High school is a time when life begins to take shape. Personality traits and obsessions become clearer. For better or worse those years can brand a person for life. Any auto enthusiast can tell you that around this time one particular brand or make of vehicle can become part of their DNA. For Chuck Duncan of North Little Rock, Ark., he found his true love his senior year-1992-in a Mazda dealership and hasn't looked back. After an all-too-brief introduction, he would spend the next eight years pining for her before she finally became his.
Back in '92, Chuck's obsession took hold of him with his first RX-7, an '85 model. The subsequent eight years and five first-gen RX-7s later his Mazda affliction was deep and incurable. Then in 2000, he came across a brilliant black 1993 Mazda RX-7 R1, just like the one he sat in back in '92. The lure of obtaining his high-school love with a deal that included a partial trade of his then current '85 RX-7 GSL-SE and cash was too tempting to pass up. The deal was struck at Six Flags Over Texas, in Arlington, Texas, over 350 miles away. The six-hour ride home must have felt like the greatest roller-coaster ride of his life, filled with excitement and touch of fear while excessive amounts of adrenaline coursed through his system.
The car was slightly modified at the time, which was OK for a while. But Chuck wanted more from their relationship, more power and more style. As it is for most of us, car modifications came when time and money allowed. Some parts have stayed but most have been upgraded or replaced as the car's buildup progressed.
The rotary engine has gone through changes since day one in search of more power. For this latest incarnation, Demented Racing was called in to assemble the engine. To start with, the twin-turbo setup was ditched in favor of a single Garrett GT35/40 turbo. For increased flow the manifold was ported, polished and internally hot-coated. While the rotor housings were out at Atkins Rotary getting a street port, they added some of their own 3mm apex seals. A TiAL 46mm wastegate and BOV keep boost pressures in check. Pressurized air passes through an A'PEXi GT intercooler before entering the GReddy intake elbow. Exhaust gasses are expelled through a modified A'PEXi Dual N1 cat back system to include dual 2.5-inch Borla XS mufflers.
Designing and fabbing up the fuel system fell to Polk Performance of Bryant, Ark. What they came up with to keep this twin-rotor properly fueled was to use Keith's Rails primary and secondary fuel rails, 756cc primary and 1680cc secondary injectors. Pushing the fuel to the injectors is a Walbro 255lph pump. Fuel pressure is regulated by an Aeromotive FPR. Firing off the mixture falls to Bosch HEC-715 coil packs, Magnacore R-100 10mm race plug wires and NGK Racing 10.5 heat range plugs.
Keeping the electrons flowing and the rotary engine in one piece is a MicroTech LTX12 with integrated LSM11 wideband O2 sensor. After many dyno tuning sessions this twin-rotor, single turbo RX-7 R1 puts out 460 horsepower and 337.9 lb-ft of torque at 17 psi on C-16 race gas.