Exhaust routed, Sealed catch can system

[.FUDD.]

Just wanted to run this setup by you guys before i installed it and comfirm it will be suffecient and do the job!

M20 turbo on 12psi tuned via megasquirt and currently running a hose from the valve cover to the ground and venting to atmosphere and the fumes and vapor gasses are starting to become obnoxious!

I plan on running a hose from the valve cover to a sealed catch can, then a hose from the catch can to a one way check valve that screws into a metal bung that i have welded into my downpipe at a angle where it will create vacuum to pull the vapors from the crankcase and exit them out of the tailpipe instead of to the intake side, where i would worry about the gasses and fumes entering the turbo inlet and causinf issues as most people describe.


I have heard the discussion of peoples concerns in regards to not pulling enough vacuum through the exhaust but i am running 3" straight pipe from turbo back with no cats or mufflers... I will also be hooking up a vacuum gauge to test functionality and comfirm vacuum is present and suffecient.

Can anyone comfirm or have experience with this specefic setup. Any help is appreciated!

[IronFreak]

interesting idea but why go through all the extra work? just get a bigger can and empty it at oil changes.

[ak-]

interesting idea but why go through all the extra work? just get a bigger can and empty it at oil changes.

For a vacuum pull, which is ideal!
The important part of this system is how your check valve is angled in the exhaust. It needs to be welded on at a 45* or so with the tip entering the exhaust. There are a lot of ways to do this wrong. BFC's forced induction section has a couple threads of people doing this.

You should also make sure your hoses are large enough so you can move the gasses in a good manner that doesn't pressurize the crank case. Idk if I would run a hose to a sealed can to the check valve. What happens when you're not in boost, the gasses still need a place to escape no? I think if the can has a filter on it they would be great. Or weld another breather on the valve cover.

[.FUDD.]

I will defiantly be sure to run a large diameter hose to insure flow, And i am aware of the placement of the pipes position when welding it into the downpipe to insure vacuum pull. I may be over thinking this but i thought if i put a vented catch can that the air will pull from the area of least resistance so therefor i will be pulling more air in from the catch can breather than that from the crankcase? and in return....wouldn't this eliminate the "vacuum pull" effect? I think it would work more effectively like you mentioned if i welded another breather in the valve cover, That way it can breath at ideal but will i have an issue pulling vacuum still even though its on the valve cover and not at the catch can which is going to be in the middle of the system and i feel it will pull alot of air from this location and make the system less effective.

[.FUDD.]

Just to be clear... The check valve is screwed directly to the bong that is welded in the exhaust. So even at ideal it will have vacuum pulling on it and deposing of wasted fumes ect out the exhaust and the check valve will not let any air boost back into the crankcase. So i dont believe i would need a breather on valve cover or catch can correct?!?

[RoccoB517]

I run a venturi setup using the slash cut bung on my S/C M50 and it pulls plenty of vacuum to do the job.

[Sh3rpak!ng]

I started this thread on bimmerforums to try and "figure it out". There is a lot of very good info there - it turned into quite a technical discussion towards the end which I found very interesting.

thread: http://www.bimmerforums.com/forum/sh...-where-is-best

Anyway, I was originally experimenting with the setup on my NA s52 swap with the intention of adopting that knowledge onto my SCed e36. I never really got satisfactory results, but I also haven't been able to revisit it since to try a couple more ideas.

Post up your results after you test vacuum etc! I would love to see what you find.

[Sh3rpak!ng]

I run a venturi setup using the slash cut bung on my S/C M50 and it pulls plenty of vacuum to do the job.

can you elaborate? where did you put the fitting, which brand fitting did you use, what configuration, exhaust specs, did you do testing?

I am very curious since this will be my setup on my e36 eventually

[RoccoB517]

can you elaborate? where did you put the fitting, which brand fitting did you use, what configuration, exhaust specs, did you do testing?

I am very curious since this will be my setup on my e36 eventually

I am running a 3/4" rubber line from the valve cover to a catch can. From the catch can I run a 3/4" line with heat shield to a 45 degree slash cut with a check valve welded into the exhaust. My exhaust is a 3" side exit and the slash cut is welded in 24" from the outlet of the headers. I see 1.2 bar at idle and up to 3 bar at WOT at the catch can.

Also, I make my own fittings, but you can buy them and check valves from Moroso.

[RoccoB517]

Also, I'm running 12 lbs. of boost via a Vortech V3 blower, and using Raceland Euro long tubes, so the exhaust velocity is pretty high.

[Sh3rpak!ng]

I am running a 3/4" rubber line from the valve cover to a catch can. From the catch can I run a 3/4" line with heat shield to a 45 degree slash cut with a check valve welded into the exhaust. My exhaust is a 3" side exit and the slash cut is welded in 24" from the outlet of the headers. I see 1.2 bar at idle and up to 3 bar at WOT at the catch can.

Also, I make my own fittings, but you can buy them and check valves from Moroso.

Also, I'm running 12 lbs. of boost via a Vortech V3 blower, and using Raceland Euro long tubes, so the exhaust velocity is pretty high.

Interesting. I wonder if I'll be seeing much different results on the e36 with the blower vs the e30. I also run the euro raceland long tube headers -> magnaflow muffled x pipe -> vibrant resonators -> UUC RSC36 exhaust, all dual 2.25" tubes. The e30 is obd2 headers merged into a single 2.5" tube with a magnaflow straight through and a vibrant straight through at the end. It seemed that the vacuum pulled by exhaust velocity in the e30 wasn't enough to overcome back pressure past ~4k rpm, though I haven't gotten around to doing a real back pressure measurement

I also make my own fittings, though I did buy a vibrant kit to start with :D

[Sh3rpak!ng]

Where did you place your fitting?

[RoccoB517]

My engine is an M50 so it should be the same on your E36. The fitting is 24" from the header flanges pointed towards the passenger side, and on a 45.

[Sh3rpak!ng]

Interesting. I'll give it a shot on both the e30 and e36. I've been wondering about locating it closer to the exhaust ports. Looking at pretty much every configuration for the v8s (where I believe this setup originated from) they place the fitting in the primary collector.

Thanks


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