RADIUM 20-0449 Acv Block 13B-REW

( Brand: Radium ), ( Manufacturer Part Number: 20-0449 ), ( Part Type: Block )

Review RADIUM Acv Block off Mazda

The **Radium 20-0449 ACV Block-Off for Mazda 13B (Rew)** is a precision-engineered, high-performance accessory designed to enhance the functionality and longevity of your vehicle s cooling system while maintaining optimal engine performance. Crafted from durable, corrosion-resistant materials, this block-off plate is specifically tailored to fit Mazda models with the 13B engine family, including the iconic RX-7, Miata (NA), and other applications requiring a reliable solution for air conditioning (AC) system modifications or maintenance. The ACV (Air Conditioning Valve) block-off serves as a critical component for drivers who wish to disable the factory AC compressor clutch, either to reduce parasitic drag on the serpentine belt system, improve fuel efficiency, or simplify maintenance by eliminating the need for periodic AC system servicing. Constructed with a robust, heat-treated metal frame and reinforced mounting points, this block-off ensures a secure and vibration-free installation, preventing any potential leaks or misalignments that could compromise engine performance. Its compact yet sturdy design allows for easy integration into the engine bay without requiring extensive modifications, making it an ideal choice for both DIY enthusiasts and professional mechanics. Whether you're seeking a temporary solution for off-road adventures, a permanent upgrade for daily driving, or a straightforward way to bypass a malfunctioning AC system, the Radium 20-0449 offers a dependable, long-lasting performance that aligns with the demands of modern high-performance and practical applications. Built to withstand the rigors of daily use and extreme conditions, this block-off is a testament to Radium s commitment to quality, ensuring that your Mazda s engine remains protected and your driving experience remains optimized.

The **Radium 20-0449 ACV Block-Off** is designed to replace the stock ACV (Air Conditioning Vacuum) block on the **Mazda 13B engine** (commonly found in models like the 1993 1998 Mazda Miata/NA). Below is a detailed breakdown of its pros and cons, followed by a conclusion and recommendation.

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### **Pros of the Radium 20-0449 ACV Block-Off**

1. **Improved Cooling Efficiency**

The stock ACV block can restrict airflow to the radiator, especially under heavy loads or in high-temperature conditions. The Radium block-off removes this restriction, allowing cooler air to flow directly to the radiator, which can improve cooling performance and reduce engine temperatures.

2. **Better Performance Under Load**

By eliminating the vacuum-operated ACV, the engine can maintain optimal airflow to the radiator even when the AC is engaged or during high-speed driving. This can help prevent overheating in performance applications, such as when running a turbocharger, forced induction, or high-compression modifications.

3. **Simplified System**

The ACV block-off removes a potential failure point in the cooling system. The stock ACV can fail (sticking open or closed), leading to overheating or poor cooling. Replacing it with a block-off eliminates this risk entirely.

4. **Compatibility with Aftermarket Upgrades**

If you plan to install a larger radiator, upgraded fans, or other cooling modifications, the Radium block-off ensures that these upgrades work optimally without interference from the stock ACV.

5. **Easy Installation**

The Radium block-off is a straightforward bolt-on replacement. It requires minimal tools and can be installed in under an hour, even for a beginner mechanic. No modifications to the engine bay are typically needed.

6. **Cost-Effective**

Compared to other cooling upgrades (e.g., upgraded radiators or fans), the Radium block-off is relatively inexpensive. It provides noticeable benefits without a significant investment.

7. **Reduced Drag**

The stock ACV can create slight airflow resistance when it s open. The block-off removes this minor drag, which may contribute to marginal improvements in fuel efficiency or throttle response in some cases.

8. **No Risk of Vacuum Leaks**

The stock ACV relies on vacuum from the engine to operate. If the vacuum line develops a leak or the ACV fails, it can lead to poor cooling or engine overheating. The block-off eliminates this concern entirely.

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### **Cons of the Radium 20-0449 ACV Block-Off**

1. **Loss of Original ACV Functionality**

The stock ACV is designed to regulate airflow to the radiator based on engine vacuum. When the AC is on or under certain conditions, it can restrict airflow to prevent the engine from overheating. The block-off removes this regulation, meaning the radiator will always receive maximum airflow, which may not be ideal in all scenarios (e.g., very hot climates or high-altitude driving).

2. **Potential for Overcooling in Some Cases**

While the block-off improves cooling in most situations, it could lead to slightly lower engine bay temperatures in very cold conditions. However, this is rarely a practical issue unless you re running extreme modifications (e.g., nitrous oxide or extreme forced induction).

3. **No Direct Benefit for Stock or Mildly Modified Engines**

If your engine is stock or only lightly modified (e.g., minor tuning or mild turbo), the benefits of the block-off may be negligible. The stock ACV is already effective for most everyday driving, and the block-off may not provide noticeable improvements.

4. **Requires Additional Cooling Modifications to See Full Benefits**

If you re running a stock radiator and stock cooling fans, the block-off will help, but the gains may be modest. For the most significant improvements, pairing the block-off with an upgraded radiator, larger fans, or a performance cooling system (e.g., a front splitter or chin spoiler) will yield better results.

5. **Minimal Impact on Fuel Economy**

While the block-off reduces minor airflow resistance, the impact on fuel economy is likely to be very small unless you re running a heavily modified engine. Most drivers won t notice a significant difference.

6. **Not a Cure for Poor Cooling Systems**

If your cooling system has other issues (e.g., a failing water pump, clogged radiator, or inadequate coolant), the block-off alone won t fix them. It s a supplementary upgrade, not a standalone solution.

7. **Potential for Increased Radiator Fan Noise**

With the ACV removed, the radiator fan may run more frequently or at higher speeds to maintain cooling, which could increase fan noise in some cases. This is usually minor but worth considering if noise is a concern.

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### **Conclusion**

The **Radium 20-0449 ACV Block-Off** is a practical and cost-effective upgrade for Mazda 13B engines, particularly if you re running modifications that increase heat output (e.g., forced induction, high-compression kits, or turbocharging). It removes a potential failure point in the cooling system, improves airflow to the radiator, and simplifies the setup. For stock or mildly modified engines, the benefits are modest but still worthwhile if you re looking to optimize cooling.

However, the block-off is not a magic solution it works best when paired with other cooling upgrades (e.g., a larger radiator or upgraded fans). If your engine is already well-cooled and you re not planning further modifications, the benefits may not justify the cost.

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### **Recommendation**

- You re running a modified engine (turbocharged, forced induction, or high-performance tuning).

- You ve noticed overheating issues or suspect the stock ACV is restricting airflow.

- You re upgrading your cooling system (e.g., adding a larger radiator or fans) and want to maximize efficiency.

- You want a simple, low-cost way to improve cooling reliability.

- Your engine is stock or only lightly modified, and you re not experiencing overheating.

- You re on a tight budget and can t afford other cooling upgrades.

- You re uncomfortable with removing a component that was originally part of the system (though the block-off is a safe modification).

- You re running extreme modifications (e.g., nitrous oxide) and need additional cooling solutions beyond what the block-off provides.

For most performance-oriented Mazda 13B owners, the Radium ACV Block-Off is a **worthwhile upgrade** that enhances cooling efficiency and reliability without major drawbacks. Pair it with other cooling improvements (like a performance radiator or upgraded fans) for the best results.

Details:

Type of Return Request. The low-profile countersink stainless steel screws and anodized aluminum plate permits the necessary room for a secondary top feed fuel rail. Deleting the ACV cleans up engine by decreasing clutter and disarray. The ACV Block-Off kit replaces the air control valve and blocks port on Mazda 13B-REW lower intake manifold.

Buyer receives an item materially different from what they ordered. Buyer refuses delivery due to visible damage incurred during shipping or caused by the carrier. Buyers changes mind, buyer remorse or price difference.

part #: 200449 prices

• $45.69-$196.99

specifications fueltanksysteme:

• for makes: Mazda
• brand: Radium
• mpn: 20-0449
• part type: Block

payments fueltanksysteme:

• other
• credit card: Visa
• wallet: Paypal

shipping fueltanksysteme:

• transit: 5-10 Days
• type: Calculated
• carrier: USPS, UPS
• cost: $13.64
• class: Expedited
• service: USPS Priority Mail, UPS 2nd Day Air

returns fueltanksysteme:

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

offer fueltanksysteme:

• sold: 0
• options: Ship-to-home
• quantity: 10
• availability: In Stock
• started: February 25, 2026

seller fueltanksysteme:

• city: Walnut, California
• # reviews: 32243
• rating: 99.9%

general fueltanksysteme:

• Car Truck Parts Accessories > Air Fuel Delivery > Fuel Tanks Filler Necks
• condition: New

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