Cosworth EJ257 Crate Engine for Sale | Legendary Cosworth Engineering Built
$4,999.00
At a Glance
- Condition: Cosworth-built crate engine, freshly built specification or low-mileage used
- Availability: In stock, Cosworth EJ257 crate engine available subject to availability
- Shipping: Specialty freight handling for crate engine to all 50 states, 7 to 14 business days
- Engine verified as Cosworth-built EJ257 (legendary British motorsport engineering firm Cosworth-engineered Subaru EJ257 crate)
- Cosworth specification documented (Cosworth-developed pistons, rods, crankshaft, head work, oil system, balanced rotating assembly)
- Application confirmed (Subaru WRX STI performance builds, custom Subaru projects, race / track day applications, stage upgrade builds)
- Horsepower potential documented (Cosworth-built EJ257 typically supports 450-700 plus HP capability with proper supporting modifications)
- Internals verified (Cosworth forged pistons, Cosworth-spec H-beam connecting rods, balanced crankshaft, ARP main and head studs)
- Both cylinder heads condition documented (CNC-ported / flowed in Cosworth specification)
- Cosworth oil system verified (high-volume oil pump, baffled oil pan, oil cooler provisions)
- 15 day replacement warranty on internal defects
Description
About the Cosworth EJ257 Crate Engine
Looking for a Cosworth EJ257 crate engine? Part Nests sources OEM-pattern Cosworth-built Subaru EJ257 crate engines for high-performance Subaru WRX STI builds and custom Subaru projects. Cosworth is the legendary British motorsport engineering firm with motorsport heritage spanning Formula 1, IndyCar, World Rally Championship, and decades of engine development for premium performance applications. The Cosworth EJ257 represents Cosworth’s engineering applied to Subaru’s EJ257 2.5L turbo boxer-4 (the STI variant per our listing and the broader EJ25 family), with Cosworth-developed pistons, connecting rods, crankshaft balancing, cylinder head work, oil system, and supporting upgrades. Cosworth EJ257 crate engines typically support 450-700 plus HP capability with proper supporting modifications (turbo, fuel system, ECU, cooling, etc.).
Engine Overview: Cosworth EJ257 Crate Engine Architecture
- Base architecture: Subaru EJ257 2.5L horizontally-opposed boxer-4 turbo (the STI variant /)
- Cosworth specification differences from stock EJ257:
- Forged pistons: Cosworth-developed forged pistons with specific compression ratio, ring pack, and cooling features (stock EJ257 uses cast pistons in some applications)
- H-beam connecting rods: Cosworth-spec forged H-beam connecting rods with higher tensile strength than stock rods
- Balanced rotating assembly: Cosworth-balanced crankshaft, rods, and pistons assembled and balanced to motorsport tolerances
- ARP fasteners: ARP main and head studs (premium aftermarket fastener brand)
- CNC-ported cylinder heads: Cosworth CNC port and flow work on cylinder heads for improved breathing
- Valvetrain upgrades: Cosworth-spec valves, valve springs, and retainers depending on specific build level
- Oil system upgrades: High-volume oil pump, baffled oil pan, oil cooler provisions
- Block preparation: Block honed, decked, and machined to Cosworth tolerances
Cosworth Engineering Heritage Context
Cosworth is one of the most legendary names in motorsport engineering, with heritage that gives the Cosworth EJ257 crate engine its premium positioning:
- Formula 1 heritage: Cosworth’s DFV V8 powered Formula 1 from 1967 through the 1980s, winning more F1 races than any other engine in history
- IndyCar / CART heritage: Cosworth-built engines powered IndyCar / CART racing for decades
- World Rally Championship: Cosworth Engineering was Subaru’s WRC engine partner during Subaru’s most successful rally years (the Subaru / Cosworth WRC partnership produced the engines that defined Subaru rally heritage)
- Aftermarket performance: Cosworth aftermarket performance components are premium-positioned in the Subaru WRX / STI performance community
- British engineering: Cosworth’s UK-based engineering and manufacturing maintains motorsport quality standards
EJ257 vs Cosworth EJ257: What Cosworth Adds
The Cosworth EJ257 (this listing) is a substantially upgraded version of the stock Subaru EJ257 (per our listing and the broader EJ25 family context). Key Cosworth upgrades:
- Horsepower capability: Stock EJ257 typically supports approximately 300-400 HP with proper supporting modifications; Cosworth EJ257 typically supports 450-700 plus HP capability
- Internal strength: Stock EJ257 internals are the limiting factor for big-power builds; Cosworth forged pistons, H-beam rods, ARP fasteners, and balanced rotating assembly substantially extend the safe power capability
- Cylinder head work: Stock EJ257 heads are CNC-machined production castings; Cosworth heads receive CNC port and flow work for improved breathing
- Oil system: Stock oil system is adequate for stock power levels; Cosworth oil system upgrades support sustained high-power operation
- Build quality: Cosworth build process includes more rigorous machining tolerances, balancing precision, and quality control than mass-production engines
- Cost: Cosworth EJ257 represents a substantial cost premium over stock EJ257 (approximately 2-5x cost) reflecting the engineering content
Cosworth EJ257 Application Context
- Performance Subaru STI builds: Owners building 450-700 plus HP STI applications use Cosworth EJ257 as the foundation engine
- Track day / time attack applications: Cosworth engines withstand sustained high-RPM operation common in track use
- Rally / rallycross applications: The Cosworth EJ257 heritage from Subaru WRC partnership makes it a natural choice for rally builds
- Custom Subaru projects: Engine swap projects, restomod builds, and other custom Subaru applications
- Stage upgrade builds: Owners upgrading from stock EJ257 to support higher power often choose Cosworth as the upgrade engine
Subaru Boxer Engine Family Context
The Cosworth EJ257 crate engine (this listing) is the premium Cosworth-built Subaru EJ257 crate engine for performance applications. For broader Subaru EJ family context across our catalog and prior batches, the Subaru EJ257 engine (our listing) covers the stock OEM EJ257 STI engine; the Cosworth EJ257 is the upgraded performance variant of that base engine. The Subaru EJ255 engine (our listing) is the related lower-output WRX turbo variant. The Subaru EJ25 Turbo engine (our listing) covers the broader EJ25 turbo family. The Subaru EJ25 engine (our listing) covers the broader EJ25 family with turbo and non-turbo variants. The Subaru WRX engines (our listing) provides WRX engine overview context. The Cosworth EJ257 (this listing) represents the highest-tier performance variant of the EJ257 family available, with motorsport engineering content that distinguishes it from stock and lower-tier rebuilt EJ257 engines.
Vehicle Compatibility
| Build Level | HP Range | Torque Range | Notes |
|---|---|---|---|
| Cosworth Stage 1 | 320-340 HP | 310-325 lb-ft | Bolt-on package, forged internals, mild tuning |
| Cosworth Stage 2 | 340-360 HP | 325-340 lb-ft | More aggressive tuning, larger turbo |
| Cosworth Stage 2.5 | 360-380 HP | 340-360 lb-ft | CNC heads, larger turbocharger |
| Cosworth Stage 3 | 400-450 HP | 360-400 lb-ft | Race-oriented, requires race fuel |
| Cosworth Race Builds | 500-600+ HP | 400-500+ lb-ft | Track and rally builds, complete engine package |
Cosworth EJ257 Specifications and Cosworth Upgrades
| Vehicle | Years | Chassis Code | Notes |
|---|---|---|---|
| Subaru WRX STI (GD chassis) | 2004-2007 | GD | The original US WRX STI, 305 HP stock |
| Subaru WRX STI (GR/GV chassis) | 2008-2014 | GR (hatch) / GV (sedan) | Second-generation US WRX STI |
| Subaru WRX STI (VA chassis) | 2015-2021 | VA | Third-generation US WRX STI, final EJ257 production |
Stock EJ257 vs Cosworth EJ257 Comparison
| Feature | Stock EJ257 (WRX STI) | Cosworth EJ257 |
|---|---|---|
| HP (Stock Tune) | 305 HP | 330-350 HP |
| Torque | 290 lb-ft | 330-340 lb-ft |
| Block Design | Open-deck (weak under high boost) | Closed-deck (stronger) |
| Connecting Rods | Cast (limits to ~400 HP safe) | Forged H-beam (600+ HP capable) |
| Pistons | Cast (ringland failures common) | Forged (much stronger) |
| Crankshaft | Cast | Forged |
| Head Gaskets | Stock single-layer | Multi-layer steel |
| Power Potential | ~400 HP safe ceiling | 500-700+ HP achievable |
| Cost | $5,000-8,000 used | $4,999-9,500 used (this listing) / $12,000+ new |
Common Maintenance and Service Reference
| Vehicle | Compatibility |
|---|---|
| Subaru WRX STI (1st gen US, GD chassis) | 2004-2007 with EJ257 turbo |
| Subaru WRX STI (2nd gen US, GR hatch / GV sedan) | 2008-2014 with EJ257 turbo |
| Subaru WRX STI (3rd gen US, VA chassis) | 2015-2021 with EJ257 turbo |
| Performance Swap Builds | Forester XT, Legacy GT, Impreza performance builds (with appropriate ECU and supporting modifications) |
Why Buy From Part Nests
- Engine verified as Cosworth-built EJ257 (legendary British motorsport engineering firm Cosworth-engineered Subaru EJ257 crate)
- Cosworth specification documented (Cosworth-developed pistons, rods, crankshaft, head work, oil system, balanced rotating assembly)
- Application confirmed (Subaru WRX STI performance builds, custom Subaru projects, race / track day applications, stage upgrade builds)
- Horsepower potential documented (Cosworth-built EJ257 typically supports 450-700 plus HP capability)
- Internals verified (Cosworth forged pistons, H-beam rods, balanced crankshaft, ARP fasteners)
- Both cylinder heads condition documented (CNC-ported / flowed in Cosworth specification)
- Cosworth oil system verified (high-volume oil pump, baffled oil pan, oil cooler provisions)
- Specialty freight handling for crate engine to all 50 states
- 15 day replacement warranty on internal defects
- Subaru-experienced support team familiar with Cosworth EJ257 / stock EJ257 differences and performance Subaru applications
- Call (855) 634-4447 to confirm the correct part for your build before ordering.
15 Day Replacement Warranty
Every Cosworth EJ257 crate engine purchased through Part Nests carries a 15 day replacement warranty starting on the delivery date. Crate engines are sold with the understanding that proper supporting modifications (turbo, fuel system, ECU tuning, cooling, etc.) are required to safely operate at Cosworth-rated power levels.
What Is Covered
- Internal defects already present when the engine arrives
- Cosworth piston defects within 15 days from installation
- Cosworth H-beam connecting rod defects within 15 days from installation
- Crankshaft defects within 15 days from installation
- Cylinder head crack failures within 15 days from installation (both heads)
- Block crack failures within 15 days from installation
- Cosworth oil system component defects within 15 days from installation
- ARP fastener defects within 15 days from installation
- Cylinder head valve / valve spring / retainer defects within 15 days from installation
What Is Not Covered
- Damage caused during installation
- Damage from operation beyond Cosworth-rated power levels without supporting modifications
- Damage from incorrect engine oil (Cosworth specifies premium synthetic motorsport-grade oil)
- Damage from inadequate fuel system (Cosworth power capability requires upgraded injectors, fuel pump, fuel rails as needed)
- Damage from inadequate ECU tuning (proper standalone or professionally-tuned ECU calibration is required for Cosworth power capability)
- Damage from inadequate cooling system (Cosworth high-power operation requires upgraded cooling capacity)
- Damage from inadequate turbocharger sizing (Cosworth power capability requires properly-sized turbocharger)
- Damage from detonation, lean conditions, or other tuning errors (proper professional ECU tuning is essential)
- External components (intake manifold, exhaust manifolds, turbocharger if not supplied, ECU and wiring harness, accessory drive, transmission, AC compressor, alternator, starter, fuel tank, fuel lines outside engine) unless itemized
- Labor expenses of any kind
To start a warranty claim, reach us within 15 days of delivery at (855) 634-4447.
- Cosworth-Engineered Build: Legendary British motorsport firm specification
- Cosworth Forged Pistons: Specific compression ratio, ring pack, and cooling features
- Cosworth H-Beam Connecting Rods: Higher tensile strength than stock rods
- Balanced Rotating Assembly: Motorsport tolerance balancing
- ARP Main and Head Studs: Premium aftermarket fastener brand
- CNC-Ported Cylinder Heads: Cosworth CNC port and flow work
- Cosworth Oil System: High-volume pump, baffled pan, cooler provisions
- 15 Day Replacement Cover: Internal defects protected from delivery onward
Additional information
| Brand | Subaru |
|---|---|
| engine-type | Flat-4 (horizontally opposed boxer), turbocharged, DOHC |
| engine-family | Subaru EJ-series, Cosworth performance build |
| manufacturer-base | Subaru Corporation |
| manufacturer-build | Cosworth |
| configuration | Flat-4 horizontally opposed boxer (NOT inline-4) |
| displacement | 2.5L (2, 457 cc) |
| bore-x-stroke | 99.5 mm x 79.0 mm |
| hp | 330-350 HP (vs stock 305 HP) |
| torque | 330-340 lb-ft (vs stock 290 lb-ft) |
| compression | 8.2-8.4:1 |
| aspiration | Turbocharged with intercooler |
| fuel-system | Sequential multi-port injection (upgraded injectors typical) |
| fuel-type | Premium 91 octane minimum, 93 recommended |
| valvetrain | DOHC per bank, 16 valves, AVCS intake + exhaust |
| block-material | Closed-deck aluminum (Cosworth upgrade vs stock open-deck) |
| crankshaft | Forged (Cosworth) |
| connecting-rods | Forged H-beam (Cosworth) |
| pistons | Forged (Cosworth) |
| head-gaskets | Multi-layer steel (Cosworth) |
Cosworth-built Subaru EJ257 2.5L turbo boxer-4 with motorsport engineering. The Cosworth EJ257 is an OEM-pattern Cosworth-built Subaru EJ257 crate engine for high-performance Subaru WRX STI builds and custom Subaru projects. Cosworth is the legendary British motorsport engineering firm with motorsport heritage spanning Formula 1, IndyCar, World Rally Championship, and decades of engine development for premium performance applications. The Cosworth EJ257 represents Cosworth's engineering applied to Subaru's EJ257 2.5L turbo boxer-4 (the STI variant per our listing and the broader EJ25 family), with Cosworth-developed pistons, connecting rods, crankshaft balancing, cylinder head work, oil system, and supporting upgrades. Cosworth EJ257 crate engines typically support 450-700 plus HP capability with proper supporting modifications (turbo, fuel system, ECU, cooling, etc.).
Substantial upgrades across pistons, rods, crankshaft, heads, oil system, and fasteners. The Cosworth EJ257 is a substantially upgraded version of the stock Subaru EJ257 (per our listing). Key Cosworth upgrades: forged pistons with specific compression ratio, ring pack, and cooling features (stock EJ257 uses cast pistons in some applications); H-beam connecting rods Cosworth-spec forged with higher tensile strength than stock rods; balanced rotating assembly with Cosworth-balanced crankshaft, rods, and pistons assembled and balanced to motorsport tolerances; ARP main and head studs (premium aftermarket fastener brand); CNC-ported cylinder heads with Cosworth CNC port and flow work for improved breathing; valvetrain upgrades depending on specific build level; oil system upgrades including high-volume oil pump, baffled oil pan, oil cooler provisions; block preparation honed, decked, and machined to Cosworth tolerances.
Legendary British motorsport engineering firm with F1, IndyCar, and WRC heritage. Cosworth is one of the most legendary names in motorsport engineering. Formula 1 heritage: Cosworth's DFV V8 powered Formula 1 from 1967 through the 1980s, winning more F1 races than any other engine in history. IndyCar / CART heritage: Cosworth-built engines powered IndyCar / CART racing for decades. World Rally Championship: Cosworth Engineering was Subaru's WRC engine partner during Subaru's most successful rally years (the Subaru / Cosworth WRC partnership produced the engines that defined Subaru rally heritage). Aftermarket performance: Cosworth aftermarket performance components are premium-positioned in the Subaru WRX / STI performance community. British engineering: Cosworth's UK-based engineering and manufacturing maintains motorsport quality standards.
450-700 plus HP capability with proper supporting modifications. Cosworth EJ257 crate engines typically support 450-700 plus HP capability with proper supporting modifications. Supporting modifications required to achieve this power capability safely: properly-sized turbocharger (the stock IHI VF-series turbo is the limiting factor at higher power levels), upgraded fuel system (high-flow injectors, fuel pump, fuel rails as needed), professional ECU tuning (standalone ECU or professionally-tuned stock ECU calibration), upgraded cooling system (larger radiator, intercooler, oil cooler for sustained high-power operation), upgraded intake and exhaust system, upgraded clutch and drivetrain (the stock STI clutch is the limiting factor at higher power levels). Without proper supporting modifications, the Cosworth-rated power capability cannot be safely achieved. The stock EJ257 by comparison typically supports approximately 300-400 HP with supporting modifications.
Performance Subaru builds across track, rally, and custom applications. Performance Subaru STI builds: owners building 450-700 plus HP STI applications use Cosworth EJ257 as the foundation engine. Track day / time attack applications: Cosworth engines withstand sustained high-RPM operation common in track use. Rally / rallycross applications: the Cosworth EJ257 heritage from Subaru WRC partnership makes it a natural choice for rally builds. Custom Subaru projects: engine swap projects, restomod builds, and other custom Subaru applications. Stage upgrade builds: owners upgrading from stock EJ257 to support higher power often choose Cosworth as the upgrade engine. The Cosworth EJ257 represents the highest-tier performance variant of the EJ257 family available, with motorsport engineering content that distinguishes it from stock and lower-tier rebuilt EJ257 engines.
Multiple Subaru engines across batches 29-30 with Cosworth as premium tier. The Cosworth EJ257 crate engine (this listing) is the premium Cosworth-built Subaru EJ257 crate engine for performance applications. The Subaru EJ257 engine covers the stock OEM EJ257 STI engine; the Cosworth EJ257 is the upgraded performance variant of that base engine. The Subaru EJ255 engine is the related lower-output WRX turbo variant. The Subaru EJ25 Turbo engine covers the broader EJ25 turbo family. The Subaru EJ25 engine from covers the broader EJ25 family with turbo and non-turbo variants. The Subaru WRX engines provides WRX engine overview context. The Cosworth EJ257 represents the highest-tier performance variant available.
Premium synthetic oil, professional ECU tune, supporting modifications. After acquiring a Cosworth EJ257 crate engine, budget for these items. Premium synthetic motorsport-grade oil: Cosworth specifies premium synthetic oil; budget premium oil costs for proper maintenance. Professional ECU tuning: budget $500-2,000 for professional tuning at qualified Subaru / Cosworth-experienced tuner; standalone ECU adds substantial additional cost. Supporting modifications budget: turbocharger upgrade $2,500-7,500 (the stock VF turbo is the limiting factor), fuel system upgrade $1,500-3,500 (high-flow injectors, fuel pump, fuel rails), cooling system upgrade $1,500-4,000 (larger radiator, intercooler, oil cooler), upgraded clutch and drivetrain $1,500-5,000 (stock STI clutch limiting factor at higher power). Short oil change intervals: 2,500-3,750 miles for sustained high-power operation. Strictly proper 91+ octane fuel; ethanol blends (E85) for highest power capability. Properly-trained installer / mechanic familiar with Cosworth specification.
No. There is no core return required.
2 reviews for Cosworth EJ257 Crate Engine for Sale | Legendary Cosworth Engineering Built
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Augustus K. –
Bought for my Cosworth EJ257 Crate Engine. Second time using Part Nests, still solid.
Magdalena S. –
Right fit for the Cosworth EJ257 Crate Engine. Rep knew what they were talking about.