Catch Can run to Exhaust

[wileymotorsports]

I was searching different ways to route the catch can and came across some guys running one line to their exhaust instead of the intake tube. I would rather route the catch can into the exhaust then back into the intake. So I made a super advanced drawing of what I would like to do. Will this work? The "T" fitting on the left side is replace with a 90 Degree elbow then routed to the catch can, the PCV will tee into that line and the crank breather line will tee into the line from the catch can to the exhaust.

32521

[PoorMans180SX]

Yeah, you can do that, but it's not very effective. You'll pull better vacuum and make more power with it in the intake before the turbo and after the maf.

[Josh]

or you can just reroute it to the oil pan...

[wileymotorsports]

I know a ton of guys run the catch can to the intake, but wont that eventually coat the inside of the intercooler with a film of oil or does the catch can prevent any oil going back into the turbo? Wouldnt you loose power if you send oil soaked air back into the engine upposed to fresh air? Sorry for all the questions, my car has no vacuum now it just has a small filter on the front of the T coming from the vavle cover and I would like to get that fixed.

[wileymotorsports]

or you can just reroute it to the oil pan...

Dont you need vacuum, for the catch can to work properly?

[EsChassisLove]

If you have a HIGH QUALITY catch can with HIGH QUALITY baffling inside, along with a healthy engine, you won't ever need to worry about oil on the turbo, pipes, intercooler ect.

I make it a habit to check mine weekly.

Edit-But to answer your question, Yes. If you dont have a proper setup and a good catch can, you will get oil in there most likely. My T25 and Throttle body had a good coat of oil caked on the fins and butterfly valve with the OEM set up. Didn't help i had blow by on some pistons though.

[KAT-PWR]

you can vent pcv and valve cover through a catch can to atmosphere. It moves enough air. But yes to intake pre Turbo post maf is best as you are actively pulling air out. A high quality can with internal baffling is best. EBay cans are shit even if remote mounted somewhere cool.

[wileymotorsports]

Any suggestions on a catch can??? What about running steel whole in the can? If I run it to the intake do I still need a check valve?

[jr_ss]

Steel wool, will effectively trap airborn oil vapor... The only problem with routing back to the intake side of the turbo, is the chance of lowering your actual octane rating with the oil in the air. A sealed catch can with a vacuum on it and the crankcase will net high power numbers than a vented to atmosphere can will.

You can get a check valve and Venturi for the exhaust setup through summitracing. I'm actually going that route on my VVL conversion. The venturi will pull the vacuum you need once the turbo is spooled. Spooled is a relative term, but anything over 2k rpms would create a negative vac on the can.

[Josh]

Dont you need vacuum, for the catch can to work properly?

there is vacuum inside of your crank case........

[jr_ss]

there is vacuum inside of your crank case........


Wrong. You have positive pressure in your crankcase, hence the factory catch cans... Pull your oil fill cap and tell me your hand gets sucked in and I'll call you a liar. Healthy engines have minimal to no air coming out, as engines age it increases over time.
Pulling a vacuum in your crankcase helps seal rings to the cyl walls and remove oily air from it. There are so many ways to argue this though. However YOU want to run it will be fine if YOU'RE happy.

[EsChassisLove]

Wrong. You have positive pressure in your crankcase, hence the factory catch cans... Pull your oil fill cap and tell me your hand gets sucked in and I'll call you a liar. Healthy engines have minimal to no air coming out, as engines age it increases over time.
Pulling a vacuum in your crankcase helps seal rings to the cyl walls and remove oily air from it. There are so many ways to argue this though. However YOU want to run it will be fine if YOU'RE happy.

This.

I found my SR running so much smoother with the vacuum completed and hooked up correctly.

It comes from the factory like that for a reason. I run 2 catch cans, the oem and an aftermarket can. No problems, or oil at all.

[wileymotorsports]

Steel wool, will effectively trap airborn oil vapor... The only problem with routing back to the intake side of the turbo, is the chance of lowering your actual octane rating with the oil in the air. A sealed catch can with a vacuum on it and the crankcase will net high power numbers than a vented to atmosphere can will.

You can get a check valve and Venturi for the exhaust setup through summitracing. I'm actually going that route on my VVL conversion. The venturi will pull the vacuum you need once the turbo is spooled. Spooled is a relative term, but anything over 2k rpms would create a negative vac on the can.


Thats exactly what I want do to with my car do you have the link from summit racing so I get the right parts. I feel more comfortable running the line to the exhaust, especially if Im gonna put steel whole in the catch can. That way no risk of turbo damage or oil soaked air getting back into the engine.

[codyace]

It comes from the factory like tha for a reason. I run 2 catch cans, the oem and an aftermarket can. No problems, or oil at all.

100% agree, and that's how I run my car as well. Not a drop of oil anywhere.

[lazysk8er2]

This.

I found my SR running so much smoother with the vacuum completed and hooked up correctly.

It comes from the factory like that for a reason. I run 2 catch cans, the oem and an aftermarket can. No problems, or oil at all.

got any pics?

[wileymotorsports]

Pictures of that setup would be great!

[jr_ss]

Wiley, here are the links to the items needed to route it to the exhaust...

Venturi nipple
Moroso 97810 - Moroso Replacement Weld-In Nipple Fittings - Overview - SummitRacing.com (http://www.summitracing.com/parts/MOR-97810/)

Check valve
Moroso 97800 - Moroso Replacement Check Valves - Overview - SummitRacing.com (http://www.summitracing.com/parts/MOR-97800/)

[codyace]

got any pics?

Rear block vent, to the OEM Oil Air Sperator in the back behind the wastegate, to the VC T, from the VC T to the Greddy catch can, from the catch can to the intake. PCV hooked up on far side like OEM too. Don't mind the two different catch can hoses they are now the same (man that is an old pic haha)


http://www.codyace.com/albums/album303/bay_35.sized.jpg

[wileymotorsports]

Wiley, here are the links to the items needed to route it to the exhaust...

Venturi nipple
Moroso 97810 - Moroso Replacement Weld-In Nipple Fittings - Overview - SummitRacing.com (http://www.summitracing.com/parts/MOR-97810/)

Check valve
Moroso 97800 - Moroso Replacement Check Valves - Overview - SummitRacing.com (http://www.summitracing.com/parts/MOR-97800/)

Thanks!!! Im going to order the parts right now. What AN size fittings and hoses are you guys using to replace the T and PCV?

[EsChassisLove]

Mine basically looks like Codyace' you just can't see the can from that angle.

[jr_ss]

Thanks!!! Im going to order the parts right now. What AN size fittings and hoses are you guys using to replace the T and PCV?

I used -10AN fittings and lines...

[wileymotorsports]

I used -10AN fittings and lines...


Ok great thanks for your help!

[4x4le]

Im going to be running something very similar to this on my new engine, except its the vibrant performance one. I wont be running a can either.

I do however have the blu 808 modified valve cover. I have found there to be no need for a can anyways with this valve cover when routed normally.

[Kingtal0n]

You have positive pressure in your crankcase, hence the factory catch cans... Pull your oil fill cap and tell me your hand gets sucked in and I'll call you a liar. Healthy engines have minimal to no air coming out, as engines age it increases over time.
Pulling a vacuum in your crankcase helps seal rings to the cyl walls and remove oily air from it. There are so many ways to argue this though.

good info here, I would like to add:

anything that leaks past the piston rings, into the crank case, is a potential combustion byproduct that should not be allowed to become part of the engine oil, which it may dilute and render less effective. Simply providing a way out (PCV) will keep the oil cleaner, longer. That is the first major benefit of PCV.

The next benefit is piston ring seal. A long time favorite for blown V8 engines is the vacuum pump- Drawing as much vacuum as possible from the crankcase may yield between 50 and 100 horsepower on a roots-blower style 700 horsepower V8 engine. The additional horsepower speaks for itself, having a vacuum in the crankcase is a benefit to power production, regardless of the arguable reasoning for it, It works.

So we have additional power, and cleaner oil. Now lets talk placement and functioning.

On an OEM SR20DET engine, if you notice, there is always a slight vacuum during idle coming from the T-shape valve on the valvecover. Thats because there is a direct connection from the crankcase to the intake manifold, that, during engine vacuum situations, pulls a vacuum from the crankcase.

But during a boost situation- that is, when power production is expected, that valve shuts off tight. Why? because if it remained open, the boost pressure in the intake manifold would ADD pressure to the crankcase, instead of pull a vacuum (we want a vacuum, not additional pressure). So where does PCV come from during boost situations? How can the engine have a vacuum in the crankcase during boost, if there is boost pressure in the intake manifold?

The only source inlet vacuum on the SR20 engine during a boost situation is: The pre-turbocharger inlet pipe. That is where and why the OEM PCV valve connects to the valvecover from the turbocharger inlet- During boost, the turbocharger is sucking air from the inlet pipe, and some of that suction is applied to the crank case!

The negative of this situation, is of course, oil vapor from the valve cover may enter the turbocharger. And indeed, some of it does. The factory has a decent baffle and catchcan designed to somewhat deal with this situation, but it may be improved upon with an additional catch can of proper design, placed between the valvecover and turbocharger inlet. This is perhaps the safest design, however, some catch cans do not provide an adequate vacuum source to be applied through them, and there is very little testing and development done this way, so choose carefully and route carefully when adding a catch can between the valvecover and turbocharger inlet.

The only "safest possible way" of keeping a PCV system during boost functioning without utilizing the turbocharger as a vacuum source is: an external vacuum pump. If you have an external pump (say, belt driven) Pulling air from the crankcase- you no longer need to worry about oil getting into the turbocharger inlet and fouling your precious plumbing.

:dead:

[EsChassisLove]

Next question is who makes the BEST catch can.

I know theres a catch can thread, but that thread seems like mainly pics of set ups.

[wileymotorsports]

I have one more question, do you guys replace the PCV with the AN fittings if I'm going to T everything or do I keep the PCV and add the AN fittings to that??

[4x4le]

There really is no reason to replace the pcv valve with an AN fitting. Also routing it to your exhaust properly will pull a vacuum on the crank case still. In all actuality running it in the exhaust is pretty much the same thing as putting it in the turbo inlet if not better. There isnt much of a vac AT ALL between your filter and turbo and if there is your filter is too restrictive. There is a small lack of pressure but it really isnt drawing as hard on your crank case as you might think.

The shape of the venturi does cause a pull on the crank case (if positioned properly). The velosity of your exhaust will create a lack of pressure in the system and pull on the crank case. Just as in your turbo inlet, there really isnt a vacuume to be measured, there really isnt positive pressure to be measured in your exhaust.

[wileymotorsports]

The Venturi holes face towards the rear of the car, correct??

[kevmeistah21]

Rear block vent, to the OEM Oil Air Sperator in the back behind the wastegate, to the VC T, from the VC T to the Greddy catch can, from the catch can to the intake. PCV hooked up on far side like OEM too.

I never thought about that, I just bypassed the oem seperator. I'm gonna put it back tomorrow
Lol! Thankss!

[cotbu]

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. I kept my separator for a while until experimenting with megan and ebay manifolds. That's when I noticed oil in my intake pipes all the way to the intercooler. After cleaning and putting everything back to stock, I notice I split the old ass hose, so I peeled it apart. That's when I found the fitting. Put that fitting in the new hose, removed the separator, and took it for a spin all good. So I left it like that for a month or so. Checked my pipes clean, no film. I eventually swapped the megan crap back on. Yeah it cracked! This Is R&D!

[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 (http://www.supramania.com/forums/showthread.php?145318-Custom-Catch-Cans-Fuel-Rails-Made-For-Needs-By-Alphi-Of-VRP)

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]

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.


http://www.google.com/imgres?q=sr20det+engine+bay&um=1&hl=en&sa=X&biw=1024&bih=630&tbm=isch&tbnid=FjqlJ6W5H50IOM:&imgrefurl=http://hardtuned.net/forums/index.php%3Fshowtopic%3D228814%26st%3D30&docid=-Qriv6fbynJ3HM&imgurl=http://www.nissansilvia.com/forums/uploads/monthly_09_2009/post-63774-12536111069456_thumb.jpg&w=400&h=300&ei=JbkLT-ujFImJiALRkoGKBA&zoom=1&iact=rc&dur=549&sig=108484731248452153589&page=7&tbnh=122&tbnw=159&start=87&ndsp=15&ved=1t:429,r:5,s:87&tx=98&ty=83

[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

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!:lfault:

[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.

http://i44.tinypic.com/j14o4x.jpg

[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

http://i300.photobucket.com/albums/nn40/4x4le/silvia/0901091557a.jpg

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]

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]

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]

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.

[4x4le]

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.

its a step in the right direction, my valve cover is like doing the 13.4 cover but I still used a can that got very little oil in in afterwords. I never ever drained it and there were just a few drops. Im not going to run a can on this next engine just because I can run shorter hoses then, just running it to the venturi in the exhaust where it can cook.

[Frank_Jaeger]

Bumping this to add that in my research a lot of evidence (i.e. people using vacuum gauges) suggests the back pressure of the exhaust under boost prevents scavenging. I'm going to be running my catch can line preturbo.

[KAT-PWR]

Anecdotally my friend who is 100% performance oriented did a slash cut and said he had adverse effects, I will ask him what he encountered.

[jr_ss]

Bumping this to add that in my research a lot of evidence (i.e. people using vacuum gauges) suggests the back pressure of the exhaust under boost prevents scavenging. I'm going to be running my catch can line preturbo.

Frank, what components were plumbed in this test? Was a Venturi utilized? If not, of course they weren't seeing any benefit. Venturi's use exhaust flow/velocity to pull the vacuum. If they did use a venturi, was the slash pointed in the correct direction?

I have not put a gauge on my exhaust line/CC to see an actual number, but I can tell you at idle I have decent vacuum on the system. I'll be glad to swing by and let you listen to the air release when the dip stick is pulled out at idle.

[Frank_Jaeger]

Frank, what components were plumbed in this test? Was a Venturi utilized? If not, of course they weren't seeing any benefit. Venturi's use exhaust flow/velocity to pull the vacuum. If they did use a venturi, was the slash pointed in the correct direction?

I have not put a gauge on my exhaust line/CC to see an actual number, but I can tell you at idle I have decent vacuum on the system. I'll be glad to swing by and let you listen to the air release when the dip stick is pulled out at idle.
Most that I've read were using the summit kit. It has an angled bung with a slash cut tube. Before this is a check valve. I can't verify if they had it oriented properly though.

I might take you up on that. I'm rebuilding my SR right now and I'm wanting to get the best seal possible as I wear in the new rings. A few years ago I read about using the exhaust to pull vacuum and it seemed like the best method however checking again now it seems that it doesn't do so well under moderate / high loads.

[jr_ss]

Just shoot me a pm if you want to meet up.

Here is the correct orientation required for vacuum. If it's positioned the opposite way, it will not function properly. This isn't new tech by any means. Drag racers have been using this for decades.

[tunermt]

whether or not this set up will work for your car GREATLY depends on the exhaust on your car and for 90% of cars it will not work as the exhaust DOES get back pressure that is not over come by the vacuum created from these.

Its not that hard to set up and test your self though so if your considering it just give it a go and T in a MAP sensor or boost gauge and report back. *you'll see + *

[jr_ss]

Yes, backpressure is present, but the exhaust velocity is what causes vacuum on the catch can. Is that back pressure enough to force closed the check valve vs the suction pressure created by the Venturi? That would be the question to ask. Is the differential pressure across the check valve/Venturi enough to create flow? Dyno numbers have proven this works, I'm not sure why there is so much skepticism.

[Grenade180sx]

The only time ive seen this done, is when blowby is high and they get tired of dumping the catch cans, its just hiding the problem with rings. A properly plumbed catch can setup doesn't involve running anything to your exhaust.

[jr_ss]

The only time ive seen this done, is when blowby is high and they get tired of dumping the catch cans, its just hiding the problem with rings. A properly plumbed catch can setup doesn't involve running anything to your exhaust.

It's no different than running in to the turbo suction, just like a factory setup...

[TheRealSy90]

You could have a catch can ran to the exhaust even lol.


Weird, I figured the orientation of that valve would have been the other way, with the opening facing down stream. Interesting.

[KAT-PWR]

The only time ive seen this done, is when blowby is high and they get tired of dumping the catch cans, its just hiding the problem with rings. A properly plumbed catch can setup doesn't involve running anything to your exhaust.

This is true, but on the ragged edge of tuning any oil vapor will decrease your effective octane rating, you won't see that happen with an exhaust ran evacuation point

[Kingtal0n]

IMO you shouldn't be on the ragged edge unless the car has sponsors, free engines, and is a serious race car. And Those cars will get vacuum pump, dry sump.

Probably need something with more resolution that a map sensor or boost gauge for PCV related activities. A gauge/sensor which renders 32"~ of H2O (WATER) on a data-logger would be ideal.

[RocketOgre]

While I do get that using some neat little effects of fluid dynamics it is conceivable that you could create a lower pressure in the exhaust line than exists in the crankcase. I do not understand why anyone would consider it for more than a split second when you have a constant source of vacuum while the engine is running at the intake. I mean maybe in a crazy all motor ITB build that doesn't always pull vaccum, but FFS just get a quality catch can with good filtration and you are done. Plumb the drain hole at the bottom into the dipstick tube, or turbo return line, and you don't even have to check/drain the thing. Not that most people on here need anything more than the factory one that came on SRs.

[godrifttoday]

I have a ka24de-t and on the stock pcv box location I simply welded a 10an fitting and ran a hose to my downpipe with a check valve. It's a moroso unit cost about 30 dollars , you must get the pipe that has a cut out , to weld it to your downpipe

[jr_ss]

While I do get that using some neat little effects of fluid dynamics it is conceivable that you could create a lower pressure in the exhaust line than exists in the crankcase. I do not understand why anyone would consider it for more than a split second when you have a constant source of vacuum while the engine is running at the intake. I mean maybe in a crazy all motor ITB build that doesn't always pull vaccum, but FFS just get a quality catch can with good filtration and you are done. Plumb the drain hole at the bottom into the dipstick tube, or turbo return line, and you don't even have to check/drain the thing. Not that most people on here need anything more than the factory one that came on SRs.

As stated above, when you're making decent power(500+ crank) on our tiny motors, maintaining octane ratings is paramount. Since that can be directly effected by oil vapor getting ingested by the motor, it is important to minimize or eliminate it entering the motor period. Regardless of ones opinion 500hp is pretty serious power from a small displacement motor. Cylinder pressures are pretty high and any error in fueling, timing or a combination of other factors can damage the motor pretty quickly. Granted, tuning to the "ragged" edge would be for one purpose, making the most power without regard to motor life. I prefer my tune conservative so I don't have to test fuel at every fill up for octane ratings to ensure I'm not going to pop my motor.

Yes, suction at the turbo is a good constant source, but not everyone has an intake pipe, let alone a filter mounted to their turbo. I plumbed mine to the exhaust because I didn't want the contaminated oil vapor sucked into the turbo and essentially puked into the intercooler, plumbing, sensors, and eventually motor. What you're sucking out of the motor is nasty shit and it will gum things up over time.

[jr_ss]

I emptied my catch can today. It hasnt been done in awhile and this was the result. Green tint/hue is from the Brad Penn motor oil I use. I'd say my exhaust evac is working just fine...

http://i627.photobucket.com/albums/tt352/jr_ss/VVL%20Conversion/4496ACF5-42B8-4CE1-8216-15D7758ECE1C_zps5ydb3pth.jpg
http://i627.photobucket.com/albums/tt352/jr_ss/VVL%20Conversion/AF38D4D0-5D67-41AB-B865-0D441538D880_zpsxdkegv7q.jpg

[Kingtal0n]

if I were running an exhaust driven PCV system without monitoring, I would incorporate a check-valve breather, such that during boost the system would default to open atmospheric (no pcv action) if there were any pressure, since I would also be using a quiet exhaust system (probably high back pressure). Back to normal driving and the exhaust driven system does the crankcase vacuum as if it were on the intake manifold, this way oil would never see the intake valves no matter what and any positive pressure that the exhaust driven setup couldn't deal with would exit via check valve (because I weren't monitoring it to know for sure). There is a guy on LS-1 tech "Mighty Mouse" promoting a similar setup, and after considering it, I agree this is a fair compromise on a high performance engine without crankcase monitoring refinement.

Oil may be collecting during normal driving, and none during WOT. Without a gauge on the crankcase, there is no way to monitor what is really happening. Also, oil vapor (as single, gas state molecules) might work its way into a tube and collect there (hydrophobic interactions) without any help from pcv systems (could be at any pressure around atmospheric).

[jr_ss]

While I'll agree that it could be from normal driving, back pressure is present while the car is running, only in varying amounts. With that said, so is exhaust velocity.