AG Stage 3 Extreme Subaru EJ25 Closed Deck Short Block
The IAG Stage 3 Extreme Short Block starts with brand new Subaru 2.5L engine case halves. 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 larger 1/2" head studs that aids in preventing cylinder heads from lifting in high boost applications. Next, the short block is Deck Plate bored and honed to 99.75mm in our in-house Sunnen SV-30 the most advanced automotive cylinder hone available. IAG‘s in-house honing process is able to set custom piston to wall clearances to best fit your needs. The modified case halves are then assembled using a new 2017+ Subaru 2.5L nitride treated STI crankshaft that is matched to ACL or King race main bearings. Manley Turbo Tuff Tri-Beam connecting rods and ARP rod bolts are utilized along with ACL or King race rod bearings. The case halves are sealed with new OEM main/case bolts and sealant (upgrade to ARP mains and line hone service a la carte). IAG-Spec JE FSR 99.75mm Forged Pistons are chosen to finish the Stage 3 Extreme short block.
Stage 3 Extreme Closed Deck Includes:
Case Halves -Converted to Closed Deck using brand new Subaru OEM case halves, bored and honed to 99.75mm.
O-Ringing -Machine and O-Ringed Deck Surface
Head Studs -Machine case to fit 1/2" head studs - *Head studs sold separately
Pistons -IAG-Spec JE FSR 99.75mm 2618 Forged Pistons, Ring Set, .180" Chromoly wrist pins, Clips, (Perfect Skirt Coating and Offset Wrist Pins)
Connecting Rods -Manley Turbo Tuff Tri-Beam / ARP2000 Rod Bolts.
Rod / Main Bearings -ACL or King Race bearings.
Crankshaft -Standard New Subaru Nitride Treated 2017+ STI Crankshaft.
Case / Main Bolts –Standard FHI Subaru case bolts.
Additional Options Available:
Head Studs -IAG Performance 1/2" head stud set manufactured by ARP - $499.99
Oil Pump -Subaru JDM 12mm High Volume Oil Pump - $219 or 11mm Subaru Oil Pump - $199.95
IAG Oil Pickup -Upgraded oil pickup featuring heavy gauge steel tubing, 2 point bracket & mesh filter - $129.99
Head Gaskets -JE Pro Seal .039" Head Gaskets - (PN# SB1001-039 for D25 & B25 Heads, PN# SB1003-039 for V25, W25 & N25 Heads)
Hardware / Seal Option -$105.99 (Wrist pin plugs, washers, separator cover, bolts, etc. In case you don’t want to transfer from the original engine).
8.5:1 on D Cylinder Heads (EJ255)
8.2:1 on B, V and W EJ257 Heads with standard thickness gasket.
Head Gasket Recommendations:
*IAG Recommends JE Pro Seal .039 inch head gaskets
JE PN# SB1001-039 are for use with S20, B25 & D25 Cylinder Head Castings (2004-06 STI, 06-14 WRX, 04-13 FXT, 05-12 LGT, 02-05 WRX)
JE PN# SB1003-039 are for use with V25, W25 & N25 Cylinder Head Casting (2007-19 STI)
Power: The IAG Stage 3 Extreme Short Block has a power output rating of 800BHP.