Anyone Running an Air-Oil Separator
 

Hi guys,

I just picked up a 2009 MS3 GT with under 12k miles. I've read around about the MZR and many other direct injection engines having issues with blow by, oil in the intake, and ultimately carbon buildup on the intake valves.

I started off thinking that I would just buy one of these oil catch can kits, but then I got to thinking about the maintenance and hassle involved in inspecting/draining it periodically, and how the climate will affect the fill rate. (More water condensation in the colder months, and the possibility of it freezing.)

Keeping this in mind, I then started checking around on the other forums and found Crawford's air-oil separator for the WRX/STi. This seems like a good compromise as it should separate oil from the air, hopefully allow moisture to recirculate through the intake, and recirculate the oil back to the crank case. Sounds great to me. Less oil consumption, no draining of the can required, etc.

The only "problem" is that to the best of my knowledge, no one makes an air-oil separator for our cars as a kit. Crawford sells a universal AOS, Ixiz sells their version of an AOS (except it looks like they don't have a clue how to spell, the website isn't especially professional looking, etc), and Grimmspeed claims that they're still in the development stage for one for our car. (For reference they do sell this for the Subaru engines.)

Is anyone here familiar with someone who has installed and documented their experience with an AOS on the MZR DISI 2.3? Thoughts? Product suggestions? Etc.

Edit: Just to compile more information, here's a thread from 2008 discussing the Ixiz AOS: New Alternatives to OCC's being adapted for MS3!

i dont think anyone runs them on this platform. most run single or dual cc setups. matt damon makes a kit on here for a great price.

the biggest downside to a aos is that they dont hold much. i empty my can weekly in the winter or about every 300 miles.

not much of a hassle turning a screw and letting it drain for a few minutes. I do it every few weeks or so.

I see no problems with a properly installed Oil Catch Can. Draining it doesnt have to be a hassle if mounted correctly. Theres a good number of options for them. Im currently testing a prototype that seems to be working great (Collected about 4 ounces in 300 miles, cold wet weather).

I already mentioned Matt Damon's kit in my original post.

As for your second comment, that doesn't make any sense. The AOS recirculates the oil it collects back to the crank case. It does not collect oil into a container to be drained later.

As for the ease of draining an OCC, that's not the point of discussion. I don't want that added maintenance, and I don't want to have to worry about my OCC freezing in the winter. The point of discussion is if there's any documentation on running an AOS on the MZR 2.3 DISI.

speedie6 has the crawford one on his ms6

isnt grimmspeed developing one of these for us? searcht the forums im almost sure it was brought up at some point.

I think you are right. Cobb put one on when they were building up his car, said it was common with subies they do. I am actually curious how this is working for him. I hope he chimes in.

Yes. There was a thread on this forum posted back in July 2010 where a Grimmspeed rep mentioned they were developing these.

In my OP I mentioned this. I also shot Grimmspeed an email to check on their progress/availability. Here's what they told me:


I'd like to hear his results, and how he installed it. Hopefully, he'll see this thread.

ok for sure. sorry didnt see that

Could someone shoot Speedie6 a PM and ask him to check out this thread? I don't have a high enough post count to send PMs. :(

The crawford is a good unit. Mann-hummel makes the provent which I think is a better one.

I was the one who trashed the idea of a grimmspeed seperator on this engine because our oil fill cap is in a direct line with the timing chain and there is no way it is going to gravity drain with oil shooting straight into it. On the subby engine, the cap is not in a direct line with anything that throws oil around.

Interesting, I wonder if Grimmspeed has considered this for whatever they're developing for the MZR.

Have you seen any documentation specific to installing the Crawford AOS on our engine? I'm curious where the oil return line is routed to, if they delete the PCV, etc.

wrong.
Most do collect the oil and have drain valves. Even the cheap ones used for air compressors.
An AOS has a fine brass mesh filter that traps the oil particles in the air circulating through it. When the particles on the screen accumulate and get big enough they form into droplets which fall down into the container. An AOS isn't a lot different than an OCC as long as the OCC has a baffle. An OCC without a baffle is pretty useless.

Uhuh. An AOS with a drain valve is an OCC. Of course it has baffles or mesh-- otherwise how do you intend to separate the atomized oil from the air flow? The difference being that one condenses and returns the oil to the crank case, and the other condenses and collects oil, water vapor, etc. which must be periodically drained.

Now, it has been noted in several threads, mostly on Subaru forums, that the AOS still may have freezing issues depending on climate. Crawford's most recent AOS has an additional inlet/outlet that they run engine coolant through to heat up the ambient temperature in the canister. People have suggested that this might also help water and fuel vapor to be returned to the intake, but I can't verify those claims. If that were the case, our cars might run even richer. ;) While interesting, I'm not sure if the idea of adding additional coolant lines to my engine bay is really desirable. This sounds like another place for something to fail/introduce air leaks/or spew coolant over the engine bay. And the idea here is to attempt to improve reliability/reduce longterm maintenance while minimizing additional complexity.

Crawford answers the 10 most common questions about Air-Oil Separators: (Note that one or two of these questions are Impreza specific)
Air oil Separators 101:

I brought this up originally awhile ago and contacted Grimmspeed. I also followed up on it earlier this year and they said they only have one engineer and haven't forgotten about us..
It has went no where since then and I ended up just getting a catch can...
let me find my thread...

here it is
http://www.mazdaspeedforums.org/foru...parator-62368/

Yeah I told the Grimmspeed guys about it.

I dont know that there is any documentation for installing it on our cars.

I don't mind a catch can collecting the oil rather than trying to put it back in the engine..

I check the oil once a week and drain the tank once a month..

I understand the logic behind it, but unless you have one of the more expensive OCCs like the E90 BMW and VW guys run, checking the level isn't an option with Matt Damon's OCC kit. And, I don't trust the Chinese knockoff catch cans on Ebay.

Next draining it once a month, while not incredibly inconvenient, what happens if it's been especially humid/cold or you forget to do it? Have you noticed fill rates varying with climate? Have you experienced any problems after installing it?

What catch can are you running, what installation procedure did you use (two OEM pcvs? pcv + check valve from Matt, etc.), what area of the country do you live in, and do you have any freezing issues? Along the lines of how did you install it-- how have you set it up to drain the can?

I'm just trying to address some of the concerns that come up when you install an OCC.

I sent Crawford an email asking if they had any solutions/products for our cars:

I wasn't asking for a custom solution for myself in particular, and I responded as such, but this could show some promise for other options for our cars.

Long story short, the added maintenance of the OCC really turns me off, and I like the idea of a closed loop system with respect to ease of use, retaining oil, etc. For the people that argue "I wouldn't want that recirculating through my system." I'm fairly certain that the amount of fuel blowby that you catch in the OCC is only going to be a small portion of the fuel still diluted in your oil. Moisture content is always going to be there, etc. If you're changing your oil regularly. Say, every 3000 miles and just using the car as a DD, I suspect the AOS is superior.

However, if you're running a heavily modified car, racing, and so on-- the OCC might be the way to go.

I drilled the bottom of my OCC and tapped it for 3/8" NPT, then put a small nipple on it and a ball valve. I drilled a hole in my undertray so that the nipple and valve stick through so I can just open the valve without removeing the undertray or even jacking up the car.

I usually just open it up and dump it in a store parking lot somewhere about once a week.

I'm running two PCV's, and the can is located under the driver's side headlight, right by the stock horn.

FWIW, the junk that dumps out of my OCC smells strongly of fuel, and seems to have a lot of fuel/water in it. I certainly wouldn't want it going back into my oilpan.

I hope you mean you drain it into a container which you dispose of at a hazardous waste facility. If you mean that you drain it onto the pavement, that is reprehensible behavior.

werd.

and that is a great screen name.

+1 for less maint. i like your way of thinking. make it better and easier instead of just faster. holistic modding has arrived.

Of course that's what I mean.

Well in my case I have an FS Engine in a Protege 5 so it will be set up a bit diferent but the need and reason is very much the same.

In its stock form the Stock PCV is fine, however adding any type of boost to it, seems to make it misbehave. Some people install a Mazda Millenia S PCV (Drop In Part) because it was designed to run in Boost. I did not buy an E-Bay can, It is a simple Aluminum can with Two AN6 Inlets near the top, a drain and a Filter. None of it get pumped into the intake. The intake has been Drilled, Tapped and a threaded set screw is in the hole with White Thread Lock.

Because my car was built to run 400+ Daily HP, I figured that it would be hard to find a reliable check valve that would work. I didn't want the valve closing for long periods of time every time the car went into boost and preventing the air from escaping, just to have some minor scavenging.

The way I saw it, I would rather have the engine able to regulate the pressure all the time, rather than only when off boost. On Boost would mean closing the PCV valve to prevent the boost from inflating the Engine...

While not irrelevant to the discussion entirely, I'm mostly interested in hearing results of these sorts of things on DI engines since ultimately the point is to limit carbon buildup on the intake valves. (And, of course, to reduce blowby and oil buildup in the intake/intercooler/etc.) But running 400 HP to the front wheels is fairly uncommon, so thanks for the details!

In other news. I got another reply from Crawford regarding them looking into an AOS install for the MS3. Not too many details, but there might be more options for our cars in a few months.

You eliminate Carbon buildup by disabling the EGR system, not with a catch can.

My mistake. I'd still like to reduce the rate at which I'm coating my intake in oil. :]

Does anyone vent the crankcase to the atmosphere? It seems like this would solve a lot of peoples concerns. Any negatives to this?

Your car smells like ass, but otherwise no.

i do

yes if you are a hippie

^^ how do you have it vented? And what did u use??

If you do some searching of the forums you will find an answer to all of your questions. This topic has been covered extensively.

i took the hose off and capped off the intake.

your other options are
1)keep the hose and d/c from intake
2)take hose off attach filter (not recommended)
3)run occ