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

[nomunic]

"Ventilate the valve from the get go" as in do the full retrofit only and don't bother with the basic, yeah?

I think he means cutting out the section of the valve, as shown in previous updates

 

[Ambitorus]

I think he means cutting out the section of the valve, as shown in previous updates

The modification to the Mk8 valve as shown here? Maybe I missed an update but I thought it was still under investigation.

 

[fretburnr]

TECHNICALLY the MK8 full retrofit is not "legal" for SCCA street class. Call a dealer (NOT some online parts look up!) and verify by VIN which is the latest revision.

It is PROBABLY:
AP for all 15-18 GTI and all 15-21 1.8L
BM for all 15-18 Golf R
BK for all 19+ GTI
BL for 19 Golf R

If you keep the stock TIP, the stock system while not "great" should work. I SUSPECT on the BK AND BL ONLY valves you could ventilate those MK7 valves to the cam cover to help keep oil from being pulled up the block passage like I've been doing on the MK8 valve. If you ever replace the TIP, then this setup will still not be doing you any favors for crankcase pressure, but it should still be more resistant to pushing oil up the passage. This modification should NOT be done to the AP/BM valves because they already only breathe on the cam cover. I THINK the problem with those valves is they have no way to drain any oil mist that DOES make it inside, and so they build up crap inside over time.

That said, I don't think anybody will give you shit for running a MK8 basic retrofit. This is what the SCCA solo national champ used last year for STH where it's also technically not legal (though catch cans are as long as the stock PCV isn't replaced.

SCCA rules are dumb and I will die on that hill

Agreed! SCCA rules are super annoying. These type of changes offer zero performance benefit, but a massive reduction in headaches.

I'm ok with "breaking" the SCCA rules to go with the full retrofit, since this is keeping me from doing more track days. Do I just need some 5/16" vacuum hose to plumb the TMD to the venturi?

 

[tmw2442]

Agreed! SCCA rules are super annoying. These type of changes offer zero performance benefit, but a massive reduction in headaches.

I'm ok with "breaking" the SCCA rules to go with the full retrofit, since this is keeping me from doing more track days. Do I just need some 5/16" vacuum hose to plumb the TMD to the venturi?

The chances of any rule nerd launching a protest is near zero (especially at a local event....) and if they are the type to know a mk7-8 pcv valve from another (be another mqb nerd....), and what revision should be specifically on their/your car, they probably need the pcv mod themselves and would most likely, shut there mouth and do some part to all of the retrofit. IMO.

Local SCCA/HPDE events, etc... are supposed to be 9/10th fun, learning/meeting with your fellow car people, and helping each other out, it was keeps the sport/hobby alive. IMO...not 7/10th nerds arguing/protesting pcv valve revision part numbers.

Hopefully most, leave the "I'm launching a protest....
1. your pcv valve gave you a .01 of a second
2. caused me to hit a cone
3. miss my 12 sided dice roll
4. overheated my tires
5. boiled my 5 year old brake fluid
6. left oil on the track
7. and caused all my face-ta-tube-gram followers to unsub....

...I request a reeeeeee run, an invest-i-gation, and a man'amp-pon for my bleeding.... " ; for a PCV valve; to the "I'm definitively going to make nationals..."... one....day.... , aspiration nerds;

who haven't yet broken into the top 1/3 of pax at a local event or made it out of C group on track day. NERDs....

ALL hopedfully, want to ingest an minimal amount of oil, keeping our cars as healthy as possible, while; we convert dead dinosaurs into noise, speed, and a slight amount of adrenaline/FUN!

 

[DerHase]

"Ventilate the valve from the get go" as in do the full retrofit only and don't bother with the basic, yeah?

Not what I meant... but also yes. IMO the basic retrofit is ONLY worth doing if you are wanting to

1. See if you can get by as cheaply as possible
2. Still have an OEM TIP
3. Are fully willing to buy the parts to do the full retrofit

Otherwise IMO there's no benefit to it.

I think he means cutting out the section of the valve, as shown in previous updates

Correct, this was what I was alluding to.

The modification to the Mk8 valve as shown here? Maybe I missed an update but I thought it was still under investigation.

Haven't released a video (working on it now - I have another valve to cut up and demonstrate on), but so far it's sorted out 3 cars. 1 on track, 1 autocross, and 1 on the street (doesn't see track time at all). There's one more that still smoked (though he did report far less than before) on track... but we haven't entirely ruled out some other mechanical issues just yet. Non-OEM rear main seal, engine has had a bunch of repairs, and has had problems with every PCV solution so far.

We put the valve on Jacob's GTI and he was able to do all 5 autocross runs last month with zero problems (which he was 0 for 2 in getting all his runs prior to that because of smoking issues).

Agreed! SCCA rules are super annoying. These type of changes offer zero performance benefit, but a massive reduction in headaches.

I'm ok with "breaking" the SCCA rules to go with the full retrofit, since this is keeping me from doing more track days. Do I just need some 5/16" vacuum hose to plumb the TMD to the venturi?

If you do the full retrofit, the info is covered here. If you're using the 034 TMD, then the Tiguan hose can be used as-is. Just need the fittings for the TMD which is covered here:
https://www.datadrivenmqb.com/mk8pcv

The chances of any rule nerd launching a protest is near zero (especially at a local event....) and if they are the type to know a mk7-8 pcv valve from another (be another mqb nerd....), and what revision should be specifically on their/your car, they probably need the pcv mod themselves and would most likely, shut there mouth and do some part to all of the retrofit. IMO.

Local SCCA/HPDE events, etc... are supposed to be 9/10th fun, learning/meeting with your fellow car people, and helping each other out, it was keeps the sport/hobby alive. IMO...not 7/10th nerds arguing/protesting pcv valve revision part numbers.

Hopefully most, leave the "I'm launching a protest....
1. your pcv valve gave you a .01 of a second
2. caused me to hit a cone
3. miss my 12 sided dice roll
4. overheated my tires
5. boiled my 5 year old brake fluid
6. left oil on the track
7. and caused all my face-ta-tube-gram followers to unsub....

...I request a reeeeeee run, an invest-i-gation, and a man'amp-pon for my bleeding.... " ; for a PCV valve; to the "I'm definitively going to make nationals..."... one....day.... , aspiration nerds;

who haven't yet broken into the top 1/3 of pax at a local event or made it out of C group on track day. NERDs....

ALL hopedfully, want to ingest an minimal amount of oil, keeping our cars as healthy as possible, while; we convert dead dinosaurs into noise, speed, and a slight amount of adrenaline/FUN!

Yeah this is basically how it generally is/should be.. but figured I'd just cover bases in case. It's technically not legal.

If I wanted a truly legal (well, 100% OEM visually correct) option then I'd run the BM revision PCV (15-18 Golf R) in GS. 100% protest-proof would be the AP valve for a 15-18 GTI.

 

[DerHase]

Set to post tomorrow morning:

There's a bit of audio weirdness in the intro - been playing with different mics and trying to see which work best and most inexpensive ones suck apparently. The intro is the worst of it, and I tried to voice-over as much as I could as my wired mic is way better.

 

[Klrider44]

Set to post tomorrow morning:

There's a bit of audio weirdness in the intro - been playing with different mics and trying to see which work best and most inexpensive ones suck apparently. The intro is the worst of it, and I tried to voice-over as much as I could as my wired mic is way better.

I will definitely be giving the cutout a try. I am a hybrid turbo 2015 GTI and I have been able to induce smoking on the street with the full retrofit. Now I also got the knockoff BMS catch can, but have yet to install it. Should I throw that on when I perform the cutout?

 

[JTM88]

I put my GTI back to stock, if anyone is interested in a full MK8 retrofit with the 034 TMD. I have it for sale.

https://www.golfmk7.com/forums/inde...sors-edit-prices-reduced.452054/#post-8078145

 

[fretburnr]

Got the full retrofit parts ordered up over the weekend, hopefully install next weekend, then I have an event on the 14th. We'll see if I can avoid making smoke with the changes!

 

[bbroecker37]

Set to post tomorrow morning:

There's a bit of audio weirdness in the intro - been playing with different mics and trying to see which work best and most inexpensive ones suck apparently. The intro is the worst of it, and I tried to voice-over as much as I could as my wired mic is way better.

I Installed the full retrofit this past weekend. I'm excited to see how it helps with oil consumption. I noticed when I was using the basic retrofit for a week. That my aftermarket turbo inlet was not producing enough vacuum and there was a lot of oil in the turbo inlet. A lot more compared to the stock "AH" PCV that came on my 2016 GTI. I bought the 034 TMD and connected the venturi. Things are running good. I'll check back in a week to see how much oil accumulated in the turbo inlet but I'm interested in modifying the PCV if there is still a lot of blowby.

 

[fretburnr]

Also wanted to add I finally finished going through all the videos (and subscribing). Excellent work, and what a great resource. Thanks @DerHase

Hopefully I'll have a good data point for you after my event on the 14th.

 

[DerHase]

I will definitely be giving the cutout a try. I am a hybrid turbo 2015 GTI and I have been able to induce smoking on the street with the full retrofit. Now I also got the knockoff BMS catch can, but have yet to install it. Should I throw that on when I perform the cutout?

Def let me know how it works out either way.

I honestly don't think the can is NEEDED, but it can more so be a good indicator if nothing else.

I Installed the full retrofit this past weekend. I'm excited to see how it helps with oil consumption. I noticed when I was using the basic retrofit for a week. That my aftermarket turbo inlet was not producing enough vacuum and there was a lot of oil in the turbo inlet. A lot more compared to the stock "AH" PCV that came on my 2016 GTI. I bought the 034 TMD and connected the venturi. Things are running good. I'll check back in a week to see how much oil accumulated in the turbo inlet but I'm interested in modifying the PCV if there is still a lot of blowby.

Nice! One thing to note is that on the 2015-16 cars, a LOT seems to be oil level related. I've had one guy who did the retrofit and all was good, then months later they did an oil change and it smokes. Check oil level when hot and sure enough it's slightly overfilled. Pulled a bit out and I haven't heard back from them since.

Anybody who checks their oil level when the car hasn't just been driven for 20+ min is probably actually slightly overfilling.

Also wanted to add I finally finished going through all the videos (and subscribing). Excellent work, and what a great resource. Thanks @DerHase

Hopefully I'll have a good data point for you after my event on the 14th.

Thanks!

PM me your VIN to add to the list. Also want to make sure your car wasn't built with some of the older 2016 MY parts. If so then it's probably advised to go ahead and just put the hole in your valve prior to the track day so you don't have to possibly futz around with it while there. I mean I suppose you could take a hot knife with you to the track, but that sounds like no fun to me.








And because I know someone will ask at some point:
- While the mod COULD be done to a BL or BK valve (or a MK8 basic retrofit), I don't think that it's a great idea. Without the Venturi the diaphragm is still wide open too often (and even worse if aftermarket TIP). You can still end up with a crankcase pressure issue, and this can still push aerated oil into the valve.
- Doing the modification to an AH/AP/BM etc style valve is pointless - it's already vented to the cam cover stock. Personally I think the BM valve is probably the "best" MK7 valve to run without a Venturi if I had to guess.

 

[ITGUY]

Has anyone ran and tested Radium Engineering Catch can ? I also see they have a bunch of V2 quick connects available.

 

[scrllock]

If the hose is long enough I don't see why you couldn't run it with the mk8 pcv and the 14-0668 V2 quick-connect on a Mk7 TIP connection.

 

[fretburnr]

Did the full retrofit today including 034 TMD (but without cutting a hole in the valve). It went fairly smoothly thanks to the thorough videos. Tbh this wasn't terribly difficult overall, I've certainly had worse jobs. The biggest bitch was a couple of those little pinch type hose clamps, between N80 and PCV, as well as at the venturi.

I flipped the worm clamp on the coupler as you did, but I left the spikes where they were, unfolded the tabs to slip out the clamp, and after flipping it I re-secured the spike tabs.

I did observe some slight wear on the intake cam lobes. It's not terrible, but it's a bit concerning as I've had negligible wear on previous cars of other makes with higher mileage.

Drove the car around the block just to make sure everything was hooked up right, but haven't run it hard or properly tested it yet.