In just over a year, the little car company that could quietly sold more than 100,000 RX-8s. In the same period, GM sold 60,000 of the much ballyhooed, phallus-in-a-box H2.
Just as quietly, SR Motorsports in Brentwood, Calif., produced a cadre of upgrades to the growing army of Renesis-armed enthusiasts.
The Renesis fed the rotary naysayers crow, proving the viability of the Wankel engine despite CARB's best efforts to install us all into rubber band-propelled vehicles. Asked to list a downside to a fabulous chassis and overall driving experience, however, owners usually point to an engine that doesn't muster as much might as it might.
Ray Lockhead, owner of SR Motorsports, is known for forcing enough air through ported ports to zing the millennium horsepower mark, and for attaching them to second- and third-generation RX-7 chassis running eights in the quarter mile. He is currently finishing up a 1400-hp, three-rotor, tube-frame RX-8 for the NHRA's Pro Modified Class.
The rebirth of the rotary in 2003, unsurprisingly, found Ray standing in line at the Mazda dealer. His red RX-8 became an immediate breeding ground for the parts his shop produces and sells. SR's answer to demands for more juice is a number of powertrain bolt-ons, available individually or as a package. The result of more than 900 dyno pulls on this very car is SR's full GT-4 package that produces a claimed 210-wheel hp, or 37 more than stock, on the shop's Dynojet.
SR's cold-air ram intake system places the filter in a sealed chamber that draws fresh air from behind the front bumper and is manufactured from T-6061 billet aluminum and polished 304 stainless steel. SR uses 3.5-inch-diameter intake piping-which is huge, but not much larger than stock-that hints at the lungs built into this engine and bodes well for future horsepower extraction.
With the ingress of combustibles massaged, SR installed its own 304 stainless high-flow catalytic converter attached to a 63mm-thick wall 304 stainless exhaust system. V-band clamps are used at critical junctions to ensure a leak-free exhaust system.
Traditional nuts and bolts can loosen over time. It's a serious issue, given the significant thermal expansion common in rotary engine exhaust systems. With exhaust gas temperatures that make piston engines look like a hair dryer by comparison, managing a rotary's heat is critical.
More than half of SR Motorsports' horsepower gains were accomplished via its complete underdrive pulley kit. Three undersized pulleys replace the stock alternator, water pump and main crank pulleys, and are 45 percent lighter than the pieces they replace. Made of hard-anodized billet aluminum, the undersized water pump pulley helps reduce the risk of water pump cavitation at high rpm. Cavitation occurs when the pump's blades rotate so quickly that the water is aerated and the volume of coolant pumped actually decreases when it is needed most.
This is an ideal mod for those who frequently access the high-rpm meat of the Renesis powerband for extended bouts in situations like track events or road racing. Underdriving the alternator reduces parasitic losses, but RX-8 owners with gazillion-Watt stereos who need all the electrons may want to stick to a stock pulley. SR claims just the pulley kit provides an 18-hp gain at the wheels.
SR installed its own 9.75-pound aluminum flywheel that, in addition to freeing up horsepower lost to substantial stock rotational mass, allows the driver to more quickly access the bikelike powerband. A powerplant frame, connecting the transmission to the rear differential, is part of the reason rear-wheel-drive Mazdas like the Miata, RX-7 and RX-8 are known for their excellent dynamics.
Using experience garnered from its work with the third-generation RX-7, SR Motorsports created the Heavy-Duty Powerplant Frame for the RX-8. The stock aluminum piece is gusseted, boxed and otherwise modified to increase rigidity and strength.
Although RX-8s come with a limited-slip differential from the factory, SR Motorsports claims the stock unit has been known to fail when engine output swells or the drivetrain gets shocked. The RX-8, as a result, received a 1.5-way clutch-type differential from Mazdaspeed. This is the same unit employed by RX-8 racecars and is more aggressive, in addition to being more reliable.
With Mazda turning the suspension calibration dial on the RX-8 more toward commuting comfort than back-road slamming, the Mazdaspeed spring-and-shock setup on this car firms it up like Botox. Upgraded stock-type Mazdaspeed dampers control slightly stiffer springs that lower the car approximately 1 inch.
SR Motorsports installed 1mm larger adjustable ICR anti-roll bars front and rear and fitted its own aluminum end links with Heim joints and chrome-moly hardware. SR's carbon-fiber and aluminum strut tower braces shore up both ends of the car; the front brace is triangulated to the firewall.
Brakes remain stock with the exception of Mazdaspeed pads in the front to keep up with increased power and sticky rubber.
Bridgestone Potenza S-03s (255/30-19 front, 295/30-19 rear), pack voluptuous fenders with big stick. Lips that would make a camel blush define the Axis Super Mesh wheels, 8.5 inches wide up front and 9.5 inches wide in the rear, and echo the sinister lines of the Mazdaspeed front bumper.
Fitting the abundant rollers in the front, however, meant shaving metal off the stock single-piston caliper. Lockhead also added the Mazdaspeed rear wing, a happy medium between functionality and flash. The car wears SR's billet-aluminum fuel-filler door and rear rotor emblem. Changes in the interior are limited to SR's titanium shift knob and billet-aluminum emergency brake handle.
Balance is good. Between street crawler and track ass-hauler, between nice and rice. The SR Motorsports Mazda RX-8 walks that middle line with functional, well-thought-out and executed modifications that serve to enhance the attributes of a successful, proven and overwhelmingly popular package.
SR Motorsports RX-8EngineEngine Code: Renesis 13BType: Two-rotor Wankel External Modifications: SR Motorsports GT-4 kit (cold-air ram intake system, billet-aluminum power pulley kit, stainless high-flow catalytic converter, 63 mm stainless-steel cat-back exhaust system
DrivetrainLayout: Longitudinal front engine, rear-wheel driveDrivetrain Modifications: SR Motorsports short shifter, SR Motorsports 9.75-pound flywheel, Mazdaspeed clutch-type limited-slip differential, SR Motorsports Heavy-Duty Powerplant Frame
SuspensionFront: Mazdaspeed dampers and lowering springs, ICR 28 mm anti-roll bar, SR Motorsports adjustable end links, SR Motorsports triangulated upper braceRear: Mazdaspeed dampers and lowering springs, ICR 18 mm anti-roll bar, SR Motorsports adjustable end links, SR Motorsports upper brace
BrakesF: Mazdaspeed pads, calipers machined to clear wheelsR: Stock
ExteriorWheels: 19x8.5-in. w/30mm offset (F), 19x9.5-in. w/35mm offset (R) Axis Super MeshBody: Mazdaspeed front bumper and rear wing, billet-aluminum gas door and rear rotor emblemTires: 255/30-19 (F), 295/30-19 (R) Bridgestone Potenza S-03
InteriorSR Motorsports titanium shift knob and billet aluminum emergency brake handle