Robb Report - 'Pedal To The Metal'

December 2004

RADICAL SR3 SUPERSPORT

When trackday enthusiasts modify their everyday cars for weekend fun, they often face a quandary. The penalties for marginal performance gained on the track typically include compromises on both street usability and collector value. And so many drivers have decided that the best route to ultimate track performance is acquiring a dedicated racing car such as the Radical SR3 Supersport.

A sports racing car has a purity of design. There are no ride/handling compromises, no styling exercises to enhance marketing appeal and no comfort and convenience options. Without having to retain parts, forms or measurements from a production-based vehicle, the sports racing car designer is free to pursue speed through innovation. The British have long been the dominant manufactures - if not the inventors - of small displacement sports racing cars and they have a thriving industry. Among these manufacturers is Radical Extreme Sports Cars, manufacturer of the SR3.

The SR3 is a two-seat, open-cockpit, 1,100-pound sports racer, built around a rigid tube frame and suspension that uses 'floating' coil shock units and an anti-roll linkage to ensure a tenacious grip on the road. A dedicated racecar, the Radical has had success in SCCA C sports racing classes and endurance events here and in Europe, while becoming the darling of trackday participants. To date, more than 400 of the type have been delivered.

The engine comes from the 1300cc Suzuki Hayabusa sportbike, a twin-cam 16-value fuel-injection four producing over 170bhp. Enlarged to 1500cc it produces 225bhp, giving the Radical sports racer a power-to-weight ratio of nearly 450bhp per ton of neck-straining, eyeball flattening performance. The engine and its sequentially shifted gearbox are mated to a quick-change final drive and Quaife torque-biasing differential. This engine/transmission package is powerful, extremely reliable and simple to maintain.

The performance is not like that of the best track-worthly road cars, such as the Ferrari F360 Stradale, Porsche GT2, Viper or Corvette Z06. It is of a magnitude higher. In a six-lap demonstration as the Mazda Raceway Laguna Seca, John Morris, proprietor of Anaheim dealer Radical West, gave this writer a fine demonstration of the difference between a purpose-built sports racer and any modified road car. Starting, behind a line of competently driven Vipers, Corvettes, an E360 and a Porsche GT2, the Radical lapped the entire field in only five laps, giving the 225bhp Radical an advantage of more than 25 seconds per lap while carrying a passenger weighing 170lbs. Yes, the car could have gone faster. Fast enough in fact for the Radical SR3 to hold the lap record at the legendary, ultra- long and fast Nürburgring Nordschleife circuit. In short, to challenge a Radical with a 500bhp road car would be to walk into the gunfight armed with nothing more than a basket of fresh fruit.

Although lightweight and powerful, the Radical's purpose is not acceleration or straight-line spee. Mick Hyde, co-founder of Radical Extreme Sportscars, says:
"The fun is going around corners. The car is designed to carry more of its straightaway speed into the corners, and its design allows even midcorner gear changes without disturbing the car"

Going from a 3300-pound production car with standard H-pattern shifting and a driving position that places the eye more than a yard above the road to a 1100-pound sequential shift, 2-foot-high sports racer on slick race tires is not something to be taken lightly. Unless you have substantial experience with those manic shifter karts, driving a Radical will be a learning curve.

I'm ready for the challenge and step into the Radical one leg at a time over a wide composite bodywork. The enveloping seat and pedals are adjustable with wrenches, and it takes only a few minutes to fit the car to my compact physique. With ignition and fuel pump switches on, I press the starter button and hear the familiar rip of a Suzuki sportbike engine. Throttle response is immediate, and the clutch effort is light as as I select first gear. With little clutch slip, the Radical drives off happily, bereft of bucking, chattering or other untoward behaviour.

Resisting the urge to short shift, I accelerate out of the pit lane, accompanied by an F1-like shriek of the engine and robust acceleration. Hitting the middle LED (about 8000rpm) on the ribbon-style tach, I lift the throttle slightly and tug the shift lever without benefit of the clutch. The gear engages instantly, and I am back on the throttle, ready to shift again and again and again.

Approaching the first turn, I brake too early, employing the clutch to downshift, blipping the throttle and palming the shift lever forward one gear at a time.... 5, 4, 3, and back on the throttle. The Radical's bodywork, wing and undertray produce aerodynamic downforce equal to more than half the car's weight, amplifying the already prodigious mechanical grip and increasing cornering speeds. The trick here is to carry enough speed into the corner to produce the downforce. With the Radical, the faster you go through the corner, the more downforce available, allowing increased cornering speed, which increases the downforce. The faster you go, the faster can you go.

The Radical puts the power down well, and once in the corner the throttle can be fed in quite rapidly, resulting in a smooth controlled drifting the slower corners and neck-straining force in the faster ones. As soon as the car begins to accelerate, upshifting begins and the next corner approaches much sooner than anticipated With powerful American-manufactured Wilwood racing brakes, the Radical diminishes speed with far more authority than any production car, and I heel/toe downshift in preparation for the next application of power.

Unlike shifter karts and stiffly sprung production-based racers, the Radical's suspension is quite compliant and does not beat or bruise its driver. Aside from subjecting the operator to lateral g's and vision-blurring acceleration, the Radical is relatively comfortable when going quickly, and it has a forgiving nature.

Moving from a quick road car to the sports racing Radical is immensely rewarding. The chassis can be adjusted to meet a driver's improving skill level, and the power can be increased easily if you feel it is necessary. Its quality of construction is of a high order and service is a simple affair. Designed for rigorous use in both sprint and endurance races, Radicals are known for their strength, reliability and safety.

For busy weekend racers, Radical west has an 'Arrive and Drive' program. This allows Radical owners to have their cars transported and maintained at the events by Radical West personnel, fuel tyres and maintenance chores are tended to and all the drivers has to do is attend the driver's meeting, suit up and drive.

Jan Morgan