The horsepower race is on. Automakers are bragging about the horsepower of their new cars, reviving the spirit that brought us the muscle cars of the sixties.
Saab could brag too: The 1985 Saab Turbo develops 160 horsepower, more than enough for rubber-burning, necksnapping acceleration.
But in Sweden, at the Saab Car Division's research center, sheltered from Madison Avenue's influence, Technical Director Gunnar Larsson shares with us Saab's iconoclastic view of the horsepower race: "Horsepower is of minor interest," he said
This comment is surprising, coming as it does from the automaker that spearheaded today's generation of highperformance cars.
According to Mr. Larsson, the maximum horsepower that an engine develops is not the crucial factor when assessing performance. "The driver's impression depends on torque," he said.
Torque, expressed in foot-pounds, is the force with which the engine rotates the wheels. It is the engine's true muscle. Power, on the other hand is an abstract concept: scientists define power as the amount of work that an engine can do in a given time interval.
The Myth About Horsepower
The confusion in peoples' minds comes from the words. "Everybody knows the word power," Mr. Larsson said. "Power is a magic word, synonymous with control and authority. Torque is more of a mystery."
In spite of what the public thinks, "Horsepower only measures performance in the showroom; torque measures performance on the road," Mr. Larsson said.
Drivers shopping for high-performance should learn how torque relates to their driving. The best way to understand what torque does is to compare two cars with identical horsepower but different torque ratings.
The car with less torque doesn't feel as strong. Acceleration is weak until the engine approaches its top speed. Then power erupts in a brief surge: It's only with the engine revving close to its limit that acceleration matches the high torque car. This is acceptable in competition, but not practical in everyday driving.
The second car, with high torque, accelerates readily at all engine speeds. It responds quickly to the demands of the driver. A slight pressure on the accelerator propels the car ahead. There's little need for downshifting to pass
another car and, overall, it's a satisfying feeling.
Torque gives a car the gutsy and responsive feeling driving enthusiasts look for in their exotic machines," Mr. Larsson said.
Large Engines Not Needed
it is common belief that only large engines develop high torque. Saab's third generation turbocharged engine, with its high-technology 16-valve configuration and intelligent use of electronics, shows this is no longer true.
The 1985 Saab Turbo develops 188 foot-pounds of torque, matched only by cars with larger engines. It has the performance of a big V-S but keeps the efficiency of a 2-liter four-cylinder fuel-injected engine.
The new Saab develops its highest torque at a low engine speed of 3,000 rpm, giving it extremely good acceleration in top gear, already from speeds of 50 miles per hour. "More than high horsepower, torque is the reason for the Saab Turbo's high-speed passing ability," Mr. Larsson said.
According to Mr. Larsson, no other car in the 2-liter class develops as much torque as the 1985 Saab Turbo at such low engine speeds. "We were the first to offer turbocharging in a family car," he said. "It's no surprise that we continue to lead the pack."