Is Freeze-12 a good refrigerant for the Mazda RX-7 FD air conditioning system?

Depending on the year and region of your FD RX-7, the factory A/C system was originally designed for either R12 or R134a:

• US-Spec Models: The transition from R12 to R134a occurred around the 1994/1995 model years. Vehicles built in early 1994 or earlier came with R12, which features screw-on type fittings. Models from 1995 onward came factory-equipped with R134a, which utilizes quick-disconnect fittings ¹.
• JDM Models: The switch to R134a happened a bit earlier, beginning on July 20, 1993, coinciding with the start of the Version 2 cars ¹.

If your vehicle currently has an R12 system and you need to recharge or repair it, converting to R134a is the standard path. Doing a straight R134a conversion using the original FD components can result in subpar cooling at idle. To fix this, you can use a modern R134a conversion package—such as the kit from JP3 Motorsports—which upgrades the system using an RX-8 compressor and condenser for much better performance ².