New Standard For Certifying Horsepower and Torque Numbers
There is always some speculation surrounding the horsepower ratings of the new cars released by automakers. It is believed that some cars are overrated, while others are underrated. The Society of Automotive Engineers (SAE) recently revised the rules for measuring horsepower and torque and introduced a new standard for certifying these numbers.
A similar movement took place in 1971, when emissions control first entered the marketplace. During this time, net horsepower ratings were introduced, which accounted for the engine wear on an alternator, vital-fluid pumps, and intake and exhaust systems. Although there was no mathematical correlation between the old ratings and the new net ratings, the standard lowered ratings by roughly 20%. The industry shifted to reporting SAE net ratings in 1971.
This latest version of J1349 (J2723) will not cut everyone’s engine ratings. The first engine certified to meet the revised standard is the Corvette Z06’s LS7, and it actually received a five horsepower increase to 505. The revision to J1349 will account for new engine technologies and reduce the opportunity for liberal interpretation. By having a neutral third-party SAE witness certify an engine’s output, automakers can help dispel doubts and win customer confidence.
The new certification standard is voluntary. So far, General Motors is the only automaker that “plans to certify every new or significantly revised engine in the future." Ford does not have any plans to certify its engines, and Chrysler is still considering whether to certify all engines or just high-performance motors.
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