BMS Catch Can Install

[9vapors]

Most of us know the benefits of installing catch cans on modified vehicles, or just turbo vehicles in general. The heads, intakes, intercoolers etc get coated in oil vapor which builds up causing issues and costly maintenance. Possibly worse if you consider over time it will affect the octane of vehicle, which if tuned to a certain octane, would be bad. That said, they don't make a complete kit for our vehicles that I've found. Which brought me to the M5 kit. At least it was made for the same motor and parts, just differently configured.

Some folks on here before have made their own catch can setups, which I admire, but I wanted the ease of the custom cnc/andodized black BMW fittings included in the BMS kit. I reached out to them and asked if they would just sell the fittings. The answer was no. I am not too upset though, as the cans and fittings are made in the USA and are flawless, easy to empty and are all around solid.

So, to start I knew I would need more hose, but began to fit the kit and saw that the mounting location I originally planned on was going to need some work. I also have RK intakes and believe this would require aftermarket intakes, but not sure for our vehicles entirely.

Parts list:
3/4 heater hose 6ft worth
(PEX) Hose cleaver (for straight cuts)
Plastic epoxy/weld
1 1/2" spacers
6M x 60mm bolts of some sort

These are the cleavers I had used, they cut both the reinforced silicone and rubber heater hose perfectly.

[9vapors]

The left side was pretty straight forward, I did have to trim the silicone hose, that connects to the install elbow. The routing works for me, because I have a PTP turbo blanket, wrapped and coated catless downpipes, so no need to run the engine cover. If you like the engine cover look, it would be pretty simple to route the hoses differently to accommodate. I only need to twist the flapper/ccv line slightly to work in this configuration.

[9vapors]

The right side was a bit more interesting. I was using my big boy muscles and torqued the intake elbow a bit too much, and although I saw other folks have done the same, I still broke off the elbow. In doing so, it allowed me to epoxy it back on in the opposite direction completely simplifying the right side install. I needed to trim the silicone hose to point in the right direction, then added the longer hose routed under the intake. Was a 30 minute detour.

[9vapors]

All done! I noticed loading this on mobile, the pictures are all over the place, so if you have any questions, I'll be happy to answer.

You might notice I deleted a lot of clutter from the engine bay. I rerouted wiring and vacuum lines as well. Makes working on things much easier.

Lastly, sorry for the absolutely filthy engine bag… I'm waiting on a couple more things and I will get that done…

[Chilled]

nice, stealth and oem looking. Like the RK intakes.


Question, does anyone have doco or can explain how our PCV systems actually works. Especially around positive/negative pressure(vacuum).

Just looking around and it looks like ours got an update where this upper PCV hose does not have a connector to the lower valve cover. And this hose only has the flapper valve for boost, no other check or pressure valves.

Wonder what is the point of the whole system and if it would be possible to block off the intake elbows and just have the bearing catch can.


*Edit* did find these. After skimming through, doesn't really explain why we couldn't do the intake elbow block off.

https://www.xbimmers.com/forums/show...1516064&page=2
https://www.xbimmers.com/forums/show...1516064&page=2
https://www.xbimmers.com/forums/show....php?t=1245651

[9vapors]

Crank case ventilation under boost. Those gasses that build up and blow by are sent back into the intake to get burned again, however they're oil/gas vapors that gunk everything up. The S63TU is much better with this and has an internal oil return for the liquid, but still kicks the vapors back to the intake. Adding the catch cans just runs it through another strainer to keep the gases clean as possible when they enter the intake again.

You're asking why couldn't we just add an air filter off of the valve cover and eliminate the intake elbow? I believe that the connection to the intake is sucking the air in and helping pull the vapors/gases out of the crankcase.

You could easily improve on that accordion style, brittle pipe they use by replacing it, when mine cracks I'll definitely be going that route. I'm sure there is a better replacement for the flapper valve as well, but I'm unsure of the spring rate/vacuum pressure.

[Chilled]

Originally Posted by 9vapors

You're asking why couldn't we just add an air filter off of the valve cover and eliminate the intake elbow? I believe that the connection to the intake is sucking the air in and helping pull the vapors/gases out of the crankcase.

You could easily improve on that accordion style, brittle pipe they use by replacing it, when mine cracks I'll definitely be going that route. I'm sure there is a better replacement for the flapper valve as well, but I'm unsure of the spring rate/vacuum pressure.

In a nutshell yes, have a tiny breather filter of the valve cover. It would be done via a catch-can but, yeah.


I was watching this guy explain the PCV system, on the older S63. Interesting, He mentions the intake creating a vacuum whilst under boost.

Granted, I have never built anything crazy. I have never connect a breather hose/catch-can to the intake pre-turbo, nor have seen anyone do it. I have seen people highly recommend not to. Hence why I am struggling to understand that flapper valve, the separator thing in the valve covers/other parts and the relevance to boost/vacuum.

Does the combination of those valves/flappers create the relevant vacuum in the engine or? How does it control if there is too much vacuum or positive pressure?

[9vapors]

Yeah, that flapper I believe is just a sort of one way valve. Opens under vacuum, would close to keep the system from receiving back pressure. I could be wrong, but I don't see it working as a pcv or anything. I was reading some about blocking off the ccv, found this awesome thread worth looking at. I think what he has blocked off though is what has been removed from the newer motor though, but might be what you're referencing. In other words, we only have one line from the crankcase, and it goes to the intake elbow.

X5M Mid Life Overhaul https://www.xbimmers.com/forums/show....php?t=1658852

[Chilled]

Saw that, he only blocked off the lower hose, and yeah think that one was removed from our engine. He kept top one connected to the pre-turbo via catch-can. "The catch cans allow crankcase pressure to vent to the intake of the turbos,"

What Ideally I would like to do is zero connection back to the intake. Catch-can straight to valve cover. But it seems no one is doing that.

[9vapors]

Yeah, I don't think there would be any vacuum that way. I'll be sure to report back after a few thousand miles. Hopefully I'll see that it working well. That guy in the thread I linked was filling his. Again, different motor, but still crazy.

[Chilled]

Originally Posted by 9vapors

Yeah, I don't think there would be any vacuum that way. I'll be sure to report back after a few thousand miles. Hopefully I'll see that it working well. That guy in the thread I linked was filling his. Again, different motor, but still crazy.

Let us know.

I did see a post from Sophisticated Redneck About having idle issues without connecting to the inlet. Redneck, did you end up doing anything interesting with your catch-can? What about the adjustable valve?

[Cbozz]

I actually just installed my catch cans... curious to see how much oil it will actually catch but I did find a minimal oil around the inside of the turbo inlet so hopefully that will mitigate it!
I also added a vargas oil filler cap crankcase vent to air and that is noticeably keeping the engine temps lower.

[Sophisticated Redneck]

Originally Posted by Chilled

Let us know.

I did see a post from Sophisticated Redneck About having idle issues without connecting to the inlet. Redneck, did you end up doing anything interesting with your catch-can? What about the adjustable valve?

Didn't see this post until now. I've gone through a bunch of different setups as on the previous gen M's & 50i's (E70)you had connections that went to the lower intakes there were under both boost or vacuum depending on the driving conditions and it was a much more complicated setup then the F85's, complete with flapper valves and one-way check valves embedded in the CCV tubes along with cross-bank connection tubes....needless to say its an over engineered complicated mess. Luckily for the F85 BMW made it much simpler. I never experienced any issues with idle on any setup that blocked the CCV inlets on the turbo intakes.

I am currently running a setup that directs all CC gases through catch cans with sintered bronze filters then direct to a Moroso crankcase evac system in the exhaust. So there is zero CC gases being reintroduced to the engine. And yes of course I only drive this way off-road on a closed course in Mexico. I haven't seen any drawbacks to this system yet, and the header evac system pulls a few pounds of vacuum under full throttle, which is about the same as what the intakes pull under full throttle. The intakes are completely free of any oily residue now and I have noticed a slight bump in timing. I also believe this system can save your rod bearings as IMHO the reason why this platform suffers from random rod bearing failure is due to LSPI (Low Speed Pre-Ignition) constantly bearing on the rod bearings through oil film failure under LSPI events caused by high-boost low rpm + oil intake gases, espeically those running tunes.


Now if I had a F85 and I wanted absolute performance, zero oily blow-by gasses in my intake, decreased chance of LSPI, and was not worried about emissions compliance I would:

1 - Cap the CCV ports on the turbo inlets

2 - Install catch-cans of your choice (recommend the units with the Bronze sintered filters, catches everything, even water vapor).

3 - Install Moroso crankcase evac kit and run the output from the catch cans to the evac kit.

Catch cans may seem redundant if you are just pumping all the CC gases out the exhaust but in reality it is just as important to keep your exhaust from smoking under heavy throttle from the burning of the oil residue.

I will take the time to write up and post on how I installed the Moroso crankcase evac kit using a method that doesn't require any welding under the truck as the exhaust on the E70 is identical to the F85 if there is enough interest.

[Sophisticated Redneck]

Originally Posted by Cbozz

I actually just installed my catch cans... curious to see how much oil it will actually catch but I did find a minimal oil around the inside of the turbo inlet so hopefully that will mitigate it!
I also added a vargas oil filler cap crankcase vent to air and that is noticeably keeping the engine temps lower.

Keep us posted on how this setup works out. I have tried out similar setup on the E70 and but the amount of smoke coming out the breather was just to much. It was on a engine with over 150K miles at the time so a much newer F85 might not have that much blow-by so possible it wont be an issue and if it works will be a nice alternative setup.

[Cbozz]

Originally Posted by Sophisticated Redneck

Keep us posted on how this setup works out. I have tried out similar setup on the E70 and but the amount of smoke coming out the breather was just to much. It was on a engine with over 150K miles at the time so a much newer F85 might not have that much blow-by so possible it wont be an issue and if it works will be a nice alternative setup.

There is no smoke at all... I had it on for about 4 months and can't smell anything or see any smoke in the engine bay... that oil cap breather is definitely a good buy.

[9vapors]

Just ordered one as well… they're on sale!

[Chilled]

Originally Posted by Sophisticated Redneck

1 - Cap the CCV ports on the turbo inlets

2 - Install catch-cans of your choice (recommend the units with the Bronze sintered filters, catches everything, even water vapor).

3 - Install Moroso crankcase evac kit and run the output from the catch cans to the evac kit.

Catch cans may seem redundant if you are just pumping all the CC gases out the exhaust but in reality it is just as important to keep your exhaust from smoking under heavy throttle from the burning of the oil residue.

I will take the time to write up and post on how I installed the Moroso crankcase evac kit using a method that doesn't require any welding under the truck as the exhaust on the E70 is identical to the F85 if there is enough interest.

Hell yeah, would be interested in this write up.


So when you say 1. "Cap the CCV ports on the turbo inlets" your talking about the port near the flapper valve just past the maf sensor.


Curious, as to why you dump this into your exhaust thro. Why not just put a secondary breather/overflow hose under the car and just let it go out like a radiator overflow. (All off-road/race use only). Is that so the Moroso evac sys uses the exhaust gases to create a -negative pressure for the ccv and pulls the gasses out. Similar to what the flapper/intake valve would be doing.

[rafael2020]

Originally Posted by Sophisticated Redneck

Now if I had a F85 and I wanted absolute performance, zero oily blow-by gasses in my intake, decreased chance of LSPI, and was not worried about emissions compliance I would:

1 - Cap the CCV ports on the turbo inlets

2 - Install catch-cans of your choice (recommend the units with the Bronze sintered filters, catches everything, even water vapor).

3 - Install Moroso crankcase evac kit and run the output from the catch cans to the evac kit.

Catch cans may seem redundant if you are just pumping all the CC gases out the exhaust but in reality it is just as important to keep your exhaust from smoking under heavy throttle from the burning of the oil residue.

I will take the time to write up and post on how I installed the Moroso crankcase evac kit using a method that doesn't require any welding under the truck as the exhaust on the E70 is identical to the F85 if there is enough interest.

I'm also interested.

[Viper501]

Originally Posted by Sophisticated Redneck

I will take the time to write up and post on how I installed the Moroso crankcase evac kit using a method that doesn't require any welding under the truck as the exhaust on the E70 is identical to the F85 if there is enough interest.

Yes please.

[Blue By You]

Originally Posted by Cbozz

I actually just installed my catch cans... curious to see how much oil it will actually catch but I did find a minimal oil around the inside of the turbo inlet so hopefully that will mitigate it!
I also added a vargas oil filler cap crankcase vent to air and that is noticeably keeping the engine temps lower.

Which catch can kit did you install? Where can I find it?

Is this the Vargas oil cap you're using? Should I buy it direct? Is it completely plug and play like screwing on the OEM cap? Which option did you click? https://vargasturbo.com/product/vtt-...case-breather/

[9vapors]

Originally Posted by Blue By You

Which catch can kit did you install? Where can I find it?

Is this the Vargas oil cap you're using? Should I buy it direct? Is it completely plug and play like screwing on the OEM cap? Which option did you click? https://vargasturbo.com/product/vtt-...case-breather/

Stock valve cover, and that's the one. You unscrew your cap and this goes in the same way, just turn until it locks in place, just like your stock cap.

[Blue By You]

Originally Posted by 9vapors

Stock valve cover, and that's the one. You unscrew your cap and this goes in the same way, just turn until it locks in place, just like your stock cap.

Got the cap, thank you.

Turner/ECS is telling me that I only need one catch can. But I notice you guys are using two. You went with the SpeedWow one right? Any specific reason why?