Description:
IAG Stage 3 Extreme FA20 DIT Closed Deck Short Block
The IAG Stage 3 Extreme short block starts with new Subaru FA 2.0L engine case halves that are machined for improved oiling. Then IAG machines the case halves assembled together in our Haas VF-4SS CNC mill to accept the IAG CLOSED Deck Inserts that transform the block into a solid deck. The unique inserts feature small passages that allow needed coolant flow to the deck surface. The case halves are then CNC machined with O-ring receiver grooves around the bore surface as well as drilled and tapped to accept 1/2″ head studs that greatly reduce head gasket failure during high cylinder pressure scenarios. Next, the short block is Deck Plate bored and honed that to 86.25mm on our in-house Sunnen SV-30 the most advanced automotive cylinder hone available. IAG’s in-house honing process is able to set piston to wall clearances tighter for a quieter running engine. The short block is measured and assembled using a new 2015-20 Subaru 2.0L WRX crankshaft that is matched to King main bearings. IAG-Spec I-Beam rods with ARP2000 rod bolts are utilized along with King or ACL rod bearings. The case halves are sealed with new OEM case bolts and sealant. Finally, IAG-Spec 86.25mm forged pistons are spec’d and installed along with an OEM oil plug finishing off the short block.
Stage 3 Extreme FA20 Includes:
Case Halves -Converted to Closed Deck using brand new Subaru OEM case halvesCase Machining – Modified for improved oilingCase Machining – Bored and honed to 86.25mmO-Ringing – Machine and O-Ring Deck SurfaceHead Studs – Machine Case to 1/2″ head studs – * Head studs are sold separatelyPistons -IAG-Spec 86.25mm Forged Pistons, Ring Set, and .150″ x 2.250″ Chromoly Wrist Pins.Connecting Rods -IAG-Spec I-Beam / ARP2000 Rod BoltsRod -ACL or King XPGMain Bearings -King XPGCrankshaft -New Subaru FA20 DIT WRX crankshaftCase / Main Bolts -Standard Subaru case boltsHardware – OEM Oil Plug – comes preinstalled at the oil pan location
Additional Options Available:
Oil Plugs & Rear Main Seal – (x1) 11021AA190 Plug, (x2) 11024AA141 Plugs , (x1) 806792010 Rear Main SealHead Studs – IAG Performance 1/2″ head stud set manufactured by ARP
Compression Ratio:
10.6:1 (stock compression) on standard gasket thickness.
Power: The IAG Stage 3 Extreme Short Block has a power output rating of 800BHP
*All IAG Short Blocks are balanced and blueprinted.
Vehicles:
- 2014 – 2018SubaruForester
- 2015 – 2021SubaruWRX








