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Old 06-14-2018, 02:51 AM   #1
brandobot
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Default Forged pistons and blow by

I have an IAG stage 1 block and am planning to run an intake, fuel pump, el header, downpipe and catback exhaust with a protune.

How important is it that I run an air oil separator? I donít track the car, and Iím not redlining it every straight away. California smog emission laws are extremely strict here ó having to pay someone to remove and reinstall come time for smog is not feasible for me.
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Old 06-14-2018, 08:03 AM   #2
Scuby04STi
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Quote:
Originally Posted by brandobot View Post
I have an IAG stage 1 block and am planning to run an intake, fuel pump, el header, downpipe and catback exhaust with a protune.

How important is it that I run an air oil separator? I donít track the car, and Iím not redlining it every straight away. California smog emission laws are extremely strict here ó having to pay someone to remove and reinstall come time for smog is not feasible for me.
For what you sound like you plan to do with the car there is zero reason to add and AOS.
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Old 06-14-2018, 01:48 PM   #3
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Default Forged pistons and blow by

i though the street version of IAGís AOS is smog legal? nothing is ever exposed to the air. its a closed system.

i would e-mail IAG and ask.
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Old 06-14-2018, 02:25 PM   #4
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I believe the whole issue with Cali and the AOS is the same as with a non-OEM turbo inlet, etc.

It didn't come with the car, so it's different, so it is banned.
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Old 06-14-2018, 09:34 PM   #5
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Quote:
Originally Posted by Scuby04STi View Post
For what you sound like you plan to do with the car there is zero reason to add and AOS.
???

There are many reasons why an AOS/catch can would be beneficial for what he wants to do with the car.

They arent essential but to say there is zero reason is just wrong.

It depends how much blow-by you are getting. One thing you could do is touch the inside of your intercooler or piping and see if it is oily. If not then dont bother with one, if it is oily it would be a good idea to run one.
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Old 06-14-2018, 10:26 PM   #6
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Quote:
Originally Posted by Harey View Post
???

There are many reasons why an AOS/catch can would be beneficial for what he wants to do with the car.

They arent essential but to say there is zero reason is just wrong.

It depends how much blow-by you are getting. One thing you could do is touch the inside of your intercooler or piping and see if it is oily. If not then dont bother with one, if it is oily it would be a good idea to run one.
There is zero reason to go through the trouble of installing/uninstalling an AOS on a build that should not have a blow-by issue biased on the owners description everytime you need to pass smog.

Do I run one? Yes, it has been very effective and my situation is much different then the OP.
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Old 06-14-2018, 11:09 PM   #7
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It's going to depend on your specific build, I would ask IAG and the tuner, yours isn't going to be exactly the same as every other similar build and you don't want excessive crankcase pressure causing issues with your block and turbo oil seals.
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Old 06-15-2018, 12:51 AM   #8
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Quote:
Originally Posted by 2slofouru View Post
It's going to depend on your specific build, I would ask IAG and the tuner, yours isn't going to be exactly the same as every other similar build and you don't want excessive crankcase pressure causing issues with your block and turbo oil seals.
If he is running oem hoses currently than an aos/catch can wont change the crankcase pressure, it just filters the oil out of the blowby from the pcv. The pcv will be releasing the same amount of crankcase pressure whether you run an aos or not (unless the pcv is not plumbed back to the intake). Oil that gets into the intake air can lower the octane of the fuel in the combustion chamber.

Last edited by Harey; 06-15-2018 at 12:57 AM.
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Old 06-15-2018, 01:12 AM   #9
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He can use larger hose and fittings from the breather vents to allow pressure to get to the inlet tract more easily by enlarging the valve cover vent holes on the cover and adding larger fittings. There is also a company making aftermarket vent fittings that replace the plastic oems. Every bit helps.
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Old 06-15-2018, 01:13 AM   #10
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Quote:
Originally Posted by 2slofouru View Post
He can use larger hose and fittings from the breather vents to allow pressure to get to the inlet tract more easily by enlarging the valve cover vent holes on the cover and adding larger fittings. There is also a company making aftermarket vent fittings that replace the plastic oems. Every bit helps.
I realize the primary purpose of an aos is to remove some oil vapor.
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Old 06-15-2018, 01:15 AM   #11
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Was attempting to add another reply, because my phone won't let me edit. Oops
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Old 06-15-2018, 12:34 PM   #12
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i though the street version of IAG’s AOS is smog legal? nothing is ever exposed to the air. its a closed system.

i would e-mail IAG and ask.
Not carb legal. Technically it doesn't have an impact on emissions since it's not venting to atmosphere, but because it tampers with the stock pcv system, it is considered illegal.

I took off my intercooler and did notice a thin film of oil on the intercooler/throttle body coupler. I also tried leaving my intercooler sideways for 2 nights and only noticed a small trail of oil. (I'm currently at stage 1+ with cobb's intake and catback)

Just heard back from my tuner and he recommended an AOS due to the increased boost at stage 2 (at an install cost of $360.. not including the actual AOS which is $400)

Are there any more easily reversible and affordable catch can/aos type system solutions out there?
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Old 06-15-2018, 12:57 PM   #13
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Well, you could simply buy the AOS and install it yourself
$360 saved.

Come Inspection time, remove AOS and go back to stock, then reverse the process after you pass emissions
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Old 06-15-2018, 07:47 PM   #14
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Quote:
Originally Posted by brandobot View Post
I have an IAG stage 1 block and am planning to run an intake, fuel pump, el header, downpipe and catback exhaust with a protune.

How important is it that I run an air oil separator? I donít track the car, and Iím not redlining it every straight away. California smog emission laws are extremely strict here ó having to pay someone to remove and reinstall come time for smog is not feasible for me.
an AOS is legal to have in California BTW.
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Old 06-16-2018, 10:22 AM   #15
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All new porsches have a built in AOS, just saying.
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Old 06-16-2018, 10:23 AM   #16
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Originally Posted by ProjectXT View Post
All new porsches have a built in AOS, just saying.
Now that's some forward thinking right there.
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Old 06-16-2018, 10:49 AM   #17
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alot VWís have them too.
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Old 06-16-2018, 11:17 AM   #18
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Originally Posted by subaru_gc8 View Post
an AOS is legal to have in California BTW.
I went to my smog local smog guy and they told me any modification of the pcv system will make it fail smog.

Where did you find an aos is carb legal?
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Old 06-16-2018, 11:51 AM   #19
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You'll benefit even more from AOS with the forged pistons since they naturally will have more blowby especially as the car warms up

The 991.2 turbo motors are all closed deck too
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Old 06-16-2018, 04:53 PM   #20
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Quote:
Originally Posted by brandobot View Post
I went to my smog local smog guy and they told me any modification of the pcv system will make it fail smog.

Where did you find an aos is carb legal?
its doesnt need a carb eo number. Your smog guy doesnt know what hes talking about. Ill get the document for you

Here it is
https://www.bar.ca.gov/pdf/APPENDIX%...%2012-2009.pdf

got to page 2

Last edited by subaru_gc8; 06-16-2018 at 05:04 PM.
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Old 06-16-2018, 06:54 PM   #21
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Quote:
Originally Posted by user1029 View Post
You'll benefit even more from AOS with the forged pistons since they naturally will have more blowby especially as the car warms up

The 991.2 turbo motors are all closed deck too
Don't those things basically have aluminum cylinders with steel, of some type, sprayed on in some crazy thin layer?

(No thanks-I'll take my 1/8" iron cylinders
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Old 06-17-2018, 02:04 PM   #22
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You just invested a pretty penny in getting the built motor, do yourself the favor and protect your investment by getting the AOS
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Old 06-17-2018, 03:54 PM   #23
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Quote:
Originally Posted by ProjectXT View Post
All new porsches have a built in AOS, just saying.
Several german vehicles have been using them oem for many years, not new technology.

The issue isn't running an aos, it's running an aftermarket aos that wasn't designed into the oem system when it's emissions levels were factored into its original design.
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Old 06-18-2018, 10:21 AM   #24
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technically with IAGís system, you are ďaddingĒ to the oem pcv system and not modifying it. the original pcv system is still in place and 100% functional.

while radium and killer B both eliminate the pcv valve so theirs would be modifying it.
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Old 06-28-2018, 03:17 AM   #25
kobi sti
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What about the crawford aos?
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