1995 Mazda RX-7 FD

At first glance, there's little indication Gordon Monsen's 1995 RX-7 is anything more than just a slightly lowered, subtly altered example of a fine breed. There's nothing to suggest the car's claimed 455-hp engine or racecar-like handling. It keeps its ferocity to itself, like a well-trained Rottweiler that only growls when provoked. Provoke it, however, and you're in for a nasty bite.

Monsen started sharpening his RX-7's fangs immediately after he bought the car. "I wanted to build a car that was as normal and smooth feeling as though a factory built it," he says. By changing one part of the system, the rest of the vehicle had to be changed to compensate. Thus, much of the work on his car is not just designed to make it faster or handle better, but to achieve those goals without ruining reliability or concentrating too much on one aspect of performance while neglecting others. Monsen tapped widely respected Mazda specialist KD Rotary in Nazareth, Pa. to do the wrenching and tuning work.

Through his previous tuning experience, he knew a stand-alone computer was the best way to control the functions of the car the way he wanted to. He decided on an Australian-made Haltech engine management system. It gives him the programmability he wanted, at a reasonable price. Gone were the separate boost controller, additional ignition controller and other piggyback computers previously used.

The Haltech has its work cut out for it. The boost, fuel and ignition systems are all significantly upgraded and under the computer's control. On top of this, the rotary engine itself was street ported by KD Rotary and features such custom components as a mechanical oiling system. The air and power steering pumps have been removed to reduce parasitic losses, while the pulleys for the alternator and air conditioning compressor are custom aluminum pieces. The ABS controller is gone, as is the cruise control mechanism. Don't go looking for the EGR either, it's in the circular file too.

Under the hood lies a single giant Mitsubishi T78 turbo. Normally, a turbo this size would result in unacceptable lag, but Monsen modified his with a lightweight and larger Garret TV-series compressor wheel. Boost is controlled through the Haltech computer, with a Tial 46mm wastegate bleeding off excess boost. Maximum boost is 18 psi at 6000 rpm, but as the revs climb, it's slowly dialed back to 15 psi at the 8000 rpm redline in the interest of reliability on pump gas. After being sucked through a custom airbox with a K&N filter, the compressed air is pumped through custom intake piping to a big Mitch Piper intercooler. A GReddy Super Sequential blow-off valve prevents compressor surge. At the rear wheels, Monsen tested his car at 455 hp, a very respectable figure.

Adding gasoline to the compressed air is the job of a seriously beefed up fuel system. With the exception of the fuel tank, very few stock components are left. The in-tank fuel pump is a Bosch unit capable of pumping 30-gph and delivering 70-psi at redline. A Bell rising rate fuel pressure regulator makes sure pressure doesn't fall off during high boost. Delivering fuel to the engine is the job of AN -6 stainless steel lines and Earl's AN fittings. A Rotary Performance aluminum fuel rail is filled with two Bosch 550cc primary injectors and two more Bosch 1600cc secondary injectors.