I was thinking about AOS because every video on RU-vid recommends it religiously. Like the video said, stock car, impacts of an AOS minimal. Thank you for the video, really honest advice.. love your channel and also listen to podcast 😊👍🏽
Agreed. I have stock 2016 STI and my throttle body, intercooler, etc were very clean of any oil buildup so this video clears a lot of questions up. I think I will go with a small catch can instead of that massive AOS. Awesome!
If anyone is tuning a GM ecotec motor, don't remove the stock AOS baffle system that is built into the valve cover. I thought I was smart by welding on a bung to help reduce crankcase pressure so had to drill out the plates and remove the plastic baffles. Eventually had to double up with 2 custom AOS to control the oil coming out of this motor, a small inline one at the valve cover installed so it could drain back, and a large swirl pot AOS I copied from designs I found.
This is great information! When we cracked a Ringland in our WRX rally car, even with the AOS we still were pouring in like a full 6 quarts of oil every 10 miles. Perfect example of the engine being so damaged that the blow by is overwhelming the AOS. I’ve also personally found kinked hoses on other cars, which usually ends up making a mess too as the blocked hose leaks oil everywhere.
I’ve wondered about plumbing an electronically controlled vacuum pump into a VTA AOS setup for hard driving operation. This could be much more cost effective and help eliminate a substantive amount of positive pressure in theory. In addition, you nailed the AOS revelation! They provide aid to the consequences of an underlying problem. Pop the oil cap on a healthy running EJ at idle and those who don’t know, would think it has a big problem at normal operation.
Crankcase pressure issue can be greatly reduced or even completely solved by connecting AOS exit to electric pump that starts to work when boost hits. Compared to dry sump it's much cheaper and also do not require extremely frequent oil changes. So I think it's best solution to highly tuned street car.
@@lowcountryfungi I'm using Subaru secondary air pump. Used one, very cheap. Inlet connected to AOS and outlet connected to atmosphere. It required plastic welding to connect hose to inlet, but you can use any other secondary air pump that already have two hose connections. I'm also installed MAP sensor from atmosphere Subaru to measure crankcase pressure. With pump working it's reduced from 1.15 Bar to 1.03 Bar (1.00 is atmospheric pressure), and BHP increased from 680-685 to 700.
Great video. My experience is very positive with the IAG AOS. No oil usage, oil is clean at 2500 miles, and no oil in intake (competition series vented but recently plumbed into the exhaust for venturi effect to create some vacuum to evacuate crankcase). This is on an 06 with IAG block, FP green turbo on almost 30psi, and supporting ethanol fuel system.
Boxers are hell for oil. I tried to turbo an EA82 for fun. The thing that finally made me give up was that once I went beyond like 7psi of boost, I couldn't keep oil in it. The SPFI EA82 doesn't have the built in AOS like an EJ, and so there's not any good place to get PCV from, leaving only the valve covers. I could only return it to inlet. As soon as I put it in a catch can it'd just puke oil, and eventually the engine just developed leaks everywhere. I have an EJ255 in that car now with a stock PCV system on low boost and it's working very very well. No issues, just turn key drive. The next steps are turning it up as is, and then eventually fix the rust, cage, slicks, and dry sump. There's an Aviad kit that uses the stock oil pump with a scavenge pump in place of the AC, bring your own tank that only costs 2k$. Either that or I've considered doing used NASCAR parts.
Hi. Any thoughts on Verus Engineering’s AOS systems for the GR Supra & GR86? Their systems have a “maintenance-free” drain-back kit (& coolant add-on for the 86).
Thanks for watching and thanks for the question. We haven't had one in hand or on a car to test yet. I do like their design, as it should be very effective at filtering the oil and liquids out of the PCV gasses. As long as it drains back efficiently, it looks like a good design. I do want to give it a try at some point. Hope that helps and Stay Tuned!
so I have a 22 wrx with radium dual catch cans that have been installed over 10k miles, and there is always only a little bit of the oil on the bottom of the cans. I never needed to empty them since the installation. When I installed the aftermarket charge pipe I still found some amount of dark black oil on the turbo side, but the throttle is pretty clean. I'm stuck in a cycle. Because on the one hand no oil is the best, it proves that the engine is working healthy, and I hardly lose any oil per oil change cycle. But when I saw that the catch can didn't have much oil, but there was oil in the charge pipe, I was worried that the catch can wasn't working. I asked some questions about it on the forum, and more or less the same model of car will have a good amount of oil in it after couple thousands miles.
Y'all have hinted at having a product in the works related to crankcase pressure, is that still happening? Any hint on an ETA? Thank and keep up the great work.
The main contributor to my track/street car selection was having a factory dry sump to deal with lateral G. Secondary was to deal with the crankcase pressure for me. Regarding Subaru the plumbing on our IAG ended up getting pinched, clogged and causing breather to stop breathing. I'm redoing it with the 3MI hose and hoping to get the crankcase pressure closer to normal. In my Honda I run a breather with giant AN lines to the valve cover and a large AN line to drainback to crankcase. I'm interested to see someone have larger breather openings on the Subaru valve covers and have vented breather/s.
I have an ej25 daily driver making 380whp on e85. Sway bars and mild summer tires. IAG AOS. Sometimes when I start it after sitting for a few hours it smokes out the tail pipe for a minute or two then clears up. Fresh heads, fresh block. Is this an AOS drain hose issue?
Thanks for watching and thanks for your question. I'd recommend checking all your plumbing on the AOS. If any of the hoses are pinched, blocked, etc., address that first. What this can be is a sign that your crankcase pressure is building and preventing your turbo from draining. Especially with E85, check to make sure that none of your hoses have any of the waxy buildup that can result from that fuel and block them up. Hope that helps and Stay Tuned!
Question, i have a bit oil in my TMIC in the hose that connects turbo. My question is, I know it’s not bad I guess. What can I do to to minimise this, i have a stock ej25 sti 2013. You have said that most cases aos is not a fix rather a bandage. Should i just replace my pcbs ?
Thanks for watching and thanks for your question. That small amount of oil is basically normal. If you aren't having to add much if any oil between changes, that will give you a good idea how much oil is moving through your PCV system. If it is a very small amount, that is where a Catch Can would make sense (you really want to use 2 ideally, one of each circuit). If you are moving more than about 1/2 quart or more between changes, it would likely be best to use an AOS like the IAG or Killer-B. Hope that helps and Stay Tuned!
Great info here. Thank you for sharing. Sounds like someone needs to design a proper oil catch can system for the daily streetcar. That will help actually with the extra crank case pressure. ASO is nice. But very overpriced I feel. And not really needed for the everyday car.
So no solutions for the foreseeable future? I’m running an IAG street AOS and IAG comp pan w/ pick up tube. I haven’t seen any oiling issues so far but would like to know for the future. Why does it seem like the Japanese and UK STIs seem to be more reliable?
Thanks for your question. I'd say that you are in good shape then, just keep an eye on things. Hopefully in the next year or two, another, better solution might come up. Thanks for watching and Stay Tuned!
On a stock 2018 etc should I be running a dual catch can setup? Or should I just run the pcv side? I’m looking at the Mishimoto catch cans and it looks like for 2018 to 2021 they only have the pcv side catch can setup.
Thanks for watching and thanks for the question. If you are going to put a catch can on your car, you really need 2, one for each PCV circuit. Hope that helps and Stay Tuned!
Great video! Do you have a video on what best routing would be for a catch can on an ej? I bought a cheap one. I was planning to buy some good quality hoses before i install. Thanks for the good content!
Thanks for watching and thanks for your question. Take a look at the PCV video first: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-mO9mxDUDUDc.htmlsi=VLToXygz6gX3RoWI Then this one talking about putting on a dual catch can. Yes, you need 2. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-iJs1SSAOYiU.htmlsi=Ik0Llkj_rCX3_hRL Hope that helps and Stay Tuned!
Jon, really great content as always. Breaking paradigms and enpirically not worried to contradict general and wrong beliefs. Regading catch cans, are there better ready-to-go solutions than Radium dual catch cans system, which tou said it is not great? Can you tell a bit more about what are Radium catch cans system cons?
Thanks for watching and thanks for the question. First off, I discuss the Radium catch cans here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-iJs1SSAOYiU.htmlsi=xqUru3Itn4h5AYaL They are a little small which isn't the end of the world, but their routing is not good. If you change it as I did, it seems to work well, but for track use they can be too small. Hope that helps and Stay Tuned!
Is an aos a bad thing to have supposing you don’t have an underlying problem of any type? Is it good to have on a healthy engine? Or does it just add extra complications that don’t do anything worthwhile?
Thanks for your question. I would say that if you have a car that is running well, and not using any oil between changes, I would only look at a dual catch-can setup if anything. Adding in the AOS when you don't need it brings in an extra level of complexity, and over time, can potentially start to cause issues as discussed in the video. A good dual catch-can set-up would be a simpler solution, and would be more than enough to keep any oil out of the intake path. Hope that helps and Stay Tuned!
Thanks for your question. From what I have seen, the Night Motor Sports valve covers have the same system as the factory valve covers. I don't think that their valve covers would chance the movement of oil from the valve covers any more than the OEM ones. You can see the factory covers in our PCV video here for reference: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-mO9mxDUDUDc.htmlsi=WPApETagRJHWYFEE Thanks for watching and Stay Tuned!
Thanks for watching and thanks for your question. I would say that would be a very good place to start. Dual Catch-Cans are what you really want, and as long as you aren't seeing an excess of oil moving through your PCV currently, I'd say this is a solid option. Thanks again and Stay Tuned!
Really interesting. I have a 400hp street sti that I track quite a bit with a built bottom end. I’m constantly overflowing the comp aos at the track but the engine passes leak down and compression tests. Would you say that lateral g’s and time spent at wot could be a reason as to why the aos is filling up? I’ve been trying to solve this issue for a while now. Thanks
Your block was probably built with large tolerances that is causing a lot of blow-by. If you haven’t, route the comp AOS to a catch can and see how much it is actually putting out
@@halkaracing4632I do have it routed to a 1qt catch can which it overflows. As for engine tolerances, I’m the builder of it, first engine I’ve ever built, so that probably has a lot to do with it lmao. Gapped the top and bottoms ring to .0025” which where manley pistons specs.
Thanks for watching and thanks for asking. The most likely issue is first the drain for the AOS. Take a look at the 3MI AOS drain hose first if you aren't using this yet: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-vkn7k2yMO2w.htmlsi=Oumj6L8O17IqoZTE Beyond that, there is a point where even the Comp AOS is not sufficient as discussed in this video. If your AOS is draining properly, and you don't have any plumbing issues, etc., that would be the point where you would want to look at moving to a dry-sump, as that is the solution for your issue at that point. Hope that helps and Stay Tuned!
I would agree that you should check your drain from the AOS. Remember it needs to flow downhill from the AOS back to the engine. You might consider adding a drain port to the sump or using the 3MI drain hose as suggested. Pulling lateral gees can definitely cause more oil to flow through the valve cover breathers into the AOS as well. The valve covers are baffled but oil definitely sloshes around inside our motors under racing conditions. I would also suggest you monitor your oil temps on track and make sure you’re not heating it up too much.
If someone relocated their battery to the trunk they could fit a good size oil tank there so no need for putting it in the cabin. Knowing this, and cost aside, what other disadvantages could you think of if someone was considering to put a dry sump in a mostly street driven car that gets track use a few times a year. Car makes 500 hp with 275 200 tw tires and some aero.
I think oil change cost will increase and maybe the car will take longer to get up to operating temperature before you could drive it hard. Those seem tolerable, therefore….there is no real disadvantage for a heavily modified street track toy. Thoughts ?
Thanks for watching and thanks for the question. If you had the tank in the engine bay, and you were confident in the reliable routing of your oil lines, then I'd say that the main disadvantages would be the cost of oil changes with the Dry Sump. I would also say that I wouldn't want to run the car in very cold weather or snow, just to make sure you didn't run into any issues related to cold temps. We have been on track with our car when it was 95* out so heat isn't a problem. That is all that comes to mind currently. Hope that helps and Stay Tuned!
Enjoying the content and happy to hit the like button, after all, it’s my revenge against the adds! I’m running a VF34 with standard pcv on a built hybrid by tegsport. No oiling issues for the 32k it’s run thus far. If I wanted to raise the power to 400hp (UK) would this necessitate an AOS?
Thanks for watching and thanks for your comment. Basically, when you make the change to 400 whp, that is the time to re-evaluate your PCV system and decide which option would be best. Hope that helps and Stay Tuned!
@flatironstuning So, Does nightmotorsports billet valve cover with built AOS mitigates the issue? that was the only product that was not showcased here.
Hey man. We’ve actually seen a set of these at the machine shop. Frankly they don’t appear to offer any real improvement over the stock valve covers, which themselves already have a built in AOS! The one and only advantage of the nightmotorsports covers is that their baffles can be opened for cleaning. On high mileage turbo cars, it’s not uncommon to see the valve cover baffles clogged up with oil deposits and carbon. And on the stock ones, there’s no way to remove the baffles to clean them but at that point you might as well just buy new ones anyway. You’ll still save a lot of money compared to the nightmotorsports covers.
Thanks for your question. Since the stock valve covers also have similar baffling built in, I'm not sure how much of a difference, if any, the Night Motorsports covers would make. Here is a discussion of that in our PCV system video cued up to that point: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-mO9mxDUDUDc.htmlsi=PjPGCy8LawB0JnUh&t=123 Hope that helps and Stay Tuned!
I had the stock pcv system on my wrx for 110k miles with some blowby but not allot. I finally had an iag street aos installed and over time i had multiple hoses kink and need to be rerouted and my engine just failed at 123k miles. Im getting it rebuilt so i will know for sure soon but i think the aos played a major role in my engine failing, which is ironic considering how much its marketed as a solution.
they system it self is great on paper , but the problem would come from hose routing and as you stated yourself hose getting pinched or kinked will definitely cause problems.
Personally, my philosophy is that if you are on a stock motor in stock power level, you do not need an AOS. The factory PCV system on the EJ25 turbo cars is very good, with baffling and built in AOS devices at multiple points in the system. Stock Subarus need to have a pretty good AOS system because otherwise they would have trouble passing the US’s strict emissions standards if they burned oil as a matter of course. However overtime it is necessary to maintain the factory PCV system. Replace rotted hoses and clogged PCV valves. Frequent oil changes will also help prevent the system from getting clogged with deposits and carbon. I have had my hands in a lot of Subaru engine bays and I have yet to personally come across a car that was burning oil due to no fault of the owner. Most frequently, I would see owners continue driving cars that have other issues such as vacuum leaks or a bad turbo and that result in other engine damage.
Thanks for your question. No Dry Sump for the FA24 yet, but it does sound like a good solution for the oil starvation issue is getting close. Check out @900brz 's latest video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Pvgg7dl-I5I.htmlsi=Qyzelrlz0B8_xWp7 Thanks for watching and Stay Tuned!
@@FlatironsTuning Thanks, I already do the short shifting around 6800 and half quart overfill, the baffles dont seem to be working. I dont trust the accumulators Misha Charoudin blew his and he was using one : ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-tFQaQuWwvbU.htmlsi=qkO2YZAsmTu6TUZF , he did say he left the car idle for a long time maybe it had something to do with that and the accusump, after living with this car for over 2 years I find it doesnt seem to like idling its bugging sometimes, and it idles to low in my opinion wich leads to poor oil flow.. I will definitly wait for a drysump cause I think its the only real solution, maybe not best for street use but im going for a fully caged drift build for track only.
Thanks for the question. Here is a link to that video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-vkn7k2yMO2w.htmlsi=CvA-NgaFXj-hNOar It is also linked in the video description. Thanks for watching and Stay Tuned!
Any opinions on the Perrin AOS? I've had one for 5-7 years. I mostly street the car with a few autocross events a year. It definitely hasn't consumed oil since I installed it.
Thanks for your question. We take a look at the Perrin AOS with other popular AOS kits like IAG and Radium here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-OjoA2qXujMA.htmlsi=Jd42vM0R3TmHB6Hu There are some better options out there for sure. Hope that helps and Stay Tuned!
I’ve had one for 2 years and it’s been great for my FA. I do have to check it once a year to make sure it’s not clogged but I haven’t found it to be yet. Just do regular oil changes and you’ll be solid
Thanks for watching. Yes, that is definitely a challenge. RCM or someone else may come out with something at some point but having that pulley right in the center would make EL headers hard to design for sure. Stay Tuned!
Thanks for your question. There isn't one available currently, but it does look like some progress is being made with the oil starvation issue. Check out @900BRZ 's latest video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Pvgg7dl-I5I.htmlsi=Qyzelrlz0B8_xWp7
Great question. We go into detail about that here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-evSn23dD38U.htmlsi=ASwfSQsLukqiXPrH Thanks for watching and Stay Tuned!
@@FlatironsTuning So the fill tank is venting to the OE AOS? But wouldn't that just reintroduce that air back into the crankcase? I did just watch your PCV video, but it might be my fundamental misunderstanding of the system.
@@byIncarnate The short answer is connecting the Oil Tank to the crankcase helps to establish a pressure balance between the tank and the crankcase. From our experience that balance is very important.
@@FlatironsTuning are all four ports on the valve covers capped off at this point? Or does the pressure introduced by blow by end up passing through the OE PCV port, into the case, into the equalization tube between the heads, and then out the valve cover ports into the intake track?
Thanks for your question. the Killer-B AOS works very well, but it doesn't work as well on cars that are moving more oil through the PCV system. As long as you aren't moving a lot of oil through the PCV, the Killer-B AOS works very well. Here is out initial testing with it: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-vGQfeqgi1XE.htmlsi=fAKjHcfier01aZfK Thanks for watching and Stay Tuned!
While I do agree that an aos is a "bandaid" for excess crank case pressure, I don't see how it's viable to sell everyone a 13k dollar engine to really fix the issue. Also my drag car that makes 44 pounds of boost has one singular aos on it, no catch can after, no bullshit and I've never seen a single drop of anything out of the aos drain. With a properly built engine they do their job perfectly. Even on higher power applications.
Thanks for watching and thanks for the comment. Glad to hear that you have found a solution that works for your application. When properly installed and properly maintained an AOS is a good fit for a number of applications. Stay Tuned!
Thank you for this video. This is why I don't buy an AOS because it has been heavily marketed as a solution, when in fact it is just a band aid and a money grabber for companies like IAG to profit on. What the community really needs is a dry sump kit that can be easily followed for installation purposes, rather than these ridiculous AOS that just takes money from Subaru community and does nothing. Honestly I think companies like IAG will just make these solutions that do nothing, so that the customer will come back with failed engine, and continue donating money to the company. If there is an actual fix, like a dry sump kit, how can these companies actually profit? These companies have done a great job with ridiculous marketing for money grabbing purposes, so ppl can come back with failed engines, and profit even more by buying their blocks that will fail even sooner than an OEM block. We need more videos like this to shed truth, dispel myths, and combat the mass marketing that makes these companies profit without an actual solution. Thanks for the video!
Thanks for watching and thanks for the comment. At a minimum, there are currently places for both a good catch-can set-up, and a good AOS depending on the application. Hopefully this will help folks pick the right one for their application, and also help to develop better options in the future. Stay Tuned!
Great, just gloss over why a catch can won't work as opposed to shelling out $400 for an iag aos (street version) which just get oil all over your intake tract and bring that nasty sludge right back into your crankcase. How about you explain the pro's and cons of an aos vs catch can. I personally have run both; iag street version aos is garbage. Every time I pull out intercooler, there's oil in there. That was not the case with a proper dual catch can setup. If going aos route; stick to the competition version.
Rotella is NOT a good oil for Subarus. It is designed to run in diesel engines which means it doesn’t have properties to make it stable at higher RPMs of a gasoline engine. It is much more likely to have cavitation in the oil pump and effectively thin out. My experience maintaining turbo Subarus is that stretching your oil changes too far will cause a significant increase in consumption. Fuel and heat degrades the oil and makes it pass through the rings and push out the breathers through the PCV. I always recommend 3000 mile changes for daily driven turbo Subarus. As well as doing changes after any kind of track event, or other scenario where you’re doing a lot of very hard driving and heating up the oil over 220F. In our racecar, we just completed a two day rally of 120 stage miles and changed the oil twice in that time.
Not at all. If you need a catch-can or AOS, just use a good design and make sure it is installed properly. Then just keep an eye on it. For a majority of cars out there, that is enough. But if you have that solution in place and you still have the issues discussed in the video, that is where further measures would be needed. Thanks for watching and Stay Tuned!
@@sohchx Did you have a lot of blow by and inconsistent oil pressure before the AOS ? no ? you wasted money yes - did the aos fix it ? yes -> not waste of money, no -> waste of money
It can be depending on the application. If you have overloaded your PCV system: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-pXQdgxHWFwk.htmlsi=hmWA5rTs5OvEOYFe Then you would want to look at either a good Dual Catch-Can setup or an AOS. If you install the AOS, make sure you use a good one (Killer-B or IAG), and that it is installed properly, ideally with a 3MI drain hose. Then keep an eye out for the trouble signs discussed in this video. For the majority of cars, that will be enough. But if it isn't that is where another solution would be best. Hope that helps and Stay Tuned!
Lol, “take wind out of the myth that Subarus are unreliable” if you need a dry sump and a built engine to run relatively low power levels on track that is definitely an unreliable engine. I love my sti, but they are just not a reliable platform on track (and off track honestly).
I run a stock S209 on track for 2 years now, previously owned a 2015 STI for 2 years tracking as well. My thoughts are as long as you run in the power range between 300-400 whp, and be mindful of lateral G by picking correct wheel/tire/suspension setup, the car can be a reliable track car. You sacrifice pace, but ensure reliability in stock form. The issue is most people want too much power, go too wide on tires, and have spun bearings left and right due to not being mindful about these issues.
@@TheLastS209 I spun a bearing on a low G track with 235 tires and 280whp, I don’t think they are reliable on track once you hit a certain degree of speed. Countless people have blown their stock blocks with minimal tire and minimal power
I mean id say Porsche engine are reliable and those have dry sump systems , its just what the manufacturer does with the engines to make them cheap to sell. But stock engines making making multiple 1000 hp runs but hey idk
