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My new crankcase evacuation system

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99gst_racer

Moderator
11,976
1,542
Apr 5, 2003
Coloma, Michigan
I spent quite a bit of time setting this up this past winter and spring. I finally got it the way I like it, and I figured I'd share it with everyone else.

I'll start with the valve cover. All machining was done by my buddy Evan and myself. We shaved the lettering and the oil cap boss (I'll discuss this more later). We also punched two holes through the top for vent ports.

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After that, I removed the factory baffle from the underside and began mocking up my version of a baffle system. I basically wanted to be able to remove the factory baffle to clean underneath it, and I couldn't come up with an good way to reattach it. So, I decided to make my own. When we punched the holes through the top, we did it directly above the cam towers. This will give me an area where oil isn't being slung. We just had to weld in two small pieces of aluminum on each side of the hole to deflect any oil being slung up by the cam lobes.

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After all the machining was done, I had my welder weld in a few bungs here and there. We used -10 ORB (o-ring boss) bungs on the top, and a 2" Pro-Werks 2" cap & bung assembly for an oil cap. This thing is SWEET, by the way. No more leaking oil past the cap gasket like the factory ones usually do. We had to machine off the locking assembly for the factory cap, and weld on a threaded ring in it's place. The cap itself is a black anodized, billet aluminum cap with an o-ring seal.

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A few pics of the bungs and fittings prior to welding them in place:

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Here's a few pics of the valve cover after being powdercoated and clear coated by Carlos of Tirado Custom Coatings. Turned out beautiful, if you ask me. :)

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* Also notice that we took the time to completely eliminate the side factory ventilation port. This involved filling in the hollow bubble from the underside, and hand filing it down to match the side contour of the valve cover. It probably took more time than it was worth, but I did it anyway. :p


With the valve cover finished, it was time to look into a worthy catch can. I had plans to buy an aluminum coolant overflow tank and completely modify it to suit my needs. And then I came across Craig's large filter catch cans. These cans are much nicer and are far more advanced than what I had originally planned, so whether or not to buy one was a no-brainer. ;) Pictures don't do these justice - they're gorgeous.

Here's a pic of mine before being polished. -10 inlets on the top and a -12 outlet on the front.

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I welded a bracket on the backside and mounted the can in the area that the fuse box is typically located for a 2G.

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These pictures also show my one-off 4" carbon fiber intake tube. It was handmade by Chris (gixrman) for my compound set-up. Being that I didn't have him incorporate a fitting into the side of it when it was made, my best option was to use a bulkhead fitting to attach the -12 hose. I borrowed the fitting design that many manufacturers use to evacuate the crankcase via the exhaust system. I'm hoping this will help scavenge and put a vacuum on the catch can and crankcase. I'll eventually wire in MAP sensor to datalog it's performance.

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Here's how it all looks as of about an hour ago:

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Feel free to comment and/or post any questions.
 
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Such a simple solution for the VC baffle. I'm diggin' it. You'll have to measure how much oil you get in your can vs. miles - but I'm thinking that your solution will work quite well. Did you play around with the height of the new baffle or did you just ensure it was of low enough height and went for it? I'm sure a perfectly calculated angle + length would be ideal, yet a negligible improvement over just cutting up some metal and just welding it down.

Are you concerned at all about the CF cracking where that bung is located? I'm sure if the cut was clean and the nuts are tight it should be fine. I'm also thinking your solution for vacuum to the VC will work just dandy and I'm surely interested in the MAP sensor results. The "hole" faces the compressor inlet, right? It's hard to tell from the photo.

All in all, an excellent example - as always.
 
I see that this system will relieve crankcase pressure under boost conditions. I don't understand what will be happening with crankcase pressure when you are in a no boost or manifold vacuum condition.
 
Such a simple solution for the VC baffle. I'm diggin' it. You'll have to measure how much oil you get in your can vs. miles - but I'm thinking that your solution will work quite well. Did you play around with the height of the new baffle or did you just ensure it was of low enough height and went for it? I'm sure a perfectly calculated angle + length would be ideal, yet a negligible improvement over just cutting up some metal and just welding it down.
Yeah, the can has a nifty sight glass to keep an eye on the oil level inside. I plan to track mileage and I'll pull it out and drain it at first sight of the oil level through the glass. I've only got about a dozen miles on it so far...

Yes, shaping those baffle pieces did take some time. My initial cuts were very close because I had used cardboard pieces on an initial mock-up. But after they were welded in place, I did have to clearance them for height to assure that the cam lobes would not come into contact with them. And I cut away at the sides a little bit to help provide more space for air to move around them. All in all, they fit good and tight inside there and should deflect enough oil away from the port, while still allowing air to make it's way to the port.

Are you concerned at all about the CF cracking where that bung is located? I'm sure if the cut was clean and the nuts are tight it should be fine.
The CF was surprisingly a breeze to drill into. It cut clean and there wasn't any cracking issues. It's got a pretty thick wall surface, so it's a pretty tough pipe. The bulkhead nut is actually loctited on just to prevent it was backing off and being sucked into the compressor.

I'm also thinking your solution for vacuum to the VC will work just dandy and I'm surely interested in the MAP sensor results. The "hole" faces the compressor inlet, right? It's hard to tell from the photo.
The hole actually faces the direct the air is coming from. That way, incoming air can pass through the fitting, hopefully scavenging the air inside of the lines and catch can. It's pretty much exactly the same way you would use the exhaust system to scavenge, but I feel I'll have better results using the pre-compressor intake pipe rather than the exhaust system.
 
I see that this system will relieve crankcase pressure under boost conditions. I don't understand what will be happening with crankcase pressure when you are in a no boost or manifold vacuum condition.
There are no check valves or anything of that nature, so it's not a directional system. If it needs to, the crankcase can pull fresh air in through the catch can and lines just the same.

My goal with this set-up was to have something to effectivily evacuate the crankcase while boosting. I run 40+ psi boost, so it's pretty important that I have something that will function well at that boost level. I'm pretty confident this will do the trick.
 
Just the sickest ####ing setup ever. I don't give a ####. Everything in your bay is just MINT and sick as hell. It's all just perfect and makes me almost pissed off cause my car isn't done yet. I need a custom VC like that...someone see this post and fab me one! Anyways, sick ass car and I'm glad that you live in Michigan.
 
Just the sickest ####ing setup ever. I don't give a ####. Everything in your bay is just MINT and sick as hell. It's all just perfect and makes me almost pissed off cause my car isn't done yet. I need a custom VC like that...someone see this post and fab me one! Anyways, sick ass car and I'm glad that you live in Michigan.
Thanks, man. Much appreciated. :D

Yeah, I wish I owned my own vertical mill. I would love to be able to offer valve cover machining services to others.
 
Very cool idea on the VC baffles Paul! Nothing better than following the KISS formula. ;) (And I love the replacement cap too).

This is the first pic I've seen of the turbo setup coated and installed, and it is just wicked looking. Can't wait to hear more on how everything works.
 
i like the threaded oil cap. the stock design is a PITA to get to hold down tightly over time. good stuff!
 
That looks really nice. I can't wait to see some results of how it works, are you planning to place a boost gauge on your crank case to verify that you are able to maintain vacuum?

I still need to check mine and I recently added one 5/8" vent line and mine is going to an exhaust scavenging fitting on my down pipe and not to my intake. I don't want to thread jack you but I can post pictures of mine if people are interested. Either in here or in another thread.
 
Thanks, guys!

BTW - Where did you get the Pro-Werks cap and bung? Got a link to it?
I'm a Pro-werks dealer, so I just grabbed one from work. :sneaky:
They're not cheap, but they sure are nice. The ring welds well, too. I could only imagine how well your welder could do with one. ;)
 
That looks really nice. I can't wait to see some results of how it works, are you planning to place a boost gauge on your crank case to verify that you are able to maintain vacuum?
I plan to have a 3-bar MAP sensor plumbed in right at the VC port. That way I can datalog it performance, and not worrying about keeping my eye on yet another pressure gauge (I already have two cockpit mounted boost gauges as it is). :)

I still need to check mine and I recently added one 5/8" vent line and mine is going to an exhaust scavenging fitting on my down pipe and not to my intake.
Have you ever mounted a pressure gauge on the exhaust to measure the draw? From what I've gathered, many (if not most) turbo engines aren't sufficient for evacuating the crankcase via the exhaust. Many guys have measured vacuum in the downpipe on a DSM and haven't been able to reach a full inch of vacuum. It seems that most of us are running pretty large exhausts that create a slow speed exhaust. This slow speed doesn't allow the pressure to drop low enough to be beneficial for crankcase evacuation. But like I said, it might be worth measuring yourself as every car is slightly different. In theory, you could bottleneck your exhaust to speed up the flow and that would create a venturi that might allow a great enough pressure differential to evacuate the crankcase - but at that point, you're creating a potential exhaust restriction, so I really wouldn't say it would be worthwhile trade-off.

But if you've already done some measuring with your set-up, I'd love to hear more details about it.
 
Nice work.

I'm actually 5 Min away from starting my setup. I like the way yours is done, but i plan on doing mine a bit differently because i want to retain the factory baffle.
 
I plan to have a 3-bar MAP sensor plumbed in right at the VC port. That way I can datalog it performance, and not worrying about keeping my eye on yet another pressure gauge (I already have two cockpit mounted boost gauges as it is). :)


Have you ever mounted a pressure gauge on the exhaust to measure the draw? From what I've gathered, many (if not most) turbo engines aren't sufficient for evacuating the crankcase via the exhaust. Many guys have measured vacuum in the downpipe on a DSM and haven't been able to reach a full inch of vacuum. It seems that most of us are running pretty large exhausts that create a slow speed exhaust. This slow speed doesn't allow the pressure to drop low enough to be beneficial for crankcase evacuation. But like I said, it might be worth measuring yourself as every car is slightly different. In theory, you could bottleneck your exhaust to speed up the flow and that would create a venturi that might allow a great enough pressure differential to evacuate the crankcase - but at that point, you're creating a potential exhaust restriction, so I really wouldn't say it would be worthwhile trade-off.

But if you've already done some measuring with your set-up, I'd love to hear more details about it.

I actually have not mounted a pressure gauge to my exhaust yet and you bring up some good points. Currently my car is limping around with a blown PTE turbo on it so I will be able to actually take measurements under boost in a week or two after I finish with school and have time to install my HX-35.

I started a new thread to show the method I used to keep the factory baffle in place. I think it should work for my application as I am only pushing 30psi max but your setup is for sure more all out race car friendly.
 
I have come to expect nothing less from your threads. If you ever post one in which you dont re-invent the wheel in some way I am going to be very disappointed. LOL

As always you have done an impressively clean job with that set up, as well as your whole engine bay. its rare anymore that I bother to pick up a import rag,( lets be honest most of them are crap) but I cant think of many cars more deserving of a build feature than your dsm. You have done an amazing job with every part of this build. Keep at it!

If there were ever a dsm i would kill for....
 
Just curious why you don't have the hose going to the exhaust rather than the compressor inlet? If I'm thinking about this correctly then you are going to also be pushing oil through this hose when the crankcase is under extreme pressure which will then go through the intake and possibly cause ignition issues. On my camaro we ran these hoses down the headers so any oil sucked through would just cause a little blue smoke but not be pushed through the cylinders.
 
Just curious why you don't have the hose going to the exhaust rather than the compressor inlet? If I'm thinking about this correctly then you are going to also be pushing oil through this hose when the crankcase is under extreme pressure which will then go through the intake and possibly cause ignition issues. On my camaro we ran these hoses down the headers so any oil sucked through would just cause a little blue smoke but not be pushed through the cylinders.

From what I've gathered, many (if not most) turbo engines aren't sufficient for evacuating the crankcase via the exhaust. Many guys have measured vacuum in the downpipe on a DSM and haven't been able to reach a full inch of vacuum. It seems that most of us are running pretty large exhausts that create a slow speed exhaust. This slow speed doesn't allow the pressure to drop low enough to be beneficial for crankcase evacuation.

And the catch can should catch most of the oil.
 
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