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The Mazda RX-7 is a beloved sports car known for its lightweight design and rotary engine. However, many enthusiasts have turned to the LS swap as a way to boost performance significantly. This guide will take you through the process of swapping an LS engine into an RX-7, increasing horsepower from 300 to 600 HP.
Understanding the LS Swap
The LS swap involves replacing the RX-7’s original rotary engine with a V8 engine from General Motors. This conversion is popular due to the LS engine’s power potential, availability, and aftermarket support.
Planning Your Build
Before diving into the swap, careful planning is essential. Consider the following:
- Budget: Determine how much you are willing to spend on the entire project.
- Engine Choice: Decide which LS engine you want to use (e.g., LS1, LS3, L92).
- Power Goals: Set realistic horsepower targets based on your engine choice and modifications.
- Parts List: Create a comprehensive list of parts needed for the swap.
Necessary Parts and Tools
Gathering the right parts and tools is crucial for a successful LS swap. Here is a list of what you will need:
- LS Engine (choose based on your power goals)
- Engine Mounts (specific to RX-7 LS swaps)
- Transmission (T56 or 4L60E recommended)
- Wiring Harness (LS swap specific)
- ECU (compatible with your LS engine)
- Fuel System Upgrade (new fuel pump and lines)
- Exhaust System (headers and custom piping)
- Cooling System (radiator and hoses)
- Driveshaft (custom length for RX-7)
- Miscellaneous tools (wrenches, sockets, etc.)
Step-by-Step LS Swap Process
Step 1: Preparation
Start by preparing your workspace. Ensure you have enough room to work on the RX-7 and access to all necessary tools. Disconnect the battery and drain fluids from the car.
Step 2: Remove the Rotary Engine
Carefully remove the rotary engine from the RX-7. This involves disconnecting the wiring harness, exhaust, and fluids. Make sure to keep track of any parts you may need later.
Step 3: Install Engine Mounts
Install the LS engine mounts onto the RX-7 chassis. Ensure they are securely fastened and positioned correctly to accommodate the new engine.
Step 4: Fit the LS Engine
Carefully lower the LS engine into the engine bay, aligning it with the newly installed mounts. Make sure it fits properly without interfering with other components.
Step 5: Connect the Transmission
Attach the transmission to the LS engine. Ensure that the transmission mount is also installed correctly and that it aligns with the RX-7 chassis.
Step 6: Wiring and ECU Setup
Install the wiring harness for the LS engine. Connect it to the ECU, which should be mounted securely in the RX-7. Ensure all connections are correct to avoid electrical issues.
Step 7: Upgrade the Fuel System
Replace the fuel pump with a higher capacity unit suitable for the LS engine. Upgrade the fuel lines to handle the increased fuel flow and pressure.
Step 8: Exhaust System Installation
Install the exhaust headers and custom piping to connect to the exhaust system. Ensure there are no leaks and that it fits well within the RX-7’s chassis.
Step 9: Cooling System Setup
Install a new radiator and connect the hoses to the LS engine. Ensure that the cooling system is efficient enough to handle the new engine’s heat output.
Step 10: Driveshaft Installation
Measure and install a custom driveshaft that fits the RX-7 and connects to the new transmission. Ensure it is balanced and secure.
Final Steps
After completing the installation, double-check all connections and fittings. Reconnect the battery and fill the fluids. Start the engine and listen for any unusual sounds.
Tuning for Performance
After the LS swap, it’s crucial to tune the engine for optimal performance. Consider the following:
- Dyno Tuning: Take your RX-7 to a professional for dyno tuning to maximize horsepower and torque.
- ECU Adjustments: Make necessary adjustments to the ECU for fuel maps and ignition timing.
- Performance Upgrades: Consider adding performance parts such as a cold air intake or upgraded camshaft for additional horsepower.
Conclusion
The LS swap in a Mazda RX-7 can dramatically increase horsepower and transform your driving experience. With careful planning and execution, you can achieve a powerful, reliable, and exciting vehicle. Enjoy your new ride!