Gordon Monsen's 1995 Mazda RX-7

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.

Once all the air and fuel is stuffed into the rotary's oblong combustion chamber, it's lit by a custom ignition system. Most rotaries use Crane or Jacobs electronics, but Monsen decided to go with MSD, based on his own personal experiences. Designing an MSD ignition system to work with the rotary and the Haltech was a challenge, however. After several calls to MSD and Haltech in Australia (not to mention some Australian tuners who had tackled this problem before), Monsen finally settled on a combination.

An MSD Digital 6 Plus controls the leading plugs, while the trailing plugs use a DIS-2. The Digital 6's exact firing and EMI suppression were important considerations given the high-rpm precision needed in this engine. The DIS-2 is essentially two MSD 6A's in one chassis, and lack the digital precision of the unit for the leading plugs. However, like the Digital 6 Plus, it fires multiple sparks below 3000 rpm, and has more output than the digital unit. Four MSD 45 KVA coils fire the plugs themselves. The whole ignition system is mounted between the passenger and cargo compartment. The lead and return wires are not only thick No. 1 gauge wiring but leading down opposite sides of the car to reduce any interference.

Monsen's attention to detail stops just short of obsessive, and crosses the line in some cases. Coolant, oil and fuel lines have all been replaced with stainless-steel braided hoses fitted with Earl's anodized fittings. For some things-such as the wastegate-custom aluminum hard pipes and banjo connectors are used. All underhood wiring has been Thermo-Tec sleeved. All the vacuum hoses have been replaced by Russell stainless steel covered Teflon hoses. The list goes on and on, and while some psychiatrists might consider this kind of obsession with details unhealthy, it resulted in tons of reliable horsepower from a car with a less than stellar record.

Gone is the dip in power caused by the transition from a small turbo to a large one. The bigger turbo lags a bit more, but the payoff is incredible power all the way to redline. Even at 4500 rpm in third gear, the rear end will break loose. "Hell, the car should come with a manual on driving sideways," says Monsen.

Adam Saruwatari could write a novel on the stoutness of the RX-7's stock driveline, so it's not surprising few changes were made here. The transmission is stock, but uses a 4.37:1 final drive ratio. A Centerforce clutch and lightweight 8.5-lb flywheel rounds out the driveline modifications.

It would've been easy to stop there, maybe throw some lowering springs on the car, and call it a day. But this wasn't even an alternative for Monsen. When the time came for chassis improvements, the same attention to detail found under the hood was applied.

Originally, better springs and shocks were installed, but Monsen wanted to do more than just keep up with newer Porsches and Ferraris at the track. He wanted to beat them, and this means specialized hardware. He was referred to Tri Point engineering in Canoga Park, Calif. because of the company's experience with Koni's 2812 racing suspension. He was cautious about putting this fully adjustable race-designed suspension on his car, but Tri Point assured him the ride wouldn't be compromised-and might even be better-so the parts went on.

The cost of equipment is a deterrent to most street tuners-almost $5,000 for the parts themselves. But the change was remarkable. "They made more of a difference in the overall character of the car than any other change I had made," Monsen says. "It's as though there are four boxers dancing at each corner; light on their feet, yet strong and adjusting to every jab of the road."

Other suspension improvements include M2 Performance toe and trailing links and bushings. Cusco front and rear strut tower braces aid in chassis rigidity. Combined, they allow the Konis to do their work without compensating for chassis flex or squishy bushings.

Blistering acceleration and high-g turning capability is useless without the right set of brakes. After using Wilwood brakes for a number of years, the car's enhanced performance demanded better stopping power. AP brakes from M2 Performance were the answer. The big, lightweight 13-inch Champ Car front rotors are pinched by four-piston AP calipers and feature machined mounts and aluminum hats. Steel brake lines are filled with Motul brake fluid. Not only does the car stop better than just about anything on the street, the lightness of the components keeps unsprung weight down, aiding handling.

Like the muscles rippling under the taut skin of a Doberman, there are only the subtlest of visual clues to the RX-7's awesome performance. The lowered body hunkers over 17-inch Manaray wheels. The tires wrapped around those wheels are serious-looking Bridgestone Potenza S02 Pole Position tires. A fat A'pexi stainless- steel exhaust pipe pokes from under the rear bodywork. Adorning the doors are chrome mirrors only the most astute will recognize as being from BMW's supercar, the Z8.

The interior of Monsen's car is as no-nonsense as the exterior. All the gauges have been replaced with Autometer Ultralites. Knig SK5000 seats hold Monsen in place during hard cornering. A Momo competition wheel, Voodoo aluminum shift knob and emergency brake handle, and CWC aluminum pedal assembly are present for the sake of performance and style, while Wilton wool carpeting and Dynamat sound deadening are in the name of comfort.

With a car so highly tuned, you could say street driving would be unrealistic at best. However, Monsen still drives his RX-7 at least three or four times a week. And as you might expect, it gets plenty of track time. Although it's not set up as a drag car, it manages mid-to-low 11-second times at the strip. More often than not, it's found at road courses such as Virginia International Raceway, embarrassing the Porsche and Ferrari drivers who were foolish enough to ignore this RX-7's growl.

RD Rotary RX-7