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

[SYMAWD]

Got it. The real question is how much oil are you burning between sessions/over the day?

I was down a quart with about 30 minutes of track time. I can definitely try with a larger TIP. Should I just get the BMS one?

About 3 sessions like this, but the first one was a bit longer before I got the EPC light.

 

[DerHase]

I was down a quart with about 30 minutes of track time. I can definitely try with a larger TIP. Should I just get the BMS one?

About 3 sessions like this, but the first one was a bit longer before I got the EPC light.

Yeah if there's any track that'll fuck with these cars' PCV systems it looks like NJMP is the one.


The BMS is the "best" one I've tested with the Venturi so far FWIW. It's a safe bet to rule that out and is one of the cheaper options available.

Alternatively - restricting the Venturi boost line is an option.

 

[SYMAWD]

Yeah if there's any track that'll fuck with these cars' PCV systems it looks like NJMP is the one.


The BMS is the "best" one I've tested with the Venturi so far FWIW. It's a safe bet to rule that out and is one of the cheaper options available.

My next 3 days are on Thunderbolt and there's no long sustained rights there so hopefully things go better.

I might just need to go back to a stock map for Lightning.

 

[DerHase]

My next 3 days are on Thunderbolt and there's no long sustained rights there so hopefully things go better.

I might just need to go back to a stock map for Lightning.

Also forgot, this is one other option if you want to attempt to sort it out:

$130 catch can kit (looks exactly the same as BMS) from Ebay. You don't NEED to install it by hacking up the MK7 hose, but I wanted to make it fit better and make sure nothing rubbed or would pop off so this was my solution.

Hasn't been track tested yet but I see no reason it wouldn't work.

 

[GTIfan99]

Also forgot, this is one other option if you want to attempt to sort it out:

View attachment 300947

$130 catch can kit (looks exactly the same as BMS) from Ebay. You don't NEED to install it by hacking up the MK7 hose, but I wanted to make it fit better and make sure nothing rubbed or would pop off so this was my solution.

Hasn't been track tested yet but I see no reason it wouldn't work.

Link for the ebay cc. My BMS went with the old car. I guess I should have grabbed it before selling.

 

[DerHase]

Link for the ebay cc. My BMS went with the old car. I guess I should have grabbed it before selling.

So... funny thing about the MK8 system... on a MK8. You literally cannot do this because the "boost hose" + Venturi is all integrated within the red part of this diagram.

You could technically cut the big hose in half and run a can in between... but then you're pulling stupid vacuum on the can as well. The way it's set up for the MK7 retrofit, the can only ever sees whatever the TIP is generating vacuum-wise. Plus the little volume of boost from the Venturi.

Any chance you can see if it's possible to log the G950 sensor on your new GTI?

Ebay can though for reference... looks like they have an actual online store as well:
https://jackspaniaracing.shop/produ...volkswagen-mk7-golf-gti-2-0t-a3-tt-s3-8v-1-8t

For the record: The Tiguan hose does NOT seem to like to be twisted how it is. I question long term durability. It could eventually leak at some of the joints near the Venturi to hose connections, etc. Understand that if using for a retrofit, you might fuck up a $135 hose.

 

[GTIfan99]

I guess I'll just have to see if the mk8 has issues.

 

[scrllock]

So... funny thing about the MK8 system... on a MK8. You literally cannot do this because the "boost hose" + Venturi is all integrated within the red part of this diagram.

You could technically cut the big hose in half and run a can in between... but then you're pulling stupid vacuum on the can as well. The way it's set up for the MK7 retrofit, the can only ever sees whatever the TIP is generating vacuum-wise. Plus the little volume of boost from the Venturi.

Any chance you can see if it's possible to log the G950 sensor on your new GTI?


View attachment 301079


Ebay can though for reference... looks like they have an actual online store as well:
https://jackspaniaracing.shop/produ...volkswagen-mk7-golf-gti-2-0t-a3-tt-s3-8v-1-8t

For the record: The Tiguan hose does NOT seem to like to be twisted how it is. I question long term durability. It could eventually leak at some of the joints near the Venturi to hose connections, etc. Understand that if using for a retrofit, you might fuck up a $135 hose.

The hose going from the pcv to the inlet, or the hose going from the tip to the venturi?

 

[SYMAWD]

BMS TIP installed along with new oil cap and new oil pressure sensors (F1 and F378). Goal is for no more EPC light and not to find a bunch of oil in my intercooler.

Only thing is that all of the right turns on Thunderbolt are pretty mild. Turn 8-9 is the only place somewhat tight and it's nothing compared to the banked 180° on Lightning. Won't be back on Lightning for about a month.

 

[DerHase]

The hose going from the pcv to the inlet, or the hose going from the tip to the venturi?

The plastic hose that is part of the Tiguan hose/Venturi fitting. I'd be concerned long term about the plastic cracking, etc due ot the sideways pressure put on it to fit the can.

 

[DerHase]

 

[SYMAWD]

Good news and bad news from the track today after installing the BMS TIP, new F1 and F378 sensors, and new oil cap. The good news is there is no oil leak with the new oil cap and almost no oil at all in the intercooler pipes. The last piece of "good" news is I still had the same P164B/3B54 15188 code (oil pressure switch) on Thunderbolt, so while that means my problem isn't fixed, I can still test fixes without needing to go back to Lightning. In the video below, the first lap was my best for the day but at 4:59 you can hear the EPC warning go off in the sustained left turn. The first time today I got the P164B code, I also got a code (P25A9/3C47) for the piston cooling oil control but that was the first and only time along with (P0131/50B6) for O2 Sensor Bank 1 Sensor 1 and again that was the first and only time for that code.

I guess the next thing to try replacing is the N428 valve. Also, I am burning about 1/2 quart of oil per session, so 2+ quarts a track day seems excessive.

 

[DerHase]

Good news and bad news from the track today after installing the BMS TIP, new F1 and F378 sensors, and new oil cap. The good news is there is no oil leak with the new oil cap and almost no oil at all in the intercooler pipes. The last piece of "good" news is I still had the same P164B/3B54 15188 code (oil pressure switch) on Thunderbolt, so while that means my problem isn't fixed, I can still test fixes without needing to go back to Lightning. In the video below, the first lap was my best for the day but at 4:59 you can hear the EPC warning go off in the sustained left turn. The first time today I got the P164B code, I also got a code (P25A9/3C47) for the piston cooling oil control but that was the first and only time along with (P0131/50B6) for O2 Sensor Bank 1 Sensor 1 and again that was the first and only time for that code.

I guess the next thing to try replacing is the N428 valve. Also, I am burning about 1/2 quart of oil per session, so 2+ quarts a track day seems excessive.

I would strongly recommend testing oil pressure with a gauge, both low and high pressure stages (must actuate it to do so).

And maybe compression test and scope the cylinders. That's a LOT of oil to burn in a short time.

Perhaps low oil pressure = toasted rings/bad seal?

 

[Klrider44]

We shall see how the full retrofit does with my blaze intake and vortex XL.

 

[MonkeyMD]

Any interest in testing the MST inlet kit? I can ship you the TIP and hose once I get it removed as long as I get it back in one piece so I can eventually sell it haha.

That's what i have & it might be the cause of so my issues. Eventually will test the full retrofit, but not in the cards for now.