Who makes a good AOS for our cars?
 

Trying to decide between catch cans or AOS.

Who makes a good one?

D

Radium.

- AdrianG

crawford if you want an actual AOS and to dump it back into your block. I personally like VTA which you cant really screw up. I use FullBlown's but they are all pretty much a can and some hoses.

Crawford is the only company that makes an AOS closed loop system as far as I know.

I have a Radium Engineering dual catch can system. One can for PCV and one for crankcase ventilation. It works great.

I'm not a fan of the AOS. The stuff coming from the PCV isn't too bad. But the blow-by gasses coming from the crankcase ventilation are essentially unburnt fuel and exhaust gunk that goes back in to the crankcase. Pair that with condensation when the car is sitting, and you'll have some water droplets going in the crankcase too. The AOS 'cleans' the air coming in to the intake system but it still pushes whatever's been removed from the air back in to the crankcase. Not only that, having a catch can could predict issues with the engine, I.E. you're having a ridiculous amount of blow-by gas residue in your can or something.

If you don't like draining the oil, go for the AOS. If you don't mind, go catch cans.

I was checking out the radium as well...

How quickly will the cans fill up?

Will it last a 20 min race?

If it doesn't you have bigger problems. Mine usually gets emptied every 3000km but it's always less than a 1/4 full.



- AdrianG

I have a radium pcv can and emptied it after 4k miles, including a track day and it was about 1/3 full. Still had some room.

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I have the Raduim, It's perfect.

Grimmspeed makes one. Unsure if it would fit though. Replaces oil cap, but there's a bunch of stuff surrounding our oil cap in the engine bay. Worked great on my EG33 Impreza.

http://www.grimmspeed.com/air-oil-se...x-sti-lgt-fxt/

I have Radium dual cans as well. So far no oil detected after a few thousand miles with one autox day.

I can get one person a good deal on a new dual can kit at less than their site ($30 less) with free shipping to the US if a lucky person is interested.

Really, you didn't have any after the autocross day? I had about 2 teaspoons of oil in my PCV catch can.

I looked and I have nothing on my dip stick. As far as I know they are installed correctly but perhaps the hoses are on backwards as there weren't any install directions for the supercharger kit. All I had to go from was someone else's install they posted.

I use one of the Mishimoto cans, works perfectly for me - I'm actually going to clean it out to see how much oil is in the can, I'm thinking about a cup or so

I have used the Crawford AOS on every one of my subaru's since 2007 including my BRZ now. They have all performed flawlessly