here:
https://www.youtube.com/shorts/axiZiMiHjpw

Thanks to @scrllock for sending it my way.


Will update the website with the APR full retrofit data when I get a chance to test it again. Had a weird bump in the middle of the pull which I think threw things off.

Keep in mind absolute values are less of an issue rather than general ideas of what's going on.

APR was tested on a different set of wheels/tires FWIW. Not that I think the car is drastically changed, but might minorly affect things.

As I said before this is really a job for a flow bench to eliminate other variables.

 

[tigeo]

So as far as PCV vacuum source goes... a genuine $175 APR is pretty damn similar to the $46 Epman...

View attachment 299911

If you missed it, I took a few measurements of them side by side here:
https://www.youtube.com/shorts/axiZiMiHjpw

View attachment 299912


Thanks to @scrllock for sending it my way.


Will update the website with the APR full retrofit data when I get a chance to test it again. Had a weird bump in the middle of the pull which I think threw things off.

Keep in mind absolute values are less of an issue rather than general ideas of what's going on.

APR was tested on a different set of wheels/tires FWIW. Not that I think the car is drastically changed, but might minorly affect things.

As I said before this is really a job for a flow bench to eliminate other variables.

But bro...flow benches aren't reAL WorLd...bro...

 

[PerceivedShift]

So as far as PCV vacuum source goes... a genuine $175 APR is pretty damn similar to the $46 Epman...

View attachment 299911
=

The Epman interior looks far superior over APR

 

[GTIfan99]

Bro, that lip is to create a swirl effect. Everyone knows turbos love swirls. Duh. What's wrong with you guys?

 

[avenali312]

I threw the stock TIP and hose back on. Here are some photos of the MST that came off.

 

[DerHase]

I threw the stock TIP and hose back on. Here are some photos of the MST that came off.

Yeah I'd expect that to work more like the BMS than any of the others.

Temps/IATs aren't comparable on the full retrofit run, but you can get a general idea of the APR TIP. It's not terribly unlike the Epman. I suspect the temps can have an effect on the Venturi run. And of course they'll affect the WGDC as well.

Main takeaway is it's a bit worse than OEM in basic retrofit form, and still provides a bit more vacuum than "ideal" when combined with the Venturi. I wouldn't expect any issues from running it in full retrofit form though. Been doing it with the OEM one for a while.

 

[DerHase]

I think it's completely unnecessary and I'm not happy with how "stressed" the $$ Tiguan hose is with this setup... But testing this because people love their GD catch cans.

 

[dood.]

I think it's completely unnecessary and I'm not happy with how "stressed" the $$ Tiguan hose is with this setup... But testing this because people love their GD catch cans.

I mean how can you argue with this? From the BMS website:

“It's no secret that the Mk7 turbo motors can suffer from oil control problems causing oil to blow through and coat the intercooler and charge piping, gunking up intake valves and the VANOS system, lowering the effective octane, and generally degrading engine performance. The higher your boost levels the more apparent these problems become.

The solution to this problem has finally arrived. The BMS oil catch can.”

…full disclosure I have a BMS can on my car

 

[tigeo]

Done. Logging look normal vs. the standard retrofit/before venturi. All hail Plankton...er...Derhase!

Standard retrofit log:
https://datazap.me/u/karstgeo72/simos-tools-log-12292023?log=0&data=5-11

Full retrofit/venturi log:
https://datazap.me/u/karstgeo72/simos-tools-log-02282024?log=0&data=5-11

 

[Klrider44]

So I will have the parts to do the full retrofit next week. I will be utilizing the EQT charge pipe for the Venturi as a couple others have done. Does it matter at all where exactly on the charge pipe I tap it for the Venturi source?

 

[DerHase]

So I will have the parts to do the full retrofit next week. I will be utilizing the EQT charge pipe for the Venturi as a couple others have done. Does it matter at all where exactly on the charge pipe I tap it for the Venturi source?

Nah. Literally anywhere between turbo outlet and throttle body will work. I'd err on the side of caution and use a 1/8npt to 1/4 barb fitting to 1/4in hose then a 1/4 barb to 5/16 or 3/8 barb adapter for the original Tiguan hose.

There's no real downside to restricting the boost line a tiny bit.

 

[DerHase]

So I decided to add a central "MK8 PCV Repository" or whatever to the website. Shit is scattered around so much... I figured this would be easiest to keep one updated parts list with information, along with links to the videos/site pages where relevant info can be found:

https://www.datadrivenmqb.com/mk8pcv

If you haven't seen it on Facebook (or this forum post), it looks like @Alex@Stratified had some pretty killer results with the MK8 PCV on a customer's PMax 2260S car.

https://golfmk7.com/forums/index.ph...ning-info-and-help-thread.442129/post-8042541

To be 100% clear I don't think noticeable gains should be expected, though it may be possible if you have a far less than ideal setup. Or perhaps big ass turbos just create so much blow-by (and combined with certain TIP/intake combos) they really have a lot more to gain?

I'm not 100% sure just yet, but I will remain skeptical until some more people do some dyno tuning - preferably under some more controlled conditions (like running in basic + full retrofit form while still on the dyno).

 

[GTIfan99]

I took the @mrmatto method of upgrading to the mk8 PCV.

 

[PerceivedShift]

So I will have the parts to do the full retrofit next week. I will be utilizing the EQT charge pipe for the Venturi as a couple others have done. Does it matter at all where exactly on the charge pipe I tap it for the Venturi source?

Honestly I'd go with the ECS turbo muffler delete route and not bust into the EQT charge pipe. After doing mine that way I'm having second thoughts and might replace my EQT charge pipe I ruined and install the tap into the turbo muffler delete.