FA20 Closed-Deck Short Block 86.1mm Bore

The IAG Performance 800 Series FA20 is a closed-deck short block engineered for modified FA20 Subaru BRZs, FRS, and GT86 models, particularly those utilizing larger aftermarket turbochargers and requiring a stronger foundation to withstand increased cylinder pressures. This short block strengthens the OEM FA20 cylinder walls through its proprietary closed-deck cylinder support system and IAG Spec H-Beam forged connecting rods. Construction involves new OEM Subaru FA20 case halves, machined for enhanced oil flow and to accept IAG Closed Deck Inserts, which bolster the block while preserving coolant flow. To ensure reliability under high-pressure conditions, the design incorporates O-ring receiver grooves and tapped holes for 1/2" head studs, reducing the likelihood of head gasket failure. The block is precision-bored and honed to 86.1mm, accommodating IAG-Spec 86.1mm JE FSR forged pistons crafted from 2618 T6 Alloy. These pistons feature asymmetrical skirts for reduced friction and weight, along with smooth dome and dish radii for efficient flame travel, and are secured by .905 x 2.250" x .210" carbon steel wrist pins. Assembly includes a new Subaru FA20 crankshaft (2020+ model year), ACL or King main bearings, IAG Spec H-Beam rods with ARP2000 rod bolts, and King or ACL rod bearings. OEM bolts, sealant, and standard Subaru case bolts are used, with an OEM oil plug preinstalled at the oil pan location. The compression ratio is set at 10.5:1 with a standard gasket thickness. This short block is ideal for fully built, bolt-on, and upgraded turbo BRZ applications, addressing stock FA20 case weaknesses in lubrication under increased loads. Note: Head studs are sold separately. This product fits the 2013-2021 Subaru BRZ, 2013-2016 Subaru FRS, and 2013-2021 Subaru GT86.