What premix oil should I use for my Mazda RX-7 FD?

For your FD RX-7, there are several proven premix options depending on your setup and fuel type. The general rule is to look for a high-quality JASO FD or TCW-3 rated 2-stroke oil.

Recommended Brands

• Idemitsu Rotary Premix: Made specifically for rotaries and highly recommended, though it can be on the expensive side ².
• Amsoil Interceptor / Amsoil 2-Cycle: Burns clean and is a popular high-quality JASO FD option ⁷.
• Redline Racing 2-Cycle: A synthetic that handles high heat well and burns clean ⁶.
• Klotz (Benol or R50): Excellent if you are running E85 or methanol, as it mixes well without separating ⁶.
• Pettit Racing Premix: Specifically formulated and marketed for rotary engines ⁶.
• Off-the-shelf options: Valvoline 2-stroke, Lucas Synthetic, or Shell Nautilus are also perfectly fine TCW-3 oils ². It is best to avoid cheaper options like Supertech, as it has been noted to smell like kerosene.

Mixing Ratios The amount of premix you need depends entirely on whether you still have your factory Oil Metering Pump (OMP) installed:

• With a functioning OMP: Add about 4 to 8 oz per full tank of gas to supplement the system ⁴.
• With the OMP deleted: Use about 1 oz per gallon of gas (approximately a 100:1 ratio) for normal street driving ⁸.
• High Boost / E85 / Track Use: Ratios typically increase to 1.5 oz up to 2.5 oz per gallon, depending on your horsepower and severity of use ⁶.

Emissions & Catalytic Converters If you are running the original stock catalytic converter, the long-term effects of premixing are uncertain, though it generally doesn't bother modern hi-flow cats. If you live in an area with emissions testing and have a functioning OMP, you will want to avoid premixing right before going in for a test ⁵.