Knowledge Base:  

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AOS - 2015+ Subaru WRX Air Oil Separator - After Install Passenger Window Issue
If you leave the ECU/battery unplugged you may have to reset the switches. If the vehicle's battery is disconnected due to situations such as battery or fuse replacement, the following functions ar
AOS - Does IAG have an Air Oil Separator that fits the 2002-2005 WRX?
Does IAG have an Air Oil Separator that fits the 2002-2005 WRX? Answer: We do not make an AOS specifically for the 2.0L vehicles. You can purchase one for a 2006-07 WRX and relocate your cruise contr
AOS - I have a Street Series AOS & I'd like to make it a Competition Series / I have a Competition Series AOS & I'd like to make it a Street Series
We understand your needs can change and while you purchased a Street Series AOS you may want to convert over to a Competition or vise versa. We have created several kits to make this doable with your
AOS - My AOS appears to be leaking around the top or bottom, but I can't find an actual leak. What's causing this?
Don't be alarmed! We have found is that in some cases the lubrication we use on the o-rings during assembly of the AOS can liquefy under higher engine bay temperatures. The first step to determine the
AOS - Trouble Installing an IAG Air Oil Separator with Aftermarket Turbo Inlet
Having trouble installing an IAG Air Oil Separator with Aftermarket Turbo Inlet? Some aftermarket turbo inlets do not include a port for the blow by sensor and it just leaves the sensor to sit out in
AOS - Which AOS is right for my vehicle?
It is IAG's opinion (which may differ from some builders and tuners) that you should use the following parameters to decide which AOS is correct for your vehicle: Less than 600 WHP on pump gas –
AOS - Why do I have extra parts after completing the AOS install?
The IAG Air Oil Separator kits are packaged in such a way that they fit multiple models and years even though the part number remains the same. Not every model or year uses the same parts that are pac
AOS - Why does my AOS look different than what is advertised on the site?
Our AOS has gone through a series of revisions that often outpaces our instructions or advertising. The biggest change in the last few years was our revised bracket design for the Competition and Stre
Cylinder Heads - How do I know what head castings I have?
Subaru cylinder heads are identified by an alphanumeric code cast into the side of every head. The code features a letter and two numbers. WRX and STI EJ25 cylinder heads have four letter codes (B, V,
Engine - Can I add ARP Case Bolts to an IAG Short Block or Case once it is built or machined?
No! Adding ARP case bolts to an IAG Short Block or IAG Case Half Set after it is machined and built to spec originally with OEM case bolts will cause case distortion and reduce the longevity of the en
Engine - Using IAG EJ25 Short Blocks with 2002-05 Subaru WRX's
The IAG EJ25 short blocks will work with your 2002-2005 Subaru WRX but it will require modifications and tuning. You would need to build what's referred to as a hybrid engine for you to be able to use
Engine - What break-in oil do I use for my new block?
Please read our Short Block and Long Block Install Documentation thoroughly before doing anything with your vehicle and new engine. This link includes the detailed break-in procedure. You can find th
Engine - What head gaskets do you recommend for a Hybrid EJ25 Short Block with 2.0L EJ20 heads?
If you are using our IAG EJ25 Closed Deck short block with 2.0L heads that feature the combustion mod you should use the .039” JE Proseal Gaskets. If you are using a short block with Stock styl
Engine - What type of oil should I run after break-in?
After completing the full break-in procedure: For EJ25 we recommend Motul 5w40 8100 X-cess Synthetic (Pump Gas) and change oil and filter every 2500-3000 miles. If running E85 or Race Gas use Mot
Engine - When using ARP case bolts with an IAG case half set should I follow the ARP torque specs?
No! IAG installs ARP CASE BOLTS with 30W engine oil using OEM SUBARU torque specs and procedures. Other torque specs and lubricants may lead to case distortion damage. If you purchased an IAG case hal
Fueling - I want to buy your side feed to top feed conversion rails, but I don't see any fuel lines for my car. What do I need?
If you choose to use our conversion rails you will be able to run any of the fuel line kits we offer for the 2007-18 STI and 2002-14 WRX. Part Numbers: Side Feed to Top Feed Conversion Rails - IA
Fueling - What do I need to convert from side feed injectors to top feed injectors?
Side feed to top feed conversions can be done two ways: The first way is to run our side feed to top feed injector conversion rails (Part# IAG-AFD-2130). This is the simplest way to do the conv
Fueling - What size fuel injectors do I need?
This is one of the most common questions when starting a build and the great news is there is not any reason to guess as the injector size will be dictated solely by the power you want to make and the
Product Support - Why are my anodized parts (Fuel rails, TGVs, caps, etc) different shades, or look different from the pictures online?
Anodizing is a coating process with many variables which can affect thickness and color. While all care is taken to achieve the best consistency possible, batches of anodized components rarely match e
Product Support - Why does my anodized IAG part have small parts of missing anodizing?
When anodizing an aluminum part, the anodizing coats best on flat surfaces. When dealing with complex shapes, or tight corners, the anodized coating may not adhere properly and a bare spot will be see