Relatively Straightforward (Still Challenging):
* Nissan VG-series (from other Z31s or related Nissans): This is the easiest path. Swapping in a higher-spec VG30ET (turbo) from a later Z31 or a VG30DE (naturally aspirated) is relatively straightforward, requiring less fabrication. You'll still need to address wiring, ECU, and potentially transmission compatibility. Finding a suitable donor car is often the biggest hurdle.
* Nissan RB26DETT (Godzilla Engine): A popular but significantly more challenging swap. This iconic engine from the Skyline GT-R requires extensive fabrication and custom work, including engine mounts, exhaust, and cooling systems. Expertise in fabrication and wiring is crucial.
More Advanced Swaps (Extensive Fabrication Required):
* LS-series (Chevrolet): Very popular due to readily available power and aftermarket support. This swap requires significant custom work, including engine mounts, wiring harness adaptation, and potentially transmission adaptation. The LS series is relatively compact and lightweight.
* SR20DET (Nissan): Another popular choice from the Nissan S-chassis (e.g., 200SX, Silvia). It's smaller and lighter than the VG series and offers good power potential, but it still requires significant fabrication and custom work.
* Toyota 2JZ-GTE: A powerful and reliable engine from various Toyota models (Supra). This is a complex swap similar in difficulty to the RB26DETT, requiring significant fabrication and custom parts.
Things to Consider for ANY Swap:
* Wiring Harness and ECU: This is often the most complex aspect of any engine swap. You may need to employ a standalone engine management system (EMS) or extensively modify the existing wiring.
* Transmission: The transmission compatibility between the donor and recipient car needs to be carefully considered. You might need an adapter plate or a complete transmission swap.
* Engine Mounts: Custom engine mounts are almost always necessary.
* Driveshafts: You might need custom driveshafts to accommodate the new engine and transmission.
* Cooling System: The cooling system may need upgrading to handle the new engine's heat output.
* Exhaust System: A custom exhaust system will be required.
* Fuel System: The fuel system may need modification to suit the new engine's requirements.
Before starting any swap:
* Research thoroughly: Find detailed guides and forums specific to your chosen swap.
* Budget realistically: Engine swaps are expensive projects. Factor in all costs (parts, labor, tools).
* Assess your skills: If you lack the necessary mechanical skills, consider hiring a professional.
Choosing the "best" swap depends entirely on your goals, budget, and mechanical abilities. Starting with a VG swap from another Z31 is generally recommended for beginners, while the other options require significant expertise and commitment.
