Thread: Confused with oil separator system

Hey guys, I recently dynoed my car and the guy recommended I move around some hoses on my oil separation system. I made some ghetto pics to make it easier to understand.

THIS IS WHAT I CURRENTLY HAVE. Bascally there is a breather filter on the T on the valve cover


WHAT THE DYNO SHOP SUGGESTED. Remove that filter and run a hose from there to the intake pipe before the turbo. He said the added pressure will expand the piston rings more yeilding more power.



ANOTHER SETUP. I'm looking at pics of turbo setups and I've seen something like this on a couple of them. Would it work?


Any advice or another setup you suggest is greatly appreciated.

I don't think the last one you show would work. You want the oily air to pass thru the catch can. the way you have it shown there, the catch can is acting as a filter. I think that you need to keep the oil separator between the VC and the block. I'd put it in line where the stock separator tank goes. I've been rethinking the routing on my PCV, and that's where I'm going to put my GReddy can at. Anyone have a pic of a stock DET routing setup? As I understand it, it would work at a push/pull system, but i'm not sure of how safe it would be to allow pressurized air to enter at the location where your breather filter is now. You'd have pressure from the crankcase as well as pressure from the intake, which isn't good. I'm glad this came up...

All of those are pretty bad ideas actually, well Greddy catch can is not too bad, but you will have to empty it out.

First, take a look here. This system should work perfectly for both NA and Boost.

Whats wrong with the diagrams.

Diagram 1: Metered air is being released into the atmosphere, and unmetered air is being sucked in (depending on the engine load). Along with that you will see oil on your transmission because the breather will be leaking oil.

Diagram 2: This is a terrible idea. A, there is a reason why stock system directs the pipe after MAF, because that air is metered. B, oily blow by vapors will oil up your tubing and turbo.

Diagram 3: This one is the most acceptable, but you will have to worry about cleaning out the oil catch can and adding loosing oil out of the crank case.

Diagram 4: The best you can do is this:

I've been paying attention to your thread and write-up, but there seems that there are so many people using different configurations. So I'm not sure on how to do this.

Hopefully there will be more input here, but so far I'll go with your idea, vadim.

Lol yeah I hear you on that. The best thing to keep in mind is the whole Metered and unmetered air deal. ECU knows how much fuel to throw in at a specific air ratio, but if that air ratio is messed up, then well your car won't run quite as well.

But yeah I agree on extra feedback, hopefully more experienced SR modders can chime in

I wish it was my idea, I just redid what someone else did and took more pictures hehe.

Vadim is right, you must take into account metered air! Not only that but you have to look at pressures. The whole point is to reduce crankcase pressure to make more power and reduce oil consumption. You can make more power by taking advantage of the turbo's ability to suck in air. How? Simple. Use the Turbo to suck in the blow by gas AFTER it has been filtered by a catch can. This will reduce pressure in the crankcase significantly. On really high power cars you can route the PCV to the exhaust system and use the exhaust system to create a vacuum which will pull out crankcase gas. But you don't wanna do that on a street car, it consumes a lot of oil and emissions are even worse.

Right now I have my vc vented to atmosphere, but if I had a decent catch can I would route the blowby to that and then back into the intake just before the turbo. I can make a diagram if you like.

Interesting experiment. Take a drink that you get at any fast food restaurant. Like Mcdonalds. Now with your drink filled up blow across the top of the straw really hard. It is easier if you use a compressed air nozzle. By blowing hard enough you can cause the soda to climb up the straw. This creates a vacuum. The higher the velocity of gas rushing across the straw, the more vacuum is created.

Do this same thing on your car. Put the filtered blowby (from the catch can) into the intake tract just before the turbo inlet. The rushing air from the turbo sucking (not to mention the vacuum normally created by such) will pull a lot of filtered pcv gas back into the intake. This is most effective on a pull through setup, but with a check valve it works well for blow through as well.

Perhaps this is a horrible description, but try the experiment and you will see what I mean. It is all in physics.

The 1st one will work, but not the most effectively. The 2nd one will work, again not the most effectively. Take the second pic and route the catch can back to the intake instead of by the maf on the pressure side...

3rd one won't work, the catch can is routed to the pressure side. You want to route it to a low pressure side. If you had it set up that way you would blow your dipstick into orbit.

I made a separator from a beer can for my car this is how it is kinda routed. (As far as routing goes I think this is what the other guys are saying too). Oil separators have a very simple design. They are for the most part a piece of pipe with a plate in the middle. The OE separator has two plated inside it and that is all.

Coheed,

Good point on making the turbo suck out the blow by!

I can see how this will work flawlessly on Drawthrough setup, but with Blowthrough you would have to stick the hose before the MAF/Turbo, and won't this technically make you gain/loose some metered air?

I mean I've never noticed the T connection sucking in any air, I've only felt it blowing some air, so maybe thats not as big of an issue?



So cars and beer do match after all!

Interesting design, I like it a lot actually. The oil drips back in the crankcase right?

Regardless, you don't actually want the nipple that has the breather on it currently, to be in the path of compressed air, like shown in your last picture. Don't ask me how I know

I just run a catchcan off of the nipple you have the breather on, and then on the other port on the catchcan, I have a breather filter.

I don't have a catchcan running from the valvecover to the block. I run a straight hose between both points. The stock catchcan doesn't really prevent any oil from entering back into the block, from what I could tell. I haven't opened mine up to verify, but I'm thinking all it is is a mesh type of material in the catchcan to pick up any debris, and the oil just enters back into the crankcase.

You almost always want to have a catchcan in the system when boosted, especially in the second image you posted, with a direct line to the intake pipe pre-turbo. This is bad IMO, because you're simply sucking all the oily blowby right into the compressor inlet, and this will in turn end up in your intercooler piping. I don't know if it would do any damage to the fins on the wheel, but I could see it causing damage if you have any FOD entering the intake from the valvecover.

Vadim-

Your picture you show is bad for FI, IMO. You're compressing the crankcase with boost, in the setup you show. The PCV is supposed to prevent crankcase buildup, on N/A applications. When you hit boost, the PCV stays shut, not allowing any compression to be released, which in turn compresses the crankcase even further.