Air Oil Separator Vs. Catch Can Part 3 - So what is Blow By? The Analysis is in! 

Thanks Scott! Thanks for watching, and it is good to hear that you appreciate the direction that we are going with the channel.

Thanks for watching and glad that you found this helpful. Stay Tuned!

Thanks for that input Charlie, and thanks for watching!

Thanks for watching Bamefr, and thanks for your feedback. That is exactly the goal that we are shooting for with our videos, and it is great to hear that you are getting so much out of them. Many suspension videos are in the works, so stay tuned!

Over 300k. Very niiiice. Keep the community updated. Nasioc.com if you don't know about it.

Thanks for the comment, and that is really interesting. It seems like blowby gets worse on Subaru's the more boost you run, so very similar to your initial problem. Definitely something to keep in mind as we research and try different things. Thanks for watching and Stay Tuned!

@@FlatironsTuning appreciate it

Thanks Keith!

I have an S202 Drivetrain (matching trains, axle, and diff) in my 06 Wagon. I love the feel of that transmission. All Mechanical, All Day.

Thanks for the question. It really all comes down to how much oil, if any, you are seeing move through your PCV system. The first indicator of that is how much oil you have to add between changes. If you don't need to add any oil, then you are not moving any through the PCV system most likely. So the need for a catch can or AOS is minimal. Just keep an eye on your oil consumption and that will tell you when you need to do something. Thanks for watching and Stay Tuned!

@@FlatironsTuning Thank you for that Response brother. Subies forever.

Thanks Dagan, and thanks for watching!

Thanks Benjamin!

Thanks for watching Marco. Appreciate your support!

Thanks for watching, and thanks for your question! We actually have a 335I that we are going to be working on here shortly :-). The simple answer is that if your are going to vent to atmosphere, you have to make sure that you completely separated your PCV system from the intake because you don't want to pull in unmetered air. And usually doing so will require a tune because you are no longer pulling in spent exhaust gas that no longer has any usable O2. On the directed injected engines, keeping that oil vapor out of the inlet track is very important because it can lead to a lot of deposits as you say. We have a catch can in line for the 335, so stay tuned. Hopefully that will be one of our winter projects :-)

Thanks for watching, and glad that the video was helpful. Stay Tuned!

Thanks Andrei and thanks for watching!

Thanks Louis! If you aren't losing much if any oil, and you aren't tracking your car, then I'd say that the need for any modification of the PCV system is minimal. If you decide to start making more power, or you do notice that you are using more oil, or if you start to see more signs of oil in your intercooler, etc., then that would be the time to reconsider. Thanks for watching!

hello Flatirons, my 2016 STI (26,000 miles) is stock except for CAT back exhaust and I just got back a very good engine report from Blackstone Labs. Also I haven't noticed any oil loss, so I'm sure you would probably say AOS is not needed. However if I was to go stage 1 (Cobb SF intake and accessport ots map tune) in your opinion would you recommend getting AOS? thanks

Thanks for your question. My recommendation would be to put on the intake, and just monitor your oil usage for about 1/2 to a full oil change interval. Most likely you won't see any change, but keep an eye just to be sure.

Gotcha, so monitoring oil will be key. I was also leaning in the direction of not getting AOS, especially after reading that an AOS can potentially void warranty. Thanks for all your help. I love the channel, keep up the greate work :)

Thanks for the question Paul. You definitely don't want to seal up the PCV. That would cause some really nasty problems pretty quickly. The need for some form of crank-case ventilation comes from the fact that your rings will never seal 100%. This means that some part of the combustion gasses will get into your crank-case (can be tested with a "leak down" test), and this causes positive pressure. You need to give that pressure a way to escape, and that is where the PCV system comes in. Beyond that, the crank-case will actually go through a few different conditions as you drive, and one of the main reasons that there is a PCV valve incorporated is because you need to the PCV system to act differently when the intake manifold is in vacuum compared to when it is under positive pressure. This is something that we are exploring, and we may dive into it in detail later. For now, if you haven't all ready, I'd recommend looking at the video that we have done about the Atmospheric vs. Recirculated AOS. It starts to go down that road a bit. Here is that link: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-6bPgslpWjak.html Thanks for watching, and please feel free to reach out to us if you have any more questions!

Thanks for your question. Go through this video that we put together talking about what you can learn by monitoring crankcase pressure: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-HAvxjSdQsXI.html That would be the piece of information that you want to start looking at as it may well point you to the cause of your problem. At this stage in the game, it could be a lot of things. Once you have a sense of what is going on in your crankcase, if you still need help, let us know and we'll see what we can do! Thanks for watching and Stay Tuned!

That is a great question Bill. There are a couple of things going on related to your question. The first is that if the can/AOS is cooler than where the crank-case gas is coming from, this will encourage liquids to condense out. If you are running a catch can, this is fine, as in a lot of ways that is the goal. But when you are running an AOS that is also returning the captured liquids to the oil pan, you really don't want to dilute your oil with fuel or water. The idea behind keeping the AOS at engine temperature is that it will keep the fuel and water in their vapor state, and let them exit the tank either to the inlet or to atmosphere depending on set-up. We have actually not been running the coolant lines to our race car's AOS for a bit, and we were concerned that in doing so, the fuel and water content would go up. In that case though it turned out that the oil itself was hot enough to keep the fuel and water in their gaseous state, and there was no issue with diluting the oil. But that is a race car, and it is always running pretty hot. So there is also a big part of the necessity of the coolant going to the tank that comes down to what is done with the car. Ultimately, you just need to start by getting a good baseline of what is happening in your tank, and decide if you need to make any changes. I hope that helps and thanks for watching!

Thanks for your question Tito. We have been working on a few different projects, but this is certainly one of them :-) I am close to being done with the next video and it should be out this week, or early next week. As I say in the videos, the biggest thing to look at is how much oil you are going through. If you are having to add more oil between changes than would fit in your desired catch-can, something like an AOS with a return would be a good idea. I'd say start there, and stay tuned. More information is on its way :-) Thanks for watching!

Almost. I have a very modified bolt on challenger. I believe the edelbrock intake manifold and massive 90mm throttle body is the cause because if I goose it then turn my car right off I'll have a smokey next startup. I assume the vacuum has increased drastically from those intake mods and has more pull, pulling everything (gases and oil vapor) through the catch can. It's only happened 3 times but I need to look at a air/oil separator.

Thanks for watching Oleg. Yes, we are going to be putting on an AOS here shortly, and we'll go through that install. Our plan is to run the car in various different conditions, and then check the oil and see what we find. Stay tuned!

Thanks for your question. This is a tough one. We have had good luck with the Radium, IAG, and Killer-B AOS kits. It largely depends on how much oil you see going through your PCV system. And in some cases, a dual catch-can can be more ideal if you aren't seeing much oil going through your PCV as well. We are going to be taking a look at this here soon, so Stay Tuned!

Thanks for your question. I'd definitely recommend taking a look at what we found when we started to look at crankcase pressure. Here is a link to that video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-HAvxjSdQsXI.html

@@FlatironsTuning thanks. Watched the vid after I asked my question. Very interesting findings. Great info.

Thanks for your question. I'm not sure what you mean by the oil in the pan. If you can give me a little more detail on the question, I'll do my best to answer. Thanks for watching and Stay Tuned!

Thanks for your question. It does seem to help. You just have to make sure that you are using a large enough fiber that it won't come apart. Thanks for watching and Stay Tuned!

Thanks Isaiah! Stay tuned, more are on the way!

Thanks for your question. I would not say that would be normal under most circumstances. The best place to start would be to go back and check the routing of all of your hoses, and double or triple check that everything is connected correctly. Is the car modified? If so, ho far have you gone? Bigger turbo, etc.? And what kind of use does the car see? Is it a track car or a daily driver, etc.? Lastly, were you seeing oil consumption before you installed the AOS? With some more information, we'll do our best to help out!

Did you get a tune for your comp series? Need one if you’re running one

Thanks for the question. The reason that keeping the can at coolant temperature is significant is in order to allow the fuel and water that are trapped in addition to the oil to evaporate and leave the oil before it returns to the pan. If the liquid is allowed to cool, then the fuel and water that is captured would get returned to the pan in addition to the oil, and over time, that could significantly increase the percentage of those fluids in your oil. Hope that helps, and thanks for watching!

oh okay so adding the coolant helps keep the can "hot" with respect to the liquid rather than the air? thats interesting. thank you!

I’m assuming they use water coolant after it’s heated by the motor, so that it passes through the separator heats the condensed water and fuel -they pass through to the cylinders and are burned off, while the coolant then cycles through to the radiator, and the a/o separator is left with heavy particles and contaminants.. would be my guess.

That is correct. The AOS taps into the cooling system, and uses engine coolant to increase its temperature.

He mentioned that in video #1, but since ventilation into the atmosphere is probably illegal the PCV systems were made.

Just eliminate your pcv system altogether, if you run big boost and are constantly hitting big revs. It restricts the amount of blowby that you can evacuate - You'll know to do this after you blow out oil seals!

Thanks for your question Brian. We haven't installed one yet, but as soon as we do, we'll post up the results.

Thanks for your question. To an extent, yes. To a certain extent, this is what the PCV system is designed to handle. Hope that helps, and Stay Tuned!

Yep, fuel vapor and water vapor. Thanks for watching and Stay Tuned!

@@FlatironsTuning I had the same thoughts of re-routing it back to the oil pan. I'm so glad I didn't. Several years ago I accidentally filled my freshly rebuilt transmission with a couple of gallons of water. Someone had repurposed some empty jugs of transmission fluid and had sat them down by my transmission fluid. I didn't notice until I was checking the level and the dipstick came out bright pink. Took me forever to get that flushed out.