1993 Wide-body Mazda RX-7 - Riding on Rails
When you think of high-performance import icons, there are definitely a few that come to mind. The Skyline, Supra, 300ZX, and RX-7. When Jack Mardikian, a veteran of the track thought about a fun weekend car to build in 1998, his first instinct was the Mazda RX-7. The 1993-1995 FD3S RX-7 was destined to be a top choice of import car tuners because of its lightweight chassis, incredible power potential, terrific balance and world class handling.
The initial builds were primarily for weekend fun. As the fun became more and more serious, Jack started investing more time and money into the car. A series of gains were soon followed by setbacks. Frustrating trial and error sessions pushed this build into high gear. Pulling out all the stops, Jack opted for a complete buildup. The transformation of this weekend car turned full race car began in 2003 when he entrusted his FD to Louis Escamilla of Rotary, Reliability and Racing (RRR) in Santa Ana, California.
Wild Wankel
The buildup of the 13B started with a "street port" performed by RRR's owner Nick Vannugteren. Since rotary engines have no valves or camshafts, porting of the housings is the equivalent of installing high-performance camshafts and porting the cylinder head. Once the "street port" was complete on the housings, a set of specially machined 9.0:1 compression ratio rotors were installed. With the basic engine assembly together, attention turned to the turbo system.
The XS Engineering turbo system is composed of a cast manifold and an XS Engineering T04X2 turbocharger. The TO4X2 turbo features a 1.0 A/R divided inlet T4 flange for good boost response. On the compressor side a T04S-family compressor section is utilized to provide high efficiency flow. While this same-spec T04X2 can happily produce enough flow for over 650 horsepower on a drag-race application, the boost and flow is limited to produce 440 wheel horsepower on this 13B. That horsepower level provides great performance with great reliability on the 13B engine that's pushed to the limit for miles at a time. An HKS 50mm racing wastegate regulates boost pressure to 15psi while spent gasses are routed through an RRR custom stainless steel exhaust.
The compressed intake charge travels through custom piping to a PWR prototype intercooler. The chilled air then flows to an RRR ported intake manifold that is port matched to the block. An Apexi blow-off valve relieves boost pressure between shifts. Supplying the 104-octane VP Racing fuel for the fire are a set of 850cc/min primary injectors and a set of 1300cc/min secondary injectors. A Nissan Skyline R33 fuel pump keeps the hungry injectors well fed all the way to redline. Lighting the air/fuel mixture is a set of HKS Super Fire Racing Iridium spark plugs powered by an XS Engineering Powerpack ignition amplifier. An Apexi Power FC stand-alone fuel computer, tuned by Koji Arai of XS Engineering, orchestrates fuel and ignition events.
Red Hot
Making 440 horsepower to the wheels with 1.3 liters generates quite a bit of heat. Competing at time attack events and numerous sanctioned track events also gets things heated up in a hurry. To combat the excess heat that the rotary engine can produce, PWR constructed a custom radiator for this FD. An RRR dual oil cooler kit was also installed to supplement cooling efforts.
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