IAG Stage 2.5 International Hybrid EJ25 Subaru Closed Deck Short Block (For Use w/ EJ20 Heads)
IAG Stage 2.5 International Hybrid Subaru EJ25 Closed Deck Short Block
The Hybrid EJ25 Short Block is designed for enthusiasts that want to increase the displacement and low end torque of their vehicle that originally was equipped with the EJ20 2.0L engine. The Hybrid 2.5L features pistons that are designed to lower compression and match the EJ20 cylinder heads without the need for cylinder head chamber modification.
Each IAG Stage 2.5L Hybrid 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. 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. IAG-Spec Tuff H-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 (upgrading to ARP mains requires line honing). Finally, IAG-Spec 99.75mm JE FSR 2618 Forged Pistons with .210" Steel Wrist Pins are added to finish the Stage 2.5 short block.
Stage 2.5 Closed Deck Includes:
- Case Halves -Converted to Closed Deck using brand new Subaru OEM case halves, bored and honed to 99.75mm.
- Pistons - IAG-Spec JE FSR 99.75mm 2618 Forged Pistons, Ring Set, .210" Steel Wrist Pins, Clips, (Perfect Skirt Coating and Offset Wrist Pins)
- Connecting Rods -IAG-Spec Tuff H-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:
- Oil Pump - IAG Stage 2 CNC Ported EJ 11mm Oil Pump or Subaru JDM 12mm High Volume Oil Pump
- IAG Oil Pan Packages - Upgraded 2.5L Oil Pan, oil pickup, baffle and windage tray *Requires use of 2.5L dipstick sold separately.
- Hardware / Seal Option - (Wrist pin plugs, washers, separator cover, bolts, etc. In case you don't want to transfer from the original engine).
Power: The IAG Stage 2.5 Short Block has a power output rating of 700BHP.
*All IAG short blocks are balanced and blueprinted.
Compression Ratio: 8.5:1 on S20 Cylinder Heads
Oil Pickup & Pan Packages:
IAG offers a number of oil pickup, pan, baffle and windage tray options to help you complete your engine build. When completing a Hybrid build it is important to note that switching to our oil pickup requires the use of a EJ25 oil pan and dipstick.
About the V2 Oil Pickup:
It's well-known that the OEM oil pickups often crack and fail which in most cases destroys your engine from lack of oil pressure. To avoid the cracking failures seen in the OEM oil pickup tubes, IAG’s oil pickup is manufactured from heavy-gauge steel tubing that is 2x thicker than OEM. It features a machined 3/8" stainless steel flange, which mates to the block with a Viton O-ring. The integrated heavy-duty stainless steel mounting bracket uses two mounting points rather than the OEM single mounting point. Furthermore, the oil pickup features a formed bottom with an OEM style mesh screen for proper filtration. The TIG-welded oil pickup increased material thickness matched with the two-point heavy-duty mounting bracket helps ensure it does not fatigue and fail over time like an OEM unit.
The IAG V2 Oil Pickup is available separately or in one of two types of packages. The first package bundles the pickup with our windage tray and oil control baffle, enabling you to utilize a EJ25 pan of your liking. The second package includes our V2 Oil Pickup along with a Street or Competition Series Baffle and Windage Tray combined with our new Oil Pan.
About The Pans:
IAG's cast aluminum and CNC machined oil pans suit a wide range of street and track applications with fitment for a larger variety of popular headers in mind, while still increasing oil capacity up to 30% over OEM.
The pans incorporate cooling fins to dissipate heat from the oil as air passes over them. The included oil drain plug is integrated into the lower cooling fins at the absolute bottom of the pan to ensure all the waste oil is removed during maintenance changes. The pan is also threaded with 1/8th inch NPT port to accept many popular oil temperature sensors. 1/8th inch NPT plug is also included in the event that the sensor port is not used.
The upper flange mounting surface is CNC machined for better hardware fitment and features a sealing O-ring for easier installation and removal. Furthermore, the pan is designed to use the included OEM style Viton dipstick o-rings with a unique chamfer to aid in the installation of the dipstick.
About Street Series Oil Baffle
Internally, the pan includes our integrated, stainless steel, Street Series Oil Baffle that is designed to prevent oil inside the pan from sloshing around and creating cavitation, which can lead to oil starvation. The baffle is engineered to be removable for future upgrades and easy cleaning.
About Competition Series Oil Baffle
The IAG Competition Series Oil Baffle is designed to limit potential blow-by and prevent oil starvation in your Subaru's WRX / STI EJ engine during high rpm and high g-force driving. The Competition Series Baffle should be used in vehicles that will see track time, however, it is acceptable to run this baffle on the street as well. The Comp Series baffle is configured with Viton one-way flapper valves which hold oil in the area closest to the pickup. Combining the baffle with the louvers in our windage tray, oil is prevented from reentering the upper crankcase area and is directed down into the oil pan to ensure plentiful supply to the oil pickup.
About The Windage Tray:
The job of the windage tray is to help direct oil from the upper crankcase down into the lower crankcase and oil pan area. Manufactured from stainless steel, precision-formed louvers direct oil downwards and help to prevent oil that is draining from the cylinder heads in the lower crankcase area from sloshing upwards into the path of the crankshaft and connecting rods, thus reducing aeration.
Hardware / Seal Option:
Not planning on reusing your original short block service plugs and covers? IAG offers a simple comprehensive cover and seal kit that includes (1) Rear main seal, (3) OEM wrist pin plugs, (3) OEM wrist pin plug washers, (1) OEM separator cover, (6) OEM separator cover bolts, (1) OEM wrist pin service cover, (1) OEM wrist pin service cover O-ring and (2) OEM wrist pin service cover screws. *If you are reusing your original wrist pin service plugs and covers always replace the (3) OEM wrist pin plug washers and (1) wrist pin service cover O-ring before installing a short block to avoid potential leaks. *Never reuse a rear main seal on a new short block.
Please review the PDF document below regarding installation, break-in procedures and warranty information.