IAG 950 EJ25 Subaru Closed Deck Short Block – Subaru

$8,161.23

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Documents

Installation Instructions & Videos

IAG 950 EJ25 2.5L SUBARU SHORT BLOCK

Stage 2 Short Block H-Beam Connecting Rods

RACE ON SUNDAY, WORK ON MONDAY

The IAG 950 Short Block is the ultimate “weekend racer” block. Built to withstand up to 950 BHP, this is our strongest “Street” short block offering. The IAG 950 short block features +2mm IAG Spec H-Beam forged connecting rods, IAG-Spec JE Pistons with electroless nickel plated coating with H13 tool steel wrist pins, and our venerable “Fire-Lock™” head gasket system for 14mm head studs. Each IAG 950 short block is hand-assembled using ACL or King rod and main bearings. This combination of parts makes the IAG 950 the perfect block for drag or road racing.

BUILT WITH 100% NEW COMPONENTS

The IAG 950 Short Block starts with brand new Subaru 2.5L engine case halves. Our machinists’ machine the assembled case halves in our Haas VF-4SS CNC mill to accept the IAG Closed Deck inserts, transforming the block into a solid deck. Next, a deck pair of deck plates are attached and the short block is bored and honed to 99.75mm in our in-house Sunnen SV-30 computer-controlled cylinder hone. IAG’s in-house honing process allows us to set custom piston-to-wall clearances to ensure quiet operation and reduced oil consumption. The Haas mill also cuts a groove at the top of each cylinder to accept the Fire-Lock™ head gasket rings and drills each head bolt hole for 14mm head studs. The modified case halves are then assembled using a new 2017+ Subaru 2.5L nitride-treated STI crankshaft and IAG-Spec Tuff H-Beam connecting rods with ARP rod bolts. IAG Short blocks feature ACL or King Race rod and main bearings and are all balanced and blueprinted. Finally, the case halves are sealed with new OEM main/case bolts and sealant.

EJ25 STI Crankshaft
IAG Fire-Lock Head Gasket System

NEVER WORRY ABOUT HEAD GASKET FAILURES

The IAG 950 EJ25 Closed Deck Short Block features our proprietary “Fire-Lock™” Head gasket system. This system has been proven in our record-setting race cars to be the strongest Subaru head gasket system ever produced. To achieve these results our engineers separated the combustion chamber sealing from the fluid sealing aspects of the head gaskets. Our machinists carefully machine a lip at the top of each cylinder to accept the “Fire-Lock™” ring. With the ring locked in place, it stands proud above the deck, providing a superior seal. The separate gasket bodies take care of sealing oil and coolant passages and keeping them out of the combustion chamber. 14mm Head studs (Not Included) hold the assembly together.

CLOSED DECK FOR EXTRA STRENGTH

Our unique closed deck system significantly increases the strength of the OEM case halves. This process supports the cylinder walls at the top of the case in order to prevent flexing and possible cracking where the case bolt reliefs are cut into the back of the cylinder wall.
During the installation process, we machine the assembled case halves in our Haas VF-4SS CNC mill to accept the IAG Closed Deck inserts. Once the case has been machined we heat it in an oven while freezing the specially machined inserts with liquid nitrogen. The inserts are then pressed into place and then machined to a mirror finish.
The unique inserts feature small passages that allow needed coolant flow to the deck surface. This means that the closed deck system does not affect the block’s cooling ability and will not cause overheating, even in daily drivers.

IAG 950 Closed Deck Block
IAG 950 IAG-SPec JE Pistons and Rings

PISTONS SPECIALLY DESIGNED WITH POWER IN MIND

The pistons used in the IAG 950 Short Blocks are specifically designed to support the rigors of racing. Designed in partnership with JE, these IAG-Spec pistons feature electroless nickel plating and a 2618 Alloy. Extra thick ring lands resist collapsing under pressure. The upgraded .250″ wall H13 tool steel offset wrist pins are designed to hold up to 950 BHP without bending or breaking. The pistons also feature JE’s Perfect Skirt coating.

IAG 950 Closed Deck EJ25 Short Block 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 for 14mm head studs – *Head studs are 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 Tuff H-Beam +2mm / 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.

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 Rating:

  • The IAG 950 Short Block has a power output rating of 950 BHP

Additional information

Weight60.00 kg
Dimensions50.00 × 50.00 × 45.00 cm

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Applications

Models suitable for this product

MakeModelYearSubmodel
MakeModelYearSubmodel
SubaruBaja2004 - 2006XT - 2.5L Turbo AWD
SubaruForester2004 - 20132.5XT
SubaruImpreza2004 - 2014WRX STi
SubaruImpreza2006 - 2014WRX
SubaruLegacy2005 - 20122.5GT
SubaruLegacy2006 - 2009Spec B.
SubaruOutback2005 - 20092.5XT
SubaruWRX2006 - 2014
SubaruWRX STi2004 - 2021

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