1. Engine Crankshafts Products
  2. sku: 19582433741972722
  3. MOLNAR S830EJ25

MOLNAR TECHNOLOGIES S830EJ25 Forged Crankshaft 83MM

fits make: Subaru.

S830ej25 Molnar Technologies Subaru Forged Crankshaft 83mm Stroke Ej25

( Brand: Molnar Technologies ), ( Manufacturer Part Number: S830EJ25 ), ( Part Type: Crankshaft ), ( Performance Part: Yes )

Review MOLNAR TECHNOLOGIES Subaru Forged Crankshaft 83mm Stroke fits EJ25

The **Molnar S830EJ25 83mm Forged Crankshaft** is a meticulously engineered, high-performance component designed exclusively for Subaru s legendary **EJ25** inline-four engine, offering a substantial boost in power, torque, and reliability for both street and track applications. Crafted from **7075-T6 aluminum alloy**, this crankshaft is forged using advanced **vacuum-assisted casting and precision machining** to achieve an exceptional strength-to-weight ratio, reducing reciprocating mass while maintaining uncompromising durability. The **83mm stroke** a significant increase from the stock 78mm delivers a **nearly 6% larger displacement**, translating into a more linear powerband, higher low-end torque, and a noticeable surge in horsepower and revving potential. Each journal and main bearing surface is **honed to precise tolerances** and **hard anodized** for superior wear resistance, ensuring longevity even under extreme stress, whether in high-RPM drag racing, aggressive daily driving, or endurance racing scenarios.

The **S830EJ25** features **optimized counterweights** that minimize vibration and enhance balance, reducing engine harmonics that can lead to premature wear on critical components like rods, bearings, and the block itself. The **integrated oil passages** are strategically placed to improve lubrication flow, particularly under high-stress conditions, while the **precision-machined rod journals** are designed to accommodate aftermarket connecting rods, allowing for further tuning flexibility. This crankshaft is not merely an upgrade it s a **performance catalyst**, enabling builders to push the EJ25 engine beyond its stock limitations while maintaining structural integrity. Whether paired with a **turbocharged setup, nitrous injection, or a supercharger**, the **Molnar S830EJ25** provides the foundational strength needed to handle the increased loads without sacrificing reliability.

Ideal for **high-performance builds, engine swaps, or restoration projects**, this crankshaft is backed by **Molnar s reputation for precision engineering and durability**, making it a trusted choice among tuners, racers, and enthusiasts who demand the best from their Subaru engines. The **83mm stroke** also enhances the EJ25 s natural breathing characteristics, allowing for better cylinder filling and improved efficiency whether under boost or naturally aspirated. With its **forged construction, refined balancing, and meticulous attention to detail**, the **Molnar S830EJ25** is the ultimate upgrade for those seeking to unlock the full potential of the EJ25 platform while ensuring a smooth, reliable, and high-revving power delivery.

### **Pros and Cons of Buying a Molnar S830EJ25 Subaru Forged Crankshaft (83mm, EJ25 Engine)**

#### **Pros:**

1. **Increased Power and Torque** The 83mm stroke is larger than the stock EJ25 crank (78mm), which directly increases displacement and potential power output. This is particularly beneficial for forced induction builds (turbo/supercharger) or high-RPM applications.

2. **Durability and Strength** Molnar cranks are forged from high-quality steel, making them significantly stronger than cast cranks. This reduces the risk of catastrophic failure under heavy loads, especially in aggressive builds.

3. **Better Compression Ratio Tolerance** A larger stroke allows for higher compression ratios without excessive piston-to-valve clearance issues, which is useful for naturally aspirated or mildly forced builds.

4. **Compatibility with Stock Components** The 83mm stroke is a common upgrade for EJ25 engines, meaning many aftermarket parts (rods, pistons, bearings) are designed to work with it without major modifications.

5. **Improved Low-End Torque** The longer stroke generally provides better low-end torque, which can improve drivability in daily driving or towing applications.

6. **Aftermarket Support** The EJ25 platform has a strong aftermarket presence, and the 83mm stroke is a well-documented upgrade, making it easier to find supporting parts and tuning advice.

7. **Potential for Big Bore Kits** If you plan to go further with a big bore kit (e.g., 86mm or 88mm), a 83mm crank is a logical intermediate step before jumping to a larger bore.

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#### **Cons:**

1. **Cost** A Molnar forged crank is significantly more expensive than a stock or aftermarket cast crank. The price can range from **$1,200 to $1,800 **, depending on the dealer and additional components (rods, bearings, etc.).

2. **Weight** Forged cranks are heavier than cast ones, which can slightly reduce engine responsiveness, especially in high-revving applications. However, the weight difference is minimal compared to the strength benefits.

3. **Installation Complexity** Swapping a crank requires a full engine teardown, balancing, and reassembly. This is a labor-intensive process that may require professional help, adding to the overall cost.

4. **Potential for Overkill** If you re only planning a mild build (e.g., stock or low-power turbo), the extra strength of a forged crank may not be necessary. A high-quality aftermarket cast crank (e.g., JE or Molnar s lower-end options) could suffice at a fraction of the cost.

5. **Limited Stock Compatibility** Some stock components (e.g., oil pump, timing chain) may need upgrading to handle the increased stress of a forged crank and larger stroke. This adds to the overall build cost.

6. **Balancing and Tuning Required** After installation, the engine will need balancing and proper tuning to ensure smooth operation, especially with a larger stroke and potential power increases.

7. **Resale Value Impact** While a forged crank improves the engine s longevity, it may not significantly boost resale value, as most buyers prioritize reliability and cost over exotic components.

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### **Ending Conclusion:**

The **Molnar S830EJ25 forged crankshaft (83mm stroke) is an excellent choice** for serious EJ25 builders who plan to push their engines with forced induction, high compression, or aggressive power goals. Its superior strength, durability, and torque characteristics make it a worthwhile investment for those who want a long-term, high-performance solution.

However, if you re on a budget or only planning a mild build, a **high-quality aftermarket cast crank (e.g., JE or Molnar s entry-level forged options)** may be a more practical choice. The decision ultimately depends on your power goals, budget, and whether you prioritize reliability over cost.

### **Recommendation:** - **Buy it if:**

- You re building a **turbocharged or supercharged EJ25** with significant power goals (350 hp).

- You want **maximum durability** for high-RPM or aggressive builds.

- You plan to **increase displacement further** (e.g., with a big bore kit).

- You re willing to invest in a **premium, long-term solution** rather than a budget-friendly option.

- **Skip it if:**

- You re on a **tight budget** and only need a mild upgrade.

- Your build is **stock or low-power** (250-300 hp), where a cast crank would suffice.

- You prefer **minimal engine modifications** and don t want the hassle of a full crank swap.

For most **serious EJ25 turbo builds**, the **Molnar S830 is a strong recommendation** it s the best balance of strength, performance, and longevity for high-stress applications. However, weigh the cost against your specific goals before committing.

Details:

Manufacturer: Molnar Technologies. Crankshaft - 83mm Stroke Internal Balance Billet Steel 1-Piece Seal Subaru EJ-Series Each. Part Number: S830EJ25.

part #: s830ej25 prices

  • $2101.82-$2196.76

specifications cranshafengin:

  • for makes: Subaru
  • brand: Molnar Technologies
  • mpn: S830ej25
  • part type: Crankshaft
  • performance part: Yes

general cranshafengin:

  • condition: New
  • Car Truck Parts Accessories > Engines Engine Parts > Crankshafts

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  • transit: 2-5 Days
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  • service: Standard
  • type: Fixed
  • class: Standard

offer cranshafengin:

  • availability: In Stock
  • started: March 30, 2026
  • quantity: 1
  • sold: 0
  • options: Ship-to-home

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  • policy: Returns Accepted
  • time: 30 Days
  • paid by: Seller

seller cranshafengin:

  • rating: 99.8%
  • # reviews: 125766
  • city: San Leandro, California
for makes: subaru, part type: crankshaft, performance part: yes,
category: auto parts > car truck parts accessories > engines engine parts > crankshafts, sku: 19582433741972722,
Molnar Technologies S830EJ25 Is Similar To:
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2 offers $2101.82–$2196.76 USD
  • New. Offer #1 priced at $2101.82 + $0.00 shipping estimate = $2101.82* total. Crankshaft - 83 mm Stroke - Internal Balance - Billet Steel - 1-Piece Seal - Subaru EJ-Series - Each. Part Number: .FREE SHIPPING
  • New. Offer #2 priced at $2196.76 + $0.00 shipping estimate = $2196.76* total. If a defect is identified after this period, it will fall under the manufacturer's warranty and should be handled directly with them. Manufacturer Part Number: .FREE SHIPPING

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