Supporting Transmission Upgrades for 700+ Hp Rx-7 Ls Swaps

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The RX-7 is a beloved sports car that has captured the hearts of many enthusiasts. With its lightweight chassis and agile handling, it provides an excellent platform for performance upgrades. One of the most popular modifications is the LS engine swap, which can easily push the power output beyond 700 horsepower. However, to handle this significant increase in power, suitable transmission upgrades are essential.

Understanding the Need for Transmission Upgrades

When swapping an LS engine into an RX-7, the stock transmission is often not capable of handling the increased torque and horsepower. Upgrading the transmission is crucial for several reasons:

  • Power Handling: Stock transmissions can fail under high power loads.
  • Reliability: Upgraded transmissions are designed to endure extreme conditions.
  • Performance: Enhanced gear ratios can improve acceleration and top speed.

There are several transmission options available that can effectively handle 700+ horsepower in an RX-7. Each option has its pros and cons, depending on the intended use of the vehicle.

  • TH400: A three-speed automatic known for its strength and durability.
  • 4L60E: A four-speed automatic that provides a good balance of performance and drivability.
  • 6L80E: A six-speed automatic that offers improved fuel efficiency and performance.
  • T56: A six-speed manual transmission favored for its performance and engagement.

TH400 Transmission Overview

The TH400 is a popular choice for high-horsepower builds due to its robustness. This transmission can handle significant torque and is relatively easy to find parts for.

  • Pros: Extremely durable, simple design, and easy to modify.
  • Cons: Limited gear ratios compared to modern options.

4L60E Transmission Overview

The 4L60E is a popular four-speed automatic that offers a good compromise between performance and comfort. It features electronic controls, making it more efficient than older transmissions.

  • Pros: Better fuel economy, smoother shifts, and more gear options.
  • Cons: Requires a reliable tuning solution for optimal performance.

6L80E Transmission Overview

The 6L80E is a six-speed automatic that provides advanced technology and improved performance. It is ideal for those looking for a balance between track performance and daily drivability.

  • Pros: Excellent performance, adaptive transmission control, and more gear ratios.
  • Cons: Higher complexity and cost compared to simpler options.

T56 Transmission Overview

The T56 is a six-speed manual transmission that is favored by many performance enthusiasts. Its design allows for quick shifts and a direct connection to the engine, enhancing the driving experience.

  • Pros: Engaging driving experience, robust construction, and multiple gear options.
  • Cons: Requires more skill to drive effectively and can be less convenient in traffic.

Choosing the Right Transmission for Your Build

Selecting the right transmission for your RX-7 LS swap depends on a variety of factors, including your power goals, driving style, and budget. Here are some considerations to help guide your decision:

  • Driving Style: Consider whether you prefer automatic or manual shifting.
  • Power Goals: Ensure the transmission can handle your target horsepower.
  • Budget: Factor in the cost of the transmission and any additional modifications needed.

Supporting Modifications for Transmission Upgrades

When upgrading your transmission, additional modifications may be necessary to ensure compatibility and performance. Here are some common supporting upgrades:

  • Driveshaft: A stronger driveshaft is essential to handle increased power.
  • Transmission Mount: An upgraded mount may be required for proper alignment.
  • Cooling System: An auxiliary transmission cooler can prevent overheating.

Conclusion

Upgrading the transmission in your RX-7 LS swap is a critical step in achieving reliable performance with 700+ horsepower. By choosing the right transmission and making the necessary supporting modifications, you can ensure that your vehicle performs at its best, whether on the track or the street.