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Fermi Problem Friday - Car Week Edition

The Horsepower Wars are back on. No one knows how far it will go, but is there a limit to how much horsepower you can really use on the street?



Back in the muscle car days of the late 1960s and early 1970s, a battle erupted among the major US car makers. The ammunition they used was engine size and the prize was massive horsepower. Previously, few manufacturers saw any reason to build cars with more than 150 horsepower. But by 1969, you could pick up a stunning array of vehicles with optional engines putting out nearly 400 hp, and a few that went as high as 425 or more.

The Horsepower Wars came to an abrupt end with the fuel crisis of the mid 1970s, raising gas prices to sky high rates of $0.50 a gallon or more (it was a lot back then, trust me). As if that wasn't bad enough, the government violated basic economic principles by instituting a disastrous price control and fuel rationing program, which meant weekends wasted sitting in line to fuel up.

Don't ask me why, but the Horsepower Wars are back, despite gas prices that perpetually threaten to leap up toward $5.00 a gallon. And power is reaching higher levels than ever. The retro styled Ford Mustang, Dodge Challenger, and Chevy Camaro all come in versions with 400 horsepower or more at surprisingly reasonable prices, and close to 500 horsepower if you're willing to pony up a bit more cash.

Only a few years ago, the cheapest performance cars typically cost about 100 per horse. That is, a 200 hp car cost about $20,000, and a 300 hp car cost about $30,000. Today, you can have your choice of Mustang, Challenger, or Camaro for only $75 per horse, for 400+ hp of muscle costing right around $30,000 and 500 hp monster machines are available at around $40,000.

So here's the Fermi question of the week - as power becomes perpetually cheaper, how much horsepower is too much? Put another way, what's the most horsepower a typical street car can use effectively?

Answering the question requires LOTS of assumptions. Of course, as long as you make reasonable estimates, you should get a reasonable answer. Tune in on Tuesday to see my attempt at the high hp Fermi problem.

-Buzz

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