FA20 DIT Closed Deck Short Block

The IAG 800 FA20 DIT Short Block is designed for modified 2015–2021 Subaru WRX vehicles that require a stronger bottom end to support increased cylinder pressures from higher boost and larger turbochargers. It incorporates a proprietary closed-deck cylinder support system, which significantly strengthens the OEM FA20 cylinder walls, creating a robust foundation for high-power engine builds. This short block is constructed using 100% new components. It begins with brand new Subaru FA20 engine case halves that are precision machined for improved oiling. IAG’s closed deck inserts are installed using Haas CNC equipment, creating a solid deck while maintaining essential coolant flow. The block is further CNC machined with O-ring receiver grooves and drilled and tapped to accept ½″ head studs, which greatly reduces the likelihood of head gasket failures under high cylinder pressure conditions. After deck plate boring and honing to 86.25 mm, the short block is assembled with a new Subaru FA20 DIT WRX crankshaft paired with high-performance ACL or King bearings. The build is completed with IAG-Spec H-Beam rods featuring ARP2000 rod bolts and IAG-Spec 86.25 mm forged pistons. The internal oil passages of each new OEM case are carefully inspected and modified by IAG to ensure adequate oil flow for optimal performance and durability. The IAG-Spec JE FSR 86.25 mm forged pistons are crafted from 2618 T6 alloy and feature an asymmetrical skirt design. This design reduces weight and improves combustion efficiency while being capable of supporting higher cylinder pressures. Included components consist of brand new OEM Subaru FA20 case halves (bored and honed to 86.25 mm), modified case halves for improved oiling and O-ring deck surface, and provisioning for ½″ head studs (studs sold separately). It also includes IAG-Spec JE 86.25 mm forged pistons with ring set, IAG-Spec H-Beam connecting rods with ARP2000 rod bolts, ACL or King race bearings, a new Subaru FA20 DIT WRX crankshaft, standard Subaru case/main bolts, and an OEM oil plug preinstalled at the oil pan location. The compression ratio is 10.5:1 with a standard gasket thickness, and the power rating is up to 800 BHP.