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IAG Stage 4 TUFF EJ25 Subaru Closed Deck Short Block For WRX | STI | Legacy GT | Forester XT


IAG Stage 4 TUFF EJ25 Subaru Closed Deck Short Block For WRX | STI | Legacy GT | Forester XT

  • Weight: 0 lb
  • Dimensions: N/A
  • Installation Difficulty:
SKU: IAG-ENG-1452 Categories: , ,


IAG Stage 4 Tuff Subaru EJ25 Closed Deck Short Block The IAG Stage 4 Tuff 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 for our new Fire-Lock head gasket solution that is loosely derived from diesel technology where a counterbore step is machined around each cylinder bore allowing specially sized fire rings to drop into the machined area and head gasket bores. The Stage 4 Tuff case is then drilled and tapped to accept 14mm head studs that combined with the IAG Fire-Lock head gasket set greatly reduces head gasket failure during high cylinder pressure scenarios. 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. Custom IAG TRI-BEAM 2mm connecting rods by Manley and ARP 625 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 (upgrading to ARP mains requires line honing). Finally IAG-Spec 99.75mm JE FSR 2618 Forged Pistons with electroless nickel plated tops and ring area as well as upgraded .250″ / .906″ H13 wrist pins are added to finish the Stage 4 Plus block. IAG?s custom pistons feature a lightweight design while increasing strength where you need it and are designed to work exclusively with the IAG 2mm Tri-Beam connecting rods. The wrist pin is short and is made from H13 tool steel and the pin piers are profiled to increase pin boss strut. IAG?s pistons feature a 25% larger oil ring for reduced oil consumption and added gas ports that aid ring sealing in high boost conditions. Stage 4 Tuff Closed Deck Includes: Case Halves – Converted to Closed Deck using brand new Subaru OEM case halves bored and honed to 99.75mm. Fire-Lock – IAG Fire-Lock receiver groove machining latest solution to prevent head gasket failure on high horsepower and high boost Subaru’s – *IAG Fire-Lock head gaskets required Head Studs – Machine case to fit 14mm head studs – *Head studs sold separately Pistons – IAG-Spec JE FSR 99.75mm 2618 Forged Pistons Electroless Nickel Plated Tops & Ring area Ring Set .250″ / .906″ H13 Wrist Pins Clips (Perfect Skirt Coating and Offset Wrist Pins) Connecting Rods – IAG-Spec Tri-Beam 2mm w/ ARP 625 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: Oil Pump – Subaru JDM High Volume Oil Pump or Subaru 11mm Oil Pump Head Gaskets – IAG Fire-Lock .051″ Head Gaskets with IAG-Spec Alloy Ring Set* Required for use with this short block Head Studs – IAG / ARP Spec 14mm head studs nuts and washers Hardware / Seal Option – (PN# IAG-ENG-1720) Wrist pin plugs washers separator cover bolts etc. In case you don?t want to transfer from the original engine. Compression Ratio: 8.5:1 on D Cylinder Heads (EJ255) 8.2:1 on B V and W EJ257 Heads with standard thickness gasket. Head Gasket Required: *IAG Fire-Lock .051″ Head Gaskets with IAG-Spec Alloy Ring Set* PN# IAG-ENG-1740 Power: The IAG Stage 4 Tuff Short Block has a power output rating of 1000BHP. *All IAG short blocks are balanced and blueprinted.

Make Model Submodel Year
Subaru Forester XT 2004 - 2013
Subaru Impreza WRX 2002 - 2014
Subaru Impreza WRX STI 2004 - 2014
Subaru Legacy GT 2005 - 2009
Subaru WRX STI 2015 - 2018
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