The success of this car can be traced back through 10 years of evolution paired with a wave of new-age technology. Starting with a fresh Series 6 RX-7 engine, Pac Performance machined the rotors to accept 3mm, two-piece apex seals. The side plates have been massaged with a turbo porting to Pac's own racing specs. Reliability has been enhanced with modifications to the eccentric shaft and the use of multi-window race bearings in the rotors, as well as a complete dry-sump oiling system. Pac retained the factory intake manifold but port matched it for optimal flow. The 13B is pressurized by a Turbonetics turbo whose specs are so secret the unit was covered for the FF&R photo shoot. Pac reports max boost is regulated to 24 psi via a Garrett race-spec wastegate. The turbo sends boost through a massive RBR front-mount, air-to-air intercooler that's so big it makes one ask, "Is that an RX-2 attached to that intercooler?" The cooler extends from the base of the hood to well below the front spoiler.
Although the turbocharger...
Although the turbocharger is quite big, turbo lag is greatly reduced by the direct intercooler and turbo system plumbing. There is very little distance between the turbo and the cooler and the cooler and the intake.
Spent gases are evacuated by a custom 3.5-inch mandrel-bent exhaust system that is quiet enough to meet Eastern Creek Raceway's noise standards (a sound familiar e.g. Pomona Street Legal Drags). One of the impressive aspects of this Aussie rocket is that it has run methanol for the last couple of years and recently switched back to a special mix of VP race gas yet the car has continued to improve its performance.
As with many high-tech racers, leading-edge engine management is at the core of the matter. Pac Performance relies on a MicroTech MTX-8 system which features sequential injector control and sequential ignition timing. Ignition chores are handled by a MicroTech CDI ignition set-up that utilizes Jacobs igniters to fire heavy-duty racing coils that electrify the combustion chambers to the tune of 650 hp.
Transferring that power to the ground is a battle-proven Jerico four-speed gearbox that uses a pound billet flywheel and Tilton triple-plate clutch to engage the driveline. The Jerico was selected because it is relatively inexpensive, can be fitted with scores of different gear ratios and sports a low parasitic drag quotient. From the tranny, thrust is funneled through a Mark Williams rear end that flexes 35-spline axles and a 4-inch tailshaft. The Williams unit is stuffed with 5.88 gears which work in conjunction with 31x18.5-inch Mickey Thompson gumballs to motivate the 2420-lb Mazda at a frenzied pace. This combination nets consistent 1.28-second 60-foot times but the crew feels that 1.20s are attainable. The Mazda is described as a quarter-chassis car with a four-link rear suspension locating the Williams rear end.
A massive RBR air-sto-air...
A massive RBR air-sto-air intercooler dominates the nose of the Mazda. The 13B is commanded by a MicroTech engine management system that features sequential injector and ignition timing control and its own CDI ignition system.
Let's see it's a Mazda running a Mazda powerplant but is using a Jerico gearbox and relying on a quarter-chassis set-up. That makes it practically impossible to classify in U.S. terms (Street, Quick, Outlaw, Pro). Street Class? Yes, this mad Mazda still prowls the streets on occasion. Looking closely at the accompanying photos, you can see the car is registered for street duty (EZY 08S plate) but with 8.86-second potential the streets of Sydney are as lonely as the Outback with few takers when it comes to stoplight grand prix showdowns. Pac Performance says there is still more in the motor and Rocky and George plan to continue to push the envelope with the current set-up. If Pac Performance's rivals catch up, there are plans to infuse the RX-2 with a mist of nitrous oxide. That'll really put the squeeze on the competition.