By Turbo Magazine Staff
Photography by Turbo Magazine Staff
By just the numbers, there is a great deal of potential being realized in this 1993 Mazda RX-7. One of the most prolific street machines we have seen, this FD belts out 645 hp at the wheels, runs 10.01 on street-spec tires and 9.62 on slicks--impressive numbers indeed.
The rx7.com Mazda has gained unprecedented bragging rights in the tightly knit world of rotary performance--and this stature has come quite quickly. While Adam Saruwatari is the most well-known name in RX-7 circles, Ari Yallon, Chris Ott and Rotary Performance have taken FD performance where Adam and A&L Racing couldn't. Adam's RX-7 ran 10.12, 10.15 and 10.17 on slicks in stock driveline configuration. The crew swapped to a G-Force gearbox and went 9.63 at first asking. The aftermarket transmission put Adam in the Outlaw Class, but the beauty of the deal was a quick swap back to a Mazda gearbox and he was cleared for takeoff in the Quick Class.
Ari and Rotary Performance took their FD to 10.01 on street tires, then merely swapped to slicks and blasted a 9.62--all via the stock Mazda driveline.
The rx7.com Mazda is street registered and capable of prowlin' the streets at will (as it did for our photo shoot) but with the shop's reputation riding along with the car, you'd think the red rocket sees the strip more than the street. This is not altogether true.
"This car has always kept to the philosophy of remaining streetable. Even today we test drive, tune, joy ride and even occasionally race the car on the street. It has always been street registered, inspected and runs quite smoothly in around-town situations," said Yallon. "No one ever expects the performance contained beneath its red body. Having the original suspension and clean, not overly flashy, appearance, the Mazda takes people by surprise. Being in Texas, weekend racing attracts a lot of 'rednecks' who laugh at and heckle the RX-7 as it 'tries' to race their V8s and pumped-up pickup trucks. They don't laugh for long, usually about half a pass. We've also frequently crashed the parties of exotic car owners [and end up] beating Vipers, 'Vettes and even Ferraris."
Rotary Performance prepped the 13B rotary engine for high-power output. The RP crew custom street ported the rotors to its own secret specs. Porting a rotor housing is the equivalent of porting the head on a piston engine, and increasing the airflow into the engine increases the power potential of the motor. A set of special Rotary Performance 3-mm apex seals were added to keep the engine together under high-boost operation. The 13B runs a stock intake manifold that is fed by an upgraded rx7.com throttle body. A GReddy Power Extreme system is in charge of expediting the flow of exhaust gases while a 94-mm tip provides a nice finishing touch. Beyond the mods, the Rotary Performance crew credits immaculate engine assembly as another major factory in the FD's durability and consistency at the strip and its civilized nature on the street.
Give Me A Boost
The Mazda's original sequential twin-turbo configuration has been altered to single-turbo status. The rotary engine is dutifully pressurized by a GReddy turbo upgrade package featuring the company's race-proven T78 turbocharger. Rotary Performance has set max boost to 28 psi and called on a big air-to-air GReddy intercooler to cool the charge air as it heads to the engine. A GReddy PRofec B is in charge of regulating boost in conjunction with a Type R wastegate.
Rotary Performance attacked fuel enrichment with a set of upgraded 550cc main injectors and a 1600cc secondary injector. RP custom fabricated the fuel rail and added one of its high-flow, in-tank fuel pumps.
On the ignition side, the Mazda runs a Jacobs Rotary Pro Pak, Jacobs race-spec coils, Jacobs plug wires and NGK racing plugs to keep the Wankel running efficiently at full song. The Pro Pak is a key component because the firing cycle of a rotary is much more complex than that of a piston engine.
For extra thrust, a Nitrous Express wet-manifold system has been plumbed into the works. The laughing gas has been jetted to a conservative 75 hp and, while its 36-percent oxygen content by weight adds power, the cooling effect of nitrous also comes in handy, especially in the harsh summer heat that hits the Lone Star State.
The system is used as a spool-up assist that creates extra "cylinder" pressure. This leads to more exhaust gases, which, in turn, speeds the spool-up of the turbo. While this usage is nothing new, it should be noted that Chris has the nitrous programmed to stay on until a whopping 22 psi (most systems turn off at 5 to 7 psi). There is a steering wheel-mounted override that, when activated, pumps out the funny fog for the entire run.
Please Stay Tuned
Rotary Performance handled all the tuning and utilized its Dynojet chassis dyno to chart the progress. Many of the actual tuning runs were performed on the street. The Wankel is controlled by a Haltech E6K engine management computer. The E6K system is very similar to the E6S series used on many of the quickest Diamond Stars, but it offers double the microprocessor speed, an internal barometric pressure sensor, additional PWM outputs and updated software.
The E6K has datalogging capability that allows the user to see data in real time to better facilitate accurate tuning adjustments. As far as the act of programming is concerned, the Haltech system allows the manipulation of graphs in lieu of inputting numbers to control fuel delivery or tweak ignition curve maps. Operating parameters can be tuned in 500-rpm increments up to 10,500 rpm. With the Haltech system on the job, Chris has extracted some impressive power numbers from the 13B. On the Rotary Performance Dynojet, the RX-7 spun the rollers to the tune of 561 hp and 421 lbs-ft of torque off the bottle. With the Nitrous Express system activated, the 13B generated 645 pavement-pounding horsepower and 470 lbs-ft of torque. That'll get you down the highway and then some.
Hook 'n' Cook
The RX-7 is a leading-edge performance machine right out of the box. In fact, early R1 "race-spec" models were sprung so stiffly that even racers complained. With such a good foundation, RP only had to add a few well-placed tweaks to get big-time 60-foot performance. Tokico five-way adjustable shocks (Front Right and Front Left) and Suspension Specialties springs give the Mazda the correct stance while a Kaaz limited-slip differential and special rx7.com axles ensure precise and durable power transfer. Gear selection is attained via an rx7.com shifter and Bonez clutch. The shock and spring combo are certainly doing their job as the Mazda nails 1.54-second 60-foots on street tires and 1.37-second 60-foots on slicks.
The car has been sprayed Vintage Red by Krause Paint & Body, fitted with 1999 RX-7 taillights (from a Japan-spec model) and adorned with vinyl graphics. The use of graphics allows Ari to look the part. At the strip they can get 9-seconds worth of PR with the stickers. Peeling the vinyl transforms the car to a sleeper, so Ari can take down the pretenders on the street.
While in full-cruise mode, the Mazda runs Yokohama AVS Sport rubber and SSR Integral five-spoke aluminum. At the strip in street class trim, the RX-7 flexes Mickey Thompson ET Streets wrapped around Weld Racing Aluma Stars. Mickey Thompson ET Drag slicks are bolted on when 9-second e.t.s are needed. For safety, a chrome-moly roll cage, NHRA-approved to 7.50-seconds, is on call. The RP crew fabricated a control panel that commands the Nitrous Express system. The panel is housed in the center console and can be easily concealed, keeping the street stealth illusion alive. For weight balance, the battery has been moved inside the car; to keep its street heritage intact, the stock stereo system has been retained.
The Mazda can bump it in many ways. The car is a silent assassin. Since it runs a complete exhaust system the stereo can be played around town. At the strip, the Mazda can bump it by bumping off the competition--10.01 on street tires is a tough nut to crack. Swapping to slicks and running 9.6 puts the RX-7 near the top of the food chain in the Quick Class. Since the RX-7 is a street car, it makes most of its strip passes under the street class banner. Going by the numbers--and they are impressive--the rx7.com Mazda has taken stock-spec rotary performance to never-before-seen heights.
[Mail me] [To Lightning home] [To my home page] [Copyright Notice]