Specialty File
Southern California's San Fernando Valley is in the business of satisfying carnal appetites. According to the Los Angeles Times, about $4 billion worth of "adult entertainment" rolled out of the valley in 1999, and that amount has only grown since then. Whatever the fetish, the valley has the product.
Race Marque Systems (RMS), located in Van Nuys at the valley's heart, is in the business of building the equivalent of automotive porn stars. Specializing in modified BMWs, the company's current push is behind a series of supercharged M-motored machines it calls Superfast (M3, Z8, and the subject here, M5). The M5 Superfast is the sort of vehicle you'd order because you're already sick of waiting for the new V-10-powered M5, not thrilled with how the new 5-series looks, unused to postponing pleasure, and flush after selling a warehouse full of Jenna Jameson compilation DVDs.
The Superfast's essential element is a Vortech V-2 SQ SC-Trim centrifugal supercharger driven by a second crankshaft pulley at 1.8 times engine speed (gearing in the blower case multiplies compressor speed by another 3.60:1) and mounted on a thick anodized aluminum plate.
"SQ" is for "super quiet," and indeed, this Vortech is fairly quiet as it crams 11.0 psi of boost into the otherwise stock M5 S62 4.9-liter DOHC V-8. The pressurized air goes through a carbon-composite tube and then an intercooler that RMS describes as an "air-to-liquid charge air cooler" in the intake plenum between the two rows of air trumpets and under an RMS carbon-fiber cover. The charge cooler is in turn fed from a small aluminum radiator shoehorned into the stock M5 air dam, with water circulated by an electric pump. Eight supplementary injectors—one for each cylinder—dump in the necessary fuel, and an RMS FuelCharger controller manages air and fuel delivery and controls the bypass valve. RMS will tear into an M5's engine if a customer wants, but our tester's internals were untouched.
Exhaling from RMS headers and mufflers, RMS claims 608 horsepower at 6700 rpm for its blown M5 engine. That's a 214-hp credulity-straining leap from the 394 horses that BMW lists for its stock V-8. To go with that thrust, RMS adds its billet-aluminum short-shifter kit for the six-speed manual transmission, fits a 3.45:1 ring and pinion (stock is 3.15) and a new limited-slip differential, and upsizes the front brakes to Brembo 14.0-inch discs with 13.6-inch Brembos in the back. The suspension is dropped an inch in the front and 0.75 inch in the back, and RMS 9.0-by-18-inch front and 10.0-by-18-inch rear wheels are bolted on inside Michelin Pilot Sport 265/40ZR-18 front and 295/35ZR-18 rear tires. The owner who lent us this 2000 test car also had RMS throw in a race clutch that needs a forged-steel femur to operate.
Showing nearly 60,000 miles on its odometer, and having been subjected to regular track thrashings, this 2000 M5 had rough edges. But the structure was tight, and there wasn't a hint of slop in the steering or suspension—the just-departed E39 5-series is as good as we've always made it out to be.
With its insensitive clutch, sudden throttle, and overwhelming torque, this isn't an easy car to launch. Still, it cleaved down the quarter-mile in 12.8 seconds at 114 mph and hit 60 mph in just 4.4 seconds. Compared with a stock M5's 4.9-second 0-to-60 clocking and 13.4 seconds at 108 mph in the quarter-mile (May 2003), that's good. But it's not up to the performance of a naturally aspirated Dinan S2-M5, which did the 0-to-60 trick in 4.1 seconds and whacked through the quarter in 12.7 seconds at 113 mph (November 2002). The RMS car's better trap speed, despite being slightly behind in elapsed time, indicates that this engine's talent is top-end horsepower.
The Dinan car made it to 110 mph in 12.0 seconds; the RMS M5 gets there in 12.1. But the RMS M5 gets to 120 mph in just 14.1 seconds compared with the Dinan's 14.4, and the Superfast's advantage only grows from there. Ultimately, the RMS M5 rips to 150 mph in just 23.5 seconds, whereas the Dinan takes 25.1 seconds and a stock M5 takes 29.2. A gentler clutch and a bit more software tuning by RMS should make the Superfast easier to launch and improve its transitional part-to-full-throttle response.
The ride is barely affected by lowering the suspension, and the Michelin Pilot Sports are quiet and tenacious. The exhaust system's voice roars with perfect pitch—like the blend of a B-52H and Ella Fitzgerald. If the M5 Superfast did nothing but make that sound, the sheer wickedness could almost justify its $120,645 price (including engine, wheels, tires, labor, and a $72,645 donor M5). The supercharger system alone goes for $22,500.
Like a porn star, the RMS M5 Superfast is great-looking and fitted with aftermarket pieces. And like a porn star, it's emotionally fragile. Our repeated acceleration runs led to the fouling of at least one spark plug, and the computer went into limp-home mode. No one should be surprised that supercharged tuner cars are more temperamental than stock, and porn stars shouldn't be surprised to find themselves in the valley on a flatbed.
Race Marque Systems, 14418 Oxnard Street, Van Nuys, California 91401; 818-778-6106; www.racemarque.com.
