How does an AOS work?

WE'RE BACK! Ever wonder why you need an AOS and how it works? That's exactly what we're talking about in this week's Two Minute Tuesday!
WRX
IAG Performance V3 Comp Series AOS: www.subispeed....
IAG Performance V3 Street Series AOS: www.subispeed....
Cobb Tuning AOS: www.subispeed....
Killer B AOS: www.subispeed....
STI
IAG Performance V3 Comp Series AOS: www.subispeed....
IAG Performance V3 Street Series AOS: www.subispeed....
Perrin AOS: www.subispeed....
Grimmspeed AOS: www.subispeed....

[@mysteriousguy019]

About time someone mentions the difference from both. Knowing AOS you don't have to clean out (to often maybe!?) Seems I'll be going that route now, Thanks Kevin for the info!

[@charliemagnegutierrez9979]

This very helpful and lot of things learned on this video just got an aos today

[@andyzimmy1110]

Could we get a video of like a check list of things you should do when you buy a sti

[@mothervader1559]

and a wrx please

[@nikesbeast]

Really depends on how much you’re willing to spend.. this is an extremely addictive and expensive hobby

[@ran97396]

To reduce cylinder temps or lower the chance of engine knock, this is what I understand you’ll need based on what I’ve found on NASOIC, Reddit, and all the WRX/STI KZbinrs: - AOS: prevents oil vapor from mixing with gasoline vapor and lowering octane that would produce knock - Equal Length Headers: reduces chance of cylinder 4 overheating due to longer length piping on driver side from unequal length headers (no more subi rumble though) - E85/Flex Fuel: lower combustion temps from methanol

[@j.s.3414]

Only question you need to.know is "has it been previously owned". If "yes", don't buy it.

[@mothervader1559]

@@j.s.3414 mine is pre owned lol. why not?

[@geza96]

That’s learned knowledge. Well done. Thanks. Got to watch a few times to fully understand

[@rawrss]

How big of an issue is this for a stock WRX 2015+? Should a WRX being driven as a daily driver (no tracking) be as worried? Thanks SubiSpeed!

[@nikesbeast]

You’re fine without it but once you start modifying and driving spiritedly then yes you should definitely invest in the longevity of your engine

[@Ejpastor32]

Maybe a checklist for top 5 to buy for any turbo cars especially for wrx or sti

[@woodyscrappyopenings5707]

Is there a way that you can show how the compressive tuning air blades work, cuz I prefer those over the perrin and grimmspeed

[@SubiSpeed]

None of them work well unless you have aftermarket fenders with vents or you cut vents into your OEM fender. Mostly aesthetics otherwise.

[@michaelhernandez8418]

The air blades are nice but stupid expensive and yeah cut out your fake fender vents on newer STIs

[@thadragon31]

I have the Perrin front strut tower. So this IAG AOS will not fit with the Perrin?

[@FarDrizzz]

Nice

[@dominikcochrane5580]

What strut tower braces work with the AOS? I bought a Perrin one off your website a few months ago and it won’t clear the AOS. Just wanna find out that will and is of quality.

[@SubiSpeed]

We run the Cusco strut tower brace which clears.

[@716Flat4]

So wait, if the catch cans get both oil and coolant mixed making that frothy death...how does an aos prevent that mix? you cant be dumping that back into the engine!?

[@ashed4456]

Would this help a problem with oil consumption on a 2017 wrx?

[@SubiSpeed]

Yes!

[@bolarobric]

Just bought a used 2017 STI with 79K on it. I know I really need this so I am trying to decide which AOS should I purchase for my street STI , would it be the Grimmspeed (affordable) or the IAG.

[@SubiSpeed]

The IAG V3 Street AOS would be a perfect choice for your needs: www.subispeed.com/part/iag-eng-7182-parent-iag-performance-v3-street-series-air-oil-separator-aos#.Y_eCr3bMKiM

[@thedon9670]

your car is well and truly fu4Ked already mate.

[@Grc011]

I was thinking of getting the Cobb one for my 2020 wrx would that one be fine ?

[@curtisdc312]

I heard that the iag and Crawford aos are best on market, haven't tried any out yet but I just bought the iag aos just need to install it

[@4RT0119]

Necessary for an EJ25 Forester XT?

[@ezwa9979]

☝️wats it go with the gas vapors & pressure thats routes back to engine with catch can?

[@j-morecoffeepls]

I have a 2017 WRX with 90k miles. Bone stock. Should I need this?

[@thedon9670]

too late, it's already fuc*ed

[@santoscarrillo2996]

Looking into Perrin or IAG for the AoS anyone thoughts? I have a 2021 wrx base just about 30k miles stock so I figure its time to start more mods first one was the all powerful Cobb Sunshade 😊

[@jonathanmiclat8134]

What do you mean by engine knocking? Fine or Feed back knocking?

[@joen4520]

Feedback knock is noise picked up by the knock microphone, fine knock learn happens when your engine is consistently knocking within a certain rpm range so your engine 'learns' to pull timing at that rpm range

[@ARA1200]

I bought a crawford AOS. Is the IAG one a superior AOS?

[@charliemagnegutierrez9979]

Some said its not some said the radium is superior

[@victortsang1641]

So do I have to replace or clean the AOS? If so how often should I maintain it?

[@Rezluh223]

I have mine, gonna install after walnut blasting. But you install the aos and leave it. No maintenence required.

[@obZidianZ06]

Right.. but which version to go with: street or competition? Car is a streetcar, driven hard, stage 1+ plus for now

[@trigun989]

Competition is only necessary if you have a built engine and will require a custom tune.

[@obZidianZ06]

@@trigun989 ok thanks

[@davconelectric]

😂

[@dandimoski8107]

anyone know if you can run these in zub zero temperatures?

[@Smeedia]

I wouldent, IAG advised that there is a chance the return line will freeze due to moisture build up

[@tprsilvia]

Would that work on a 2017 forester XT?

[@K03sport]

In theory it works on any car that recircs exhaust gases/positive crank pressure into the intake. Just need to know the part of flow from engine to intake...the AOS goes in btwn. Mounting is the next trick.

[@ExTofia]

Second 🥈

[@Menace_sti]

Yooo

[@moisesr7840]

That air rerouted back into the intake track is not clean air. That oil dumped back into the engine is not a good oil, it's deluted, broken down and could well have Carbon build up. You do not wanna dumped none of that back into your engine, that's why oil catch can is better.

[@benmorris7276]

I wish there were more AOS options for the NA Subaru engines like the FB20D in 17+ Impreza. I have a 2019 Impreza and the one reliability mod I want to do is adding an AOS to my car, as where I live is to cold for an oil catch can to work affectively come Winter time

[@jerseyman1O]

Crawford Performance has one.

[@benmorris7276]

@@jerseyman1O thanks I thought they didn't have it in stock but I guess it's a special order or something

[@gabeochoa14]

will and AOS void my warranty though?

[@brandonedwards9812]

A honest dealership should, I say should, extend the warranty after install. But, no bruh, it won't void warranty.

[@aeeseupaii]

Yes

[@channelgreen5949]

Will this void my warranty?

[@skunkiiee7333]

i want your hair

[@_wrx_WHPFaDIT]

Brz or ibr Manifold

[@carlosmore943]

Is a tune required for this ?

[@eddieespino94]

No sir :)

[@misael1396]

Yup

[@elgachoooqueti7204]

Street series-NO Competition series-YES

[@davconelectric]

​@@elgachoooqueti7204why?

[@ezwa9979]

& btw, does this oil which it’s conveniently rerouted back to engine, include all the carbonE gobally guk that’s been rEcNtly premixed with it?🤔😒

[@SubiSpeed]

The IAG swirl pot canister separates oil from the PCV system, before the gasses return to the intake system

[@davconelectric]

​@SubiSpeed that's not what he asked.

[@ezwa9979]

@@davconelectric true, it wasNt quite - the reason I was asking about oil, is because SOME AOS’s claim to return oil to the system(while Ive heard even regular catch cans, which are THEREFORE ALSO AOS’s - do same separation, as you pointed out) - so I guess 1 then has optian(for better or maybe worse), of pouring back into oil fill👋

[@ceanu2983]

no make them every week bro

[@ssamcobalt4956]

Katsuni

[@CarStory]

Subaru dealer told me installing an AOS would void my STI warranty. Should I do it anyway?

[@bmoore8853]

They would have to prove that the AOS is what caused the failure.... if your headunit or combi meter start having issues; if you have a problem with the electronic DCCD, or if your windshield wiper reservoir pump fails (most common things I've been seeing recently with this gen STI that come in for service) then you are fine, if you form a vacuum leak because the AOS lines weren't secured properly then, yeah that would cause them to not honor the warranty because it wasn't their fault the motor failed, it was the vacuum leak that caused you to run excessively lean and then BOOM. My point is if you do things right, you don't have anything to worry about, and if you revert to stock before bringing the vehicle back in after experiencing any issues and stand your ground to the dealership that vehicle is stock and give them no reason to suspect otherwise, SoA will honor the warranty even if dealership gives you a hard time, contact the SoA Customer Hotline and give them the, " I'm a loyal customer and expected reliability and now I'm experiencing a problem and the dealership is treating me like a 16 year old with their first hotrod".... I've seen cars with AccessPorts in the glove box get warrantied for new engines, you just have to be persistent and not a complete tool. Remember the Dealership WANTS to replace your motor under warranty, thats a big job that Subaru of America pays for, and everyone involved gets paid, even Subaru of America in the end.

[@Bert-zi3ew]

Subaru warranty is a hassle, even when staying stock. I've had my 17 STI Short block replaced under warranty at 18k from a random incident of poor quality fuel that compromised the life of my EJ a year later. My STI only had a axle-back and that alone made them investigate if my motor was tuned or modded. Wait till your warranty's over or near, that's just my advice/opinion.

[@bmoore8853]

@@Bert-zi3ew .......Wow, This is exactly my point: You got very lucky. They replaced your engine for free because you purchased crap gas, that's absolutely not covered by warranty. My Dealership wouldn't have done that, and we bend over backwards and take it with a smile on the regular.

[@nixwrx]

basically buy a AOS= less chance of boom boom?

[@xil3ntkha0s]

It basically is a preventative measure.

[@davconelectric]

No

[@K03sport]

Voodoo? Or is it sorcery?

[@jason2strife]

install vid?

[@SubiSpeed]

kzbin.info/www/bejne/a5LGgqWiZ62Unrc

[@jason2strife]

@@SubiSpeed nice

[@zakuraayame5091]

From what I understand, if you 'need' an AOS, then there is something wrong with the factory system's built in AOS systems ... If you treat a symptom and not the cause, you are taking advil for a broken bone. You can relieve the pain for extended periods of time, but it won't fix it.

[@ran97396]

EJ’s and FA’s don’t have an AOS in the factory PCV system. In fact, it’s a design flaw for all modern direct injection engines, since the ringland gaps for each cylinder will always allow oil vapor into the combustion chamber albeit only in small amounts, but it will build up more carbon and lower octane rating in the cylinder over time since its mixing with gasoline vapor. Lower octane = knock.

[@zakuraayame5091]

@@ran97396 over time? would it not be instantly dealt with? or on that trip? Minus people who consistently drive 5 minute trips? My vehicles run for a minimum of 20 minutes to get to anywhere and back; actually to get to most places. Blow by oil dilution and other issues just aren't a problem in our neighborhood. The combustion chamber is being flushed with a solvent, called gasoline. You shouldn't be seeing carbon buildup in the rifling of your cylinder walls from a bit of blow by which happens in all engines including rotaries. Usually the issue with direct injection that doesn't also include port injection is the PCV systems built in control is broken allowing over many thousands of miles a build up prior to the combustion chamber. If your intake needs to be walnut blasted as an example. It is fun, when I have time, I'll have to dive in to it more. I don't care if people have them; and an added layer of protection is a great idea considering enthusiast tend to be enthusiastic about their power goals. Prevention of catastrophe from extra layers like an AOS or just great maintenance routines and care. But does Carol Channing who picked up a stock STi and Dwayne Johnson in a CVT WRX Series.White need to rush out and buy an AOS because their engine will last half as long if they don't? Getting groceries and running chores needs an AOS? If not, then at what point is it redundant for most consumers and at what point is it a really smart idea? That is what I'm getting at. This video will get the person who likes cars and bought a WRX to think this is a must have. Their spirited driving is your grandma driving. They will never stress the engine or keep it in high revs ... hell I've seen people think 3k is high revs before. So I imagine this person owning an WRX and added an AOS; and their car will never go above 4k rpm. You think that was money well spent? How about a similar person with a BRZ? It has port injection, so no worries with intake blasting! Family member has one outside with nearly 70k on a 2018. It is happy as a lark and no AOS in sight. Plugs showed no abnormal wear or carbon build up. all looked good at its tune up. Again, if you are tracking your car, keeping it above 4k for minutes/hours at a time ... you need an AOS among many other more important things. If your rush is getting up to 70+ on an onramp to set cruise control for a 30+ minute ride to work ... an AOS is probably not in your 'NEEDS' list at all.

[@aspenwagon04]

@@zakuraayame5091 This is a short sighted take. When your car starts to age you will benefit from this. A brand new car maybe not as much.

[@benmorris7276]

No an AOS is always a good idea for reliability when it comes to GDI engines as it will prevent the possibility of oil get in your intake manifold creating carbon build up. From what I understand most cars don't come with an AOS from Factory and only have a PCV valve