How much horsepower can I expect from a street port on a Mazda RX-7 FD?

The exact horsepower you can expect from a street port on your FD RX-7 depends heavily on how aggressive the port is, your turbo setup, and your supporting modifications.

As a general baseline, a street port typically provides a 10% to 20% gain in horsepower over a standard port configuration, and it is most effective when paired with higher-flowing exhaust components ⁶. This translates to roughly a 10% increase in horsepower at the wheels, or a gain of around 30 horsepower, depending on the exact size and shape of the port ¹.

If you are upgrading the turbocharger, those gains will scale significantly. For example, an FD with an aggressive street port, a Precision 6265 turbo running at 15 psi, a standalone ECU, and water-methanol injection can expect to make around 420 to 450 horsepower at the crank ². Pushing beyond that power level usually requires increasing the boost pressure or stepping up to a bridgeport.

To give you a more accurate estimate for your specific build, what turbo setup, boost level, and engine management system are you currently running or planning to use?