3b Porting on the Mazda Rx-7: Before and After Dyno Results (220 to 280 Hp)

by

The Mazda RX-7 is an iconic sports car known for its lightweight design and rotary engine. One of the most popular modifications among RX-7 enthusiasts is the 3B porting process, which significantly enhances engine performance. In this article, we will explore the before and after dyno results of a Mazda RX-7 that underwent 3B porting, showcasing the increase in horsepower from 220 to 280 HP.

Understanding 3B Porting

3B porting refers to a specific modification technique applied to the intake and exhaust ports of the rotary engine. This process involves enlarging and reshaping the ports to improve airflow, which can lead to increased power and efficiency. The RX-7, particularly the third generation (FC and FD models), can greatly benefit from this modification.

Before Dyno Results

Before the 3B porting process, the Mazda RX-7 was running a stock setup. The dyno results indicated a maximum output of approximately 220 horsepower. This level of performance, while respectable, left room for improvement. The following factors contributed to the initial horsepower figures:

  • Stock intake and exhaust systems that restricted airflow.
  • Standard porting that limited engine efficiency.
  • Factory tuning that optimized for reliability over performance.

The 3B Porting Process

The 3B porting process involves meticulous work on the engine’s ports. It is crucial to ensure that the modifications are done correctly to avoid any detrimental effects on engine performance or reliability. Here are the key steps involved in the 3B porting process:

  • Disassembly of the engine to access the rotor housings.
  • Careful measurement and planning for port modifications.
  • Enlarging the intake and exhaust ports for better airflow.
  • Polishing the ports to reduce turbulence and improve flow.
  • Reassembly and thorough testing to ensure proper function.

After Dyno Results

After completing the 3B porting process, the RX-7 was re-tested on the dyno. The results were impressive, showing a significant increase in horsepower. The new dyno figures revealed a maximum output of 280 horsepower. This increase of 60 horsepower is a testament to the effectiveness of the 3B porting process. The following factors contributed to the enhanced performance:

  • Improved airflow through the enlarged ports.
  • Enhanced engine efficiency due to better tuning.
  • Increased power band, providing a more responsive throttle.

Comparative Analysis

The comparison between the before and after dyno results illustrates the substantial impact of 3B porting on the Mazda RX-7’s engine performance. Here is a summary of the key differences:

  • Before Porting: 220 HP at stock configuration.
  • After Porting: 280 HP post-3B porting.
  • Power Increase: 60 HP gain.
  • Torque Improvement: Enhanced torque delivery across the RPM range.

Conclusion

The 3B porting process on the Mazda RX-7 has proven to be a highly effective modification for those seeking to enhance their vehicle’s performance. With an increase from 220 to 280 horsepower, enthusiasts can experience a more exhilarating driving experience. However, it is essential to ensure that such modifications are carried out by experienced professionals to maintain engine reliability and performance.

Further Considerations

While the results of the 3B porting are impressive, potential modifiers should consider the following:

  • Consult with a professional to assess the best porting options for your specific RX-7 model.
  • Consider additional modifications such as upgraded exhaust systems and ECU tuning for optimal performance.
  • Regular maintenance is crucial to ensure the longevity of a modified rotary engine.