Troubleshooting Why your AOS doesn't work

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.

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.

I was thinking about AOS because every video on YouTube 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 😊👍🏽

Great sound and content (as always), thx FT ❤

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.

I have been running a catch can to an air injection valve in the exhaust quite successfully. Street car, 400whp driven hard on mountain backroads.

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.

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.

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.

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!

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 had a blocked drain hose with IAG on my 08STI 190K OG miles and I kept getting oil in my turbo inlet and Intercooler , one of your previous videos helped by giving me the info on what was happening , after I raised the AOS & the drain hose the oil was pretty much gone. Thanks for sharing

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?

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?

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.

Might be nice to have a link to go with that bit about the 3MI drain hose video 😅

@motoiq Mr mike kojima, if you are reading this, any thoughts on this information?

What's your opinion of the NMS EJ25 Oil Control Valve Cover Kit? How much do you think it helps with separating oil?

My only issue with Dry Sumps is the fact there is no ELH setup to fit around that pulley.