Catch Can run to Exhaust

[IBoughtAS13]

I sell catch cans. NO I AM NOT ADVERTISING ON HERE SO DONT BAN ME.

These cans are custom made and I am apart of the Supra community. Running lines to the exhaust manifold wont be as effective as pulling vacuum Pre-Turbo, also known as the intake pipe. You will actually be using vacuum to pull the fumes out of your crankcase. A quality can will trap the oil and keep every bit of it out of your intercooler pipes. My Supra customers are very happy and I don't have to tell anyone about what 2JZ's put out...

Where I sell Catch Cans.
Catch Cans/Fuel Rails Custom Made To Your Needs By Alfie Of VRP Racing Products

Here is a buddy of mine, the fuel rail on his RB25 NEO was done by me as well.
http://zilvia.net/f/chat/403069-rb25-neo-s14-swap.html

[wileymotorsports]

Ok so I just got my catch can installed like my original drawing. Now it seems to be sucking oil out of the crank and dumping it into the exhaust. My plan now is to "T" the crank line into the valve cover line and then into the catch can, so any oil will be caught before going into the exhaust. I didnt like the oil cloud my car left behind when I took off, even though I did feel alittle like James Bond, lol. Also my dad made a good point of why would you want to just suck oil out of your crank without returning it? Any ideas??? I know the exhaust is making enough vacuum but is it normal to suck oil out of the crank into a catch can????

[jr_ss]

If you don't have the line pulling a vacuum on the catch can you're going to get that. The catch can is suppose to be between the two so it catches all the oil vapor. If you have your VC going straight to your exhaust you're going to be bypassing the CC.

It should be Valve Cover -hose to Catch can - then line to exhaust check valve/venturi... You need to pull the crank case line off the exhaust line and install it to the line that goes to the CC. That should solve your oil in the exhaust issues.

[wileymotorsports]

So with the aftermarket catch can setups you have to constantly drain the can and add oil back to the engine? It seems like alot of oil comes from the crank and would fill the catch can quick.

[Kingtal0n]

Originally Posted by wileymotorsports

So with the aftermarket catch can setups you have to constantly drain the can and add oil back to the engine? It seems like alot of oil comes from the crank and would fill the catch can quick.

You should not add oil back into the engine from a catch can, unless you are absolutely certain that it is perfectly clean. A single bit of debris getting into any engine- specifically an SR20- can be disastrous. If you ever get a chance check out the size of the holes that oil the cam lobes. I could easily clog one with a nail shaving from my pinky and ruin the engine.


What you have is an oil control issue. The problem is either in the baffle of the valve cover, the type of vacuum being drawn, or the crank case pressure is rising unexpectedly. Did you mess with the one-way check valve on the intake side of the valve cover? Are you sure boost is not entering the crank case? Have you manually applied a vacuum to the valve cover with the engine off to see how easily it draws air from the crank case?

You may need to get creative with the baffle setup to prevent oil from entering your PCV system. If there is a significant amount of oil leaving the crank case, the solution is not going to be a catch can. Just having a can to catch oil all day long is not going to "fix" anything, it just means you will be throwing away oil unnecessarily.
I would do a leakdown test and verify your cylinders are sealing well, then trace the vacuum situation from the valvecover like I mentioned, find out where the air is going and how easily it flows from the crank case.

[wileymotorsports]

I would never add oil back into the engine from the catch can. I havent touched the check valve from the intake side. I had no problem with oil with the stock black can on. I have read that the black can on the exhuast side is more of a oil/air seperator then a catch can, with this removed it would make since to have oil in my lines. I know people remove the stock can, but what do they do about the oil just let it run into the catch can and then drain every once in a while?

[wileymotorsports]

Where would the crank case be vented to on this car??? My setup is similar to this but the intake side is stock on my car.

[jr_ss]

Wiley, that lower line on the drivers side of the block isn't necessarily a vent. It was actually used as a drain for the VC. Try routing the lower line through the can. If you're still getting too much oil, try blocking off that line. You should really only need to vent the VC and not the side of the block. There is a constantly oil cloud flying around in your bottom end and most likely you're drawing that out. You want to draw that out, through the VC to hit as much baffling as possible.

[cotbu]

I would never add oil back into the engine from the catch can. I havent touched the check valve from the intake side. I had no problem with oil with the stock black can on. I have read that the black can on the exhuast side is more of a oil/air seperator then a catch can, with this removed it would make since to have oil in my lines. I know people remove the stock can, but what do they do about the oil just let it run into the catch can and then drain every once in a while?

Most people that ditch the oem oil/air separator remove the hose with it. In that hose is a brass fitting that slows down the air and oil before it reaches the T

Originally Posted by wileymotorsports

Where would the crank case be vented to on this car??? My setup is similar to this but the intake side is stock on my car.

Why would you copy that setup? I see a lot of fail in that picture, maybe it's not finished there or something. Anyway.....

The "crank case vent" in that picture is either blocked off or T'd to the turbo's oil return.
Instead of trying to copy a picture, let someone here, help you put together a working setup. We are pretty creative!

[Boost_Fiend]

Everyone is talking about blow by like it is a normal thing. I thought this was signs of a unhealthy motor. before I rebuilt my sr I had excessive blow by. I though my can was set up wrong but it turned out to be bad rings. Now I am not seeing any blow any at all

[cotbu]

excessive blow-by is a problem, but oil in the intake, or aftermarket catch can is not always a sign of an unhealthy motor. Especially in this case, we aren't sure if it's his setup or an unhealthy engine, but routing that particular line to the exhaust is going to make it smoke for sure. I digress!
If they are not going to rebuild anytime soon, then I tend too not immediately suggest a leakdown test. The results always scare people. And having good results from compression test doesn't mean your engine is healthy.

[jr_ss]

There is always going to be some blow by no matter what. You'll always have air coming out of the oil fill hole, it's the amount of air escaping that makes it a concern. The engine is an air pump, and with the open valley in the front of the motor, it's going to allow air movement through the engine.

Now with that said, if you're moving tons of air through the oil fill hole, you have an issue.

Like I said previously though, he's sucking crank case air straight out of the bottom of the block and completely bypassing the catch can. Once that line is removed from the direct suction side and into the lines that run to the catch can he should be fine.

[wileymotorsports]

Ok Im cofused now, maybe Im making this more complicated then it is. I changed my setup so now the valve cover and crank case go into the catch can, wont I still have the same amount of oil being sucked from the crank line? I thought the crank needed to be under vacuum, if I block that line off how will the crank be under vacuum if Im just pulling it from the valve cover?

[jr_ss]

Essentially you'll still be pulling vacuum on the "crank case" even though you're pulling from the VC. If youre sucking up top, it'll pull up through the motor and valve cover(which you want it to do) and out to the catch can. Just try blocking that bottom line off first and see what it does.

I contradicted myself from what I said earlier... If you keep the lower line connected but pulling through the catch can, you'll still be pulling oily air out of the lower engine. However, you'll fill the can up continuing to have it plumbed that way.

[wileymotorsports]

Ok Ill give that a shot, wish me luck and thanks for all the help!!!!!

[jr_ss]

Any luck with the change?

[wileymotorsports]

sorry it took so long to post my results, Ive been super busy lately. I did what jr_ss said and blocked the crankcase line. Then routed the valve cover to the catch can, and from the catch can to the exhaust. So far I dont have any oil in the catch can or lines. So the setup is working great! Thank you for all your help.

[jr_ss]

Woot! Good to hear.

[4x4le]

wait, your blocking the only place for the crank case pressure to go. You may be blocking the oil from getting into the intake tract but your not getting rid of the crank case pressure. The only place for the crank case pressure to go now is up through the oil drains in the head which can lead to oil pooling in the head.

and if your running it to the exhaust, why does it need to go to a catch can?

[jr_ss]

You have a huge gaping hole in the front of the motor, oil is not going to pool in the head...

[boost addict]

So I'm in the middle of doing this now and are you saying its better to block off the fitting on the block where the stock catch went to and only route the vc to the exhaust?

[EsChassisLove]

Hook that shit up like this. Seriously. Any other way seems wrong.

[boost addict]

I know how a normal catch can is hooked up, I'm just routing mine to the exhaust instead

[jr_ss]

You can hook your oil drain on the side of the block to the can, but I would just use the driver's side ports on the VC to the can. Block the lower off, you have more than adequate sources to pull from. Besides you'll be pulling oily air from the lower engine and have it collecting in the catch can, in turn emptying the can more often. Let your VC do some work...

[tunermt]

I would strongly recommend running the valve cover lines and line off the block to the can and vent the can to atmosphere with a little filter.

Your exhaust (even post turbo) is pressurized, depending on the ID and mufflers usually only .5-1 psi but non the less under a slight amount of pressure at high RPM/Load. Not Ideal for crank case ventilation.

[4x4le]

here is how it was on my last setup



This is the valve cover that blu808 makes.

lower crankcase to middle port using the valve cover as a catch can and the engine gets to keep its oil, new rear port with baffle modded underneath ran to catch can (just in case) then ran back to the turbo inlet.

The new setup is having it ran to the exhaust

[PoorMans180SX]

Originally Posted by tunermt

I would strongly recommend running the valve cover lines and line off the block to the can and vent the can to atmosphere with a little filter.

Your exhaust (even post turbo) is pressurized, depending on the ID and mufflers usually only .5-1 psi but non the less under a slight amount of pressure at high RPM/Load. Not Ideal for crank case ventilation.

I don't think you understand. You must use a jet in the exhaust when running your catch can to it. It works like a carburetor, drawing crankcase gases out by using the velocity of the exhaust gas.

Not to mention routing it to your intake/exhaust is much better than atmosphere vent.

[jr_ss]

Originally Posted by PoorMans180SX

I don't think you understand. You must use a jet in the exhaust when running your catch can to it. It works like a carburetor, drawing crankcase gases out by using the velocity of the exhaust gas.

Not to mention routing it to your intake/exhaust is much better than atmosphere vent.

Exactly. There's a checkvalve on the end of the Venturi to keep the exhaust pressure from filling your engine. Putting a vacuum on your crankcase has proven to help seal rings and increase HP output.

[Big Zee]

you guys have totally lost me, blame it on the blonde hair I guess.

Wouldn't a S13.4 VC negate the need for a catch can altogether ? I am having one built and was going to run a breather setup to the middle port, the rear exhaust port to Crank Case, and the PVC to whatever it hooks up to.

[jr_ss]

Originally Posted by Big Zee

you guys have totally lost me, blame it on the blonde hair I guess.

Wouldn't a S13.4 VC negate the need for a catch can altogether ? I am having one built and was going to run a breather setup to the middle port, the rear exhaust port to Crank Case, and the PVC to whatever it hooks up to.

Not at all... Any engine can benefit from a properly working catch can setup. That's like saying S14/S15 guys don't need to run one because of the VC they already have.