1. Pistons, Rings, Rods & Parts Engines Components For Sale
  2. sku: 12374445125151741
  3. MAXPEEDINGRODS M4F0BO

MAXPEEDINGRODS M4F0BO Beam Forged Connecting Rods EJ20/22/25 89-2009

fits model: Sti, Impreza, Legacy. make: Subaru.

M4f0bo Maxpeedingrods H-beam Forged Connecting Rods For Subaru Impreza Sti Ej20/22/25 Legacy 89-2009

( Brand: Maxpeedingrods ), ( Manufacturer Part Number: M4F0BO ), ( Part Type: Rod ), ( Big End Diameter: 55mm/2.165 ), ( Big End Width: 21.38mm/0.840 ), ( California Prop 65 Warning: California Prop 65 Warning ), ( Fit For: For Subaru Ej18 Ej20 Ej22 Ej25 Ej207 Ej257 Sti ), ( Fitment Type: Performance/custom ), ( Fits: 02-05 For Subaru Impreza Sti Forester Legacy 2.0l Ej205 ), ( Ipn: 02-05 ), ( Material: Titanizing 4340 Aircraft Chrome Moly Quality Steel ), ( Note: No Instruction Included ), ( Notice: This Is Aftermarket Replcement Part ), ( Pin Type: Bronzed Bushing Floating Pin ), ( Quality: Forged Rods With Tuv Certification ), ( Quantity: Set Of 4 Pieces ), ( Rod Length: 130.5mm/5.137 ), ( Small End Diameter: 23mm/0.905 ), ( Surface Finish: Brand New ), ( Weight Tolerance: Balanced To / 1 Gram In Set )

Review MAXPEEDINGRODS H beam Forged Connecting Rods Subaru Ej20/22/25 89-2009 fits IMPREZA LEGACY STI

The **MaxpeedingRods M4F0BO H-Beam Forged Connecting Rods** represent the pinnacle of performance engineering for Subaru s legendary **EJ20/EJ22/EJ25** inline-four engines, spanning models from the **1989 to 2009 Impreza STI** and its high-performance derivatives. Designed with precision and built to endure the most demanding conditions, these rods are a testament to MaxpeedingRods commitment to durability, strength, and reliability critical factors for enthusiasts pushing their STI beyond factory limits. Crafted from **high-grade 4340 alloy steel**, these rods undergo a **multi-stage forging process**, ensuring a refined grain structure that maximizes fatigue resistance and load-bearing capacity. The **H-beam design** is not merely aesthetic; it distributes stress more evenly across the rod s cross-section, reducing bending and torsional fatigue while maintaining rigidity under extreme power outputs. This architecture is particularly advantageous for high-revving applications, where traditional I-beam rods may succumb to premature failure due to stress concentrations.

Each rod is **fully machined from solid billet**, eliminating the weaknesses inherent in cast components and ensuring consistent dimensional accuracy. The **precision-ground rod journals** and **crankpin interfaces** feature a **mirror-finish polish**, reducing friction and wear while accommodating high-performance bearings with ease. The **7.0mm rod bolt holes** are strategically positioned to optimize weight distribution and torsional stiffness, a critical consideration for engines running forced induction or aggressive camshaft profiles. To further enhance performance, the rods are **shot-peened** to induce compressive residual stresses on the surface, significantly improving fatigue life and resistance to crack propagation an essential safeguard for engines operating at elevated RPMs or under heavy loads.

Beyond their mechanical superiority, these rods are engineered with **installation convenience** in mind. The **pre-drilled and tapped rod bolt holes** eliminate the need for custom machining, while the **pre-marked rod numbering** simplifies assembly, ensuring proper alignment with the crankshaft and pistons. Compatible with a wide range of **EJ20/EJ22/EJ25** engines including naturally aspirated, turbocharged, and supercharged variants they seamlessly integrate with aftermarket components like **big-bore kits, high-lift cams, or aggressive tuning setups**. Whether you re chasing **street performance, track dominance, or reliability at extreme power levels**, these rods deliver the structural integrity and performance edge required to push your Subaru STI to its limits without compromising longevity.

For the discerning builder, the **M4F0BO H-Beam Forged Connecting Rods** are more than an upgrade they are a **foundation for building an engine that will outlast its expectations**. Backed by MaxpeedingRods reputation for quality and supported by rigorous testing, these rods are the ideal choice for those who demand nothing less than **uncompromising strength and precision** in their high-performance Subaru.

The Maxpeedingrods M4F0BO H-Beam Forged Connecting Rods are a high-performance aftermarket option designed for Subaru Impreza STI models with the EJ20/EJ22/EJ25 engines (1989 2009). Below is a detailed breakdown of their pros and cons, followed by a conclusion and recommendation.

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**Pros:**

1. **Enhanced Strength and Durability**

The forged H-beam design is significantly stronger than stock cast rods, reducing the risk of catastrophic failure under high stress. Forged rods are less prone to fatigue cracking, which is critical for engines running at higher RPMs, boost levels, or with aggressive tuning.

2. **Improved Weight Distribution**

The H-beam shape provides better weight distribution compared to traditional I-beam or D-beam designs, which can improve engine balance and reduce vibrations. This is particularly beneficial for naturally aspirated or forced induction setups where engine speeds are elevated.

3. **Compatibility with High-Performance Modifications**

These rods are designed to support aggressive builds, including turbocharging, nitrous, or high-revving camshafts. They are often paired with other Maxpeedingrods components (e.g., pistons, crankshafts), creating a cohesive high-performance package.

4. **Reputation for Quality**

Maxpeedingrods is a well-regarded brand in the aftermarket, known for precision machining and attention to detail. Their rods undergo rigorous testing, including X-ray inspection and load testing, to ensure reliability.

5. **Potential for Increased Power Output**

By reducing the risk of rod failure, these rods allow for more aggressive tuning without compromising safety. This can translate to higher horsepower and torque, especially when paired with other performance upgrades.

6. **Warranty and Support**

Maxpeedingrods offers warranties on their products, and their customer support is often praised for responsiveness. This can be reassuring for buyers investing in high-cost performance parts.

7. **Custom Fitment Options**

The M4F0BO rods are designed specifically for the EJ20/22/25 engines, with precise fitment to minimize clearance issues. This reduces the need for extensive machining or modifications to the engine block.

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**Cons:**

1. **High Cost**

Forged connecting rods are significantly more expensive than stock or aftermarket cast rods. The M4F0BO rods are no exception, often costing several hundred dollars each. This makes them a substantial investment, especially for enthusiasts on a budget.

2. **Installation Complexity**

Installing forged rods requires careful attention to detail, including proper gasket surfaces, rod bolt torque specifications, and alignment. Improper installation can lead to premature wear or failure. This may necessitate professional installation, adding to the overall cost.

3. **Potential for Overkill**

For stock or mildly tuned EJ engines, the benefits of forged rods may not be immediately noticeable. If the engine is not heavily modified or stressed, the cost may not be justified. Forged rods are best suited for high-revving, boosted, or heavily modified engines.

4. **Limited Availability of Spare Parts**

While Maxpeedingrods rods are durable, if a failure occurs (though rare), finding replacement rods or matching components may be more difficult than with stock or more common aftermarket parts.

5. **Compatibility with Stock Components**

Forged rods often require complementary upgrades, such as a stronger crankshaft, high-performance pistons, and upgraded rod bolts. Skipping these can negate the benefits of the rods and may lead to premature failure of other components.

6. **Time-Consuming Build Process**

Upgrading to forged rods typically involves a full engine rebuild or at least a rod changeout, which can be time-consuming and labor-intensive. This may require removing the engine from the vehicle and performing additional work (e.g., machining rod journals, replacing gaskets).

7. **Potential for Resale Value Concerns**

While high-performance parts can increase the value of a modified vehicle, forged rods may not always translate to a proportional increase in resale value, especially if the market for heavily modified STIs is niche.

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**Conclusion:**

The Maxpeedingrods M4F0BO H-Beam Forged Connecting Rods are an excellent choice for Subaru EJ20/22/25 engine owners who are pursuing high-performance builds, including turbocharging, nitrous, or aggressive tuning. Their strength, durability, and compatibility with other Maxpeedingrods components make them a top-tier option for those willing to invest in a reliable and high-revving engine. However, the high cost, installation complexity, and potential overkill for stock or mildly modified engines must be carefully considered.

For enthusiasts who are committed to pushing their STI s limits whether for track use, high-RPM naturally aspirated applications, or forced induction the M4F0BO rods are a worthwhile upgrade. For those with less aggressive plans or tighter budgets, the benefits may not justify the expense, and alternative options (e.g., high-quality cast rods or stock rods with complementary upgrades) could be more practical.

---

**Recommendation:** - **Proceed with the M4F0BO rods if:**

- You are building a high-performance EJ engine with turbocharging, nitrous, or aggressive camshafts.

- You are willing to invest in a full engine support package (e.g., crankshaft, pistons, rod bolts, and gaskets).

- You have the budget and technical expertise (or access to a professional mechanic) to handle installation and maintenance.

- Your primary goal is reliability and longevity under extreme stress.

- **Consider alternatives if:**

- Your engine is stock or only mildly modified, and you are not pushing it to high RPMs or boost levels.

- You are looking for a more budget-friendly option (e.g., high-quality aftermarket cast rods or stock rods with upgraded bolts).

- You lack the time, tools, or mechanical skill to properly install and maintain forged rods.

Ultimately, the M4F0BO rods are a premium choice for serious STI builders, but they are not necessary for every application. Carefully assess your goals, budget, and engine modifications before making a decision.

Details:

Each rod is magnetic particle tested to ensure free of flaws. 9.High precision CNC machined,Precision rod cap alignment dowels. Manufacturer. Quick, Simple.

Titanizing can further improve the bending strength of product: Always the correct part. Fast Shipping. The density of titanium is significantly lower than that steel, while maintaining considerable strength, which means it lighter but the strength very similar.

G guaranteed Fitment. H-Beam Forged Connecting Rods for Subaru Impreza STI EJ20/22/25 Legacy 89-2009. H-Beam design reduces weight without compromising strength. Advertised Horsepower Rating:200HP/piece, Top acceleration: 9000rpm, package size 28CM 21CM 10CM.

For Subaru Impreza WRX STI EJ20 EJ22 EJ25 Engine, Legacy Forester 2.0L Turbo EJ205 Engine 2002 - 2005, STi EJ207 1998 -present, 2.5L EJ255 2006 -2014, EJ257 2004 -2016, Saab 9-2X 2005 - 2006, Isuzu Asoka 1990 -1993, 1989 -2009, SF series 1997 - 2002 , XT 2004 -2013, Outback 2005, 2007 -2009, Impreza 95-01, 95-96, Pin Type: Floating Piston.

part #: m4f0bo price

  • $232.00

specifications pistonrinro:

  • for models: Sti, Impreza, Legacy
  • for makes: Subaru
  • brand: Maxpeedingrods
  • mpn: M4f0bo
  • part type: Rod
  • big end diameter: 55mm/2.165
  • big end width: 21.38mm/0.840
  • california prop 65 warning: California Prop 65 Warning
  • fit for: For Subaru Ej18 Ej20 Ej22 Ej25 Ej207 Ej257 Sti
  • fitment type: Performance/custom
  • fits: 02-05 For Subaru Impreza Sti Forester Legacy 2.0l Ej205
  • ipn: 02-05
  • material: Titanizing 4340 Aircraft Chrome Moly Quality Steel
  • note: No Instruction Included
  • notice: This Is Aftermarket Replcement Part
  • pin type: Bronzed Bushing Floating Pin
  • quality: Forged Rods With Tuv Certification
  • quantity: Set Of 4 Pieces
  • rod length: 130.5mm/5.137
  • small end diameter: 23mm/0.905
  • surface finish: Brand New
  • weight tolerance: Balanced To / 1 Gram In Set

general pistonrinro:

  • condition: New
  • Car Truck Parts Accessories > Engines Engine Parts > Connecting Rods Parts

returns pistonrinro:

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

shipping pistonrinro:

  • carrier: FedEx
  • type: Fixed
  • class: Standard
  • cost: $0.00
  • service: FedEx Ground / FedEx Home Delivery
  • transit: 5-8 Days

payments pistonrinro:

  • other
  • credit card: Discover
  • wallet: Apple-pay

offer pistonrinro:

  • started: February 13, 2026
  • sold: 0
  • options: Ship-to-home
  • best offers: True
  • availability: In Stock
  • quantity: 2

seller pistonrinro:

  • # reviews: 782
  • city: Rowland height, California
  • rating: 99.5%
for models: sti, impreza, legacy, for makes: subaru, part type: rod, big end diameter: 55mm/2.165, big end width: 21.38mm/0.840, california prop 65 warning: california prop 65 warning, fit for: for subaru ej18 ej20 ej22 ej25 ej207 ej257 sti, fitment type: performance/custom, fits: 02-05 for subaru impreza sti forester legacy 2.0l ej205, note: no instruction included, notice: this is aftermarket replcement part, pin type: bronzed bushing floating pin, quality: forged rods with tuv certification, quantity: set of 4 pieces, rod length: 130.5mm/5.137, small end diameter: 23mm/0.905, surface finish: brand new, weight tolerance: balanced to / 1 gram in set,
category: auto parts > car truck parts accessories > engines engine parts > connecting rods parts, material: titanizing 4340 aircraft chrome moly quality steel, sku: 12374445125151741,
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1 offer $232.00 USD
  • New other (see details). Offer #1 priced at $232.00 + $20.00 shipping estimate = $252.00* total. Forged 4340 steel. Item: MaxpeedingRods Forged Connecting Rods.+$20.00 shipping

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