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-   -   Air Oil Separators? (http://legacygt.com/forums/showthread.php?t=196236)

dahoseman 11-12-2012 09:35 AM

Air Oil Separators?
 
I've got a pile of parts collected for a build and waiting for a few to show up. One thing I was considering was an air oil separator.

1. Does anyone have any advice on these?
2. I know that they are theoretically beneficial for emissions/octane degradation, but I'm an evidence guy. Would I ever notice the difference between having one and not having one? What benefit would be noticeable to an owner?
3. I was considering the Grimmspeed AOS, which is "set it and forget it" style. I saw this thread recommending against that design
http://legacygt.com/forums/showthrea...+oil+separator

Can anyone explain the recommendation against it and what they would recommend?

Max Capacity 11-12-2012 10:02 AM

I have one that sits on the oil fill tube on my wagon. In the cold weather the moisture forms on the inside of it.

That's way Crawfords can has a coolant hose going to it to keep it warm.

I won't do this again.

CapnJack 11-12-2012 05:16 PM

The Crawford V2 is the one of the best ones out there. The biggest thing to ask is "What are you going to do with your car?" If you plan to track your car (making high G corners), it has been discussed at length that the Crawford unit works best. If you just plan on normal DD activities, the GS unit is very nice and will work well for less money. If you do decide on a Crawford unit, I purchased mine from Circuit Motorsports. They were the cheapest place on the web that I found.
Disclaimer - I have NO affiliation with Circuit, just trying to pass along the savings I found after an exhaustive search.

dahoseman 11-14-2012 01:22 PM

Thanks for the info. I'm going to do a little research on these babies and perhaps install one.
I'm curious about the results of having one. Is there any tangible benefit that an owner would notice? Is it one of those things where an engine will run for maybe 250,000 miles instead of 200,000 miles with an air/oil separator installed?

Max Capacity 11-14-2012 01:23 PM

No,

No noticeable difference.

Put your money somewhere else.

CapnJack 11-14-2012 06:10 PM

Quote:

Originally Posted by Max Capacity (Post 4158890)
No,

No noticeable difference.

Put your money somewhere else.

This man is correct.

ibr_adam09 11-14-2012 06:22 PM

I got one only because it was for $60. the gs unit.

Aracheon 11-14-2012 06:45 PM

I'm running the dual Moroso setup... one can for the heads, one can for the crankcase.

The head can hasn't caught more than a drop, but I haven't taken my car to the track yet, either.

The crankcase can I've had to empty several times in just a few thousand miles.



Worth it? Depends on how you drive, how much oil vapor makes out of the crankcase breather (YMMV), and how much/little you care about your engine ingesting that stuff. The inside of the TMIC on my 09 STi after 60,000mi was nasty as hell... but I also drove the hell out of that car. Commuting, trackdays, hauling motorcycles, ice racing, etc.


There's a 100+ page thread on IWSTI about AOSs/catch cans if you REALLY want to hear the pros and cons... :lol:

Drift Motion 11-14-2012 07:03 PM

I was considering this also, after noticing oil on the turbo to TMIC gasket

EJ25subie05 11-14-2012 08:27 PM

what I'm not understanding is why is it not worth the money? it helps keep the intercooler and all those good ol' parts clean from oil right? or do i have the setup all messed up? enlighten me

kits gt limited 11-14-2012 08:49 PM

I have the Crawford. Recommended by my shop. It can be a slippery slope!!

fahr_side 11-14-2012 09:01 PM

Quote:

Originally Posted by EJ25subie05 (Post 4159419)
why is it not worth the money? it helps keep the intercooler and all those good ol' parts clean from oil right?

At 60,000km I have barely a noticeable film of oil in my intake. I won't be fitting an AOS until that changes.

EJ25subie05 11-14-2012 09:16 PM

i have 35k and i notice it, maybe because i run my car hard?

Aracheon 11-14-2012 09:58 PM

Quote:

Originally Posted by EJ25subie05 (Post 4159419)
what I'm not understanding is why is it not worth the money? it helps keep the intercooler and all those good ol' parts clean from oil right? or do i have the setup all messed up? enlighten me

It's one of those things where the products don't always have a quantifiable improvement. It's not like flashing your AP to Cobb Stage 2 from stock and noticing an immediate difference.

The products and solutions offered are rather expensive, and not all LGTs have issues with massive amounts of PCV oil consumption. Subaru engineered a catch-all solution in their PCV system that DOES work, but it does have side-effects.

Personally, I don't like having oil in the intake tract, so I opted to put Moroso AOSes on my car.



Quote:

Originally Posted by fahr_side (Post 4159461)
At 60,000km I have barely a noticeable film of oil in my intake. I won't be fitting an AOS until that changes.

A good reason NOT to bother with an AOS... "if it ain't broke, don't fix it." If I hadn't seen a lot of oil inside my TMIC on both my STi and my LGT, I wouldn't have bothered with an AOS either.

BAC5.2 11-14-2012 10:29 PM

Is it a street car? You don't need an AOS.

If you think you need an AOS, ask yourself why.

If it's because you think you have excessive oil in the intake? An AOS isn't going to fix any issue you have. It's putting a bandaid on a bullet wound if your PCV system is pumping that much oil into the intake.

If you want the intake to be squeaky clean and oil free, ask yourself why you want that. I'm willing to bet you can't come up with a sufficiently good reason.

At the end of the day, it's your money. You'll spend it how you want, and you'll convince yourself enough to have made that decision.

If it were MY money, I'd spend it elsewhere without any hesitation.

The ONLY valid reason for an AOS, is on a car that is tracked and is equipped to actually be capable of having PCV problems in high-G, high duration turns. I'd put money that less than 1% of our member base fits that description.


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