Does a Mazda RX-7 FD with 500 rear wheel horsepower and a 13B engine make the car more enjoyable to drive?

Whether a 500 rear-wheel horsepower (rwhp) 13B makes an FD RX-7 more enjoyable depends entirely on what you want out of the driving experience. While hitting that power level is completely achievable, it drastically changes the handling dynamics and power delivery of the car.

Here is what to consider before targeting that horsepower figure:

Traction and Handling Balance The FD is highly praised for being extremely nimble, lightweight, and communicative, allowing the suspension to provide excellent feedback to the driver ⁵. However, the chassis lacks modern driver aids like traction control. Pushing 500+ rwhp in a lightweight car without these aids can make it a handful to drive ¹. Putting that much power to the ground is notoriously difficult on standard street setups; in one case, a 500+ rwhp FD struggled for traction so badly it only managed a 15-second quarter-mile and nearly hit a barrier ¹.

Powerband and Turbo Lag To achieve 500+ rwhp on a 13B, you have to run a very large turbocharger, which usually comes at the cost of low-to-mid range response. A massive turbo (like a BorgWarner S475 or GT4094R) moves the powerband far to the right. As an example, a large-turbo setup might only make around 225 rwhp at 5,000 RPM ⁷. This means you have to constantly keep the engine at very high RPMs (shifting around 7,500 RPM) just to stay in the powerband. For curvy roads or standard street driving, giving up that mid-range punch can make the car feel sluggish out of corners.

The "Sweet Spot" Alternative If you want a car that retains its nimble handling and offers responsive acceleration, aiming for around 400 whp is often considered a much more enjoyable target. This provides more usable power, less turbo lag, and significantly fewer drivetrain issues while keeping the car balanced ¹.

Making 500 RWHP Work If you are committed to 500+ rwhp, it can still be built into a reliable street car if you don't cut corners:

• Turbo Selection: Select a modern, highly efficient turbo like a BorgWarner EFR 9180. This helps move the power curve slightly left to improve low-end response without sacrificing top-end output ⁷.
• Supporting Mods: You will need top-tier engine management (like an Adaptronic ECU), ample cooling (dual 24-row oil coolers), a robust fuel system, and potentially methanol injection to keep combustion temps safe ⁷.

In short: 500 rwhp turns the FD into an incredible highway-pull or drag machine, but if you prefer spirited backroad driving where immediate throttle response and chassis balance are key, you may actually find a 350-400 rwhp setup far more enjoyable.