Surprise Performance: Fast Cars With Suspect Horsepower Ratings

1. Buick GNX

The ’80s were the dark ages of muscle cars and American performance, but there were a few bright moments. One of the cars that restored faith in muscle car movement in the ’80s was the mighty Buick GNX. The story of this model is an interesting one. Back in 1982, Buick started experimenting with turbocharging its line of standard V6 engines. The results were satisfying, so engineers got permission to develop a performance version with better acceleration figures. Soon there was a Buick Grand National with 175 HP, which wasn’t impressive but was a start.

In the next couple of years, the Grand National got a bigger engine and more power, jumping from 175 HP to 200 HP and finally to 235 HP. With those numbers came the acceleration times of under six seconds. Those black Grand Nationals were quick cars. But in 1987 came the ultimate version Buick called the Grand National Experimental, or GNX for short. It featured the same 3.8-liter turbocharged V6 but with 275 HP and 0 to 60 mph times of 4.7 seconds. Lots of car enthusiasts claimed the GNX produced at least 300 HP since it was extremely fast. At that moment, Buick GNX was the fastest accelerating production model in the world. At $29,000 it wasn’t a bargain, but there is a widespread legend about owners who paid the lease on these cars by street racing them for money.