Robert Choo
Photography by Gary Castillo
Courtesy of 
When conjuring up images of tube-framed import racers, one particular country dominates
the cerebral cortex--Puerto Rico. With a total population of just under 4 million, the
country unofficially produces more tube-framed racers per capita than any other country
in the world. Racing to Puerto Ricans is as much a necessity as water. When you consider
the two tracks on the island are open four days a week, racing has become a lifestyle.
Anibal Rivera of Nibo Racing exemplifies this lifestyle with his impressive tube-frame
1994 Mazda RX-7.
Rivera's RX-7 started with nothing more than a bunch of chrome-moly tubing until legendary chassis builder Kike Sheilds (pronounced "Kee Kay") fired up his welder. Kike Sheilds is the Michael Jordan of chassis builders in Puerto Rico. The Nibo Racing chassis utilizes a four-link Ford 9-inch rear-end with Afco double adjustable shocks and springs at the four corners. Just in case the parachute doesn't blossom properly at 170 mph, Aerospace calipers up front and Strange units out back are sure to bring the car to a complete halt in ample time. Aerolite aluminum wrapped with Goodyear rubbers reside under the wheelwells.
Propelling the vehicle into the 7-second club is a turbocharged rotary powerplant.
Puerto Ricans love the rotary engine, to say the least. You can find a rotary in almost
every possible racer; be it a Datsun, Nissan, Toyota, Mitsubishi or even a Honda, don't
be surprised to find a rotary engine in it. Rafael Padilla massaged the 13B powerplant to
handle the abuse of force-feeding. He fortified the engine with stronger apex seals from
Francesco Iannetti, known as the Giorgio Armani of apex seals. Considering the plan called
for injesting 30-plus psi of boost pressure, it better have the best of the best. Padilla
also ported the rotary housings to increase airflow before balancing and blueprinting the
entire powerplant. Sheilds was also responsible for building the turbo manifold. Although
the turbo specifications were kept secret (for obvious reasons), from the pictures, we can
tell that the hairdryer is a T4 unit. The T4 turbo has been tuned to an astronomical 38
psi of boost pressure, but at the car's coming out party, it was only running 33 psi. On
the intake side the rotary runs a Sakura Motorsports throttle body with a Jaytech intake
manifold.
Get this, a total of eight 1,600cc Kinsler squirters are required to meet the Wankel's
insatiable appetite for alcohol. Twin Weldon fuel pumps supply the alcohol to a pair of
Kike Chassis Shop fuel rails. The fuel system is regulated by a single Kinsler regulator.
Igniting the compressed fuel are dual MSD 7AL-2 boxes with two MSD Pro coils. The amped
charge is sent through Moroso plug wires, zapping NGK spark plugs. Engine management chores
are handled by a top-of-the-line Haltech F9-8 fuel computer. The owner claims that this
potent combination is capable of producing 700 hp at 38 psi of boost pressure.
The rotary engine's kinetic energy is transferred to a McLeod flywheel and clutch. A G-Force air shifted five-speed transmission delivers the power to a Mark Williams driveshaft and Mark Williams axles. Extra-wide Goodyear 31-inch gumballs launch the RX-7 to blistering 1.16-second 60-foots and 7.92-second quarters.
The RX-7 has already surpassed Rivera's expectations as the Mazda was built originally
with low 8-second runs as the target. Amazingly enough, the Mazda blistered a best of
7.92-seconds at its very first outing. With only four passes under its belt, the "7" is
sure to go quicker with more runs. Rivera also plans to turn up the boost after he
finishes dialing in the chassis, so watch out. The Nibo Racing "7" is out to give some
contenders a beating at the next event. Who knows? Maybe Rivera might become the next
world's fastest door slammer. One thing is certain, back home in Puerto Rico, he will be
busy four days a week.
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