More horsepower, better fuel efficiency

If you follow Environmental Protection Agency (EPA) rules, restrictions, and proposals, you’re already aware that it has mandated a corporate average fuel economy (CAFE) of 54.5 miles per gallon by 2025. Carmakers have been moving in this direction for many years, reducing weight where possible, for example by using aluminum parts or high-strength steel components where they once used common steel. As reported in the August issue of Popular Science, they also are using every trick in the book to coax a little more performance out of the powerplant.

Of course this is nothing new. With apologies to all the GM and Chrysler fanatics in the reading audience, it’s a reminder that nearly everyone under the sun who wanted a Ford® Mustang® in the 1965-1968 era wanted the venerable 289-cu.-in. V8 engine. At 200 horsepower, the 289 left the standard Mustang engine, a 170-cu.-in. straight 6 that developed 100 HP, in the proverbial dust. A later offering, a 200-cu.-in. straight 6, at 120 HP, wasn’t a big improvement.

But man, oh man, did Ford do a lot with the 289! In addition to the 200-HP version, it also offered an upgraded 289, outfitted with a four-barrel carburetor and a higher compression ratio (10.0:1 rather than 9.3:1), for 225 horsepower. A third option was Ford’s “HiPo” variant, which had different camshaft timing, higher compression ratio (10.5:1), a dual point, centrifugal-advance distributor, less restrictive exhaust manifolds, and a carburetor that moved air at 595 cubic feet per minute (up from 480 CFM). The result: a kick in the seat of the pants at 271 horsepower.

And then came Carroll Shelby and his GT350. His work—a larger carburetor still, different exhaust headers, and a few other goodies—pushed the output to 306 HP. An optional Paxton supercharger added about 80 HP, nearly doubling the output of the standard 289. Makes your blood boil, doesn’t it?

This was long before the 1973 oil crisis, America’s long-decried dependence on foreign oil, and gasoline costing $4.00 per gallon. According to the Dept. of Energy (which didn’t even exist at that time), gasoline in the 1965-1968 timeframe was the equivalent of $1.75 per gallon. These days we’re bombarded with fuel efficiency ratings when looking at automobiles, but I wonder if anyone put any attention on it back then. Doubtful.

In the ensuing decades, much changed. Sky-high oil prices in the middle 1970s and early 1980s created an economic problem; a dwindling domestic supply created a strategic problem; more and more of our money flowing into the Middle East exacerbated a political problem. These days we have mandates to reduce pollution and reduce our dependence on foreign oil, and it might not hurt to reduce our entanglements in a politically volatile region. This brings us to today’s cars.

First, a caveat: Horsepower is measured differently these days. Until 1972, the Society of Automotive engineers specified the measurements in gross horsepower, or brake horsepower (which includes the parasitic power losses from the transmission, differential, and so on, simulated by attaching a brake to the crankshaft). Since then, automobile manufacturers have measured net horsepower, without the brake. Therefore, comparisons between pre- and post-1972 cars aren’t valid. Still, it’s worth looking at several of today’s cars.

The latest Ford Fiesta is equipped with a 1-liter engine. If you think that’s small, it is, considering that carbonated soda comes in 2-liter bottles; considering that it is 14 percent of the size of Ford's largest Mustang engine, the 429; and considering that one liter is the equivalent of 61 cu. in. Still, a turbocharger and direct fuel injection help it achieve 123 HP, and it exceeds 40 miles per gallon on the highway. Not bad. Approximate price: $16,000.

Next up is BMW’s 1.5-liter engine, a 3-cylinder, that develops 220 HP. Augmented by an electric motor for better acceleration, it squeezes every drop of gasoline to get 80 MPG. The drawback is that this is a luxury car with a luxury price tag, $125,000.

Mercedes has a 2-liter engine that produces 355 HP, which PopSci says is the highest output-to-displacement ratio for any engine. It’s turbocharged and it “should approach” 30 MPG. It’s in the middle of the price range at $48,000.

Oh, the current Mustang? Ford has good news if you missed the 1965-1968 era. The 2013 basic model gets 305 HP out of a 3.7-liter V6, and runs at 31 MPG on the highway. And yes, a Shelby version is available, a supercharged 5.8-liter engine that develops 650 horsepower. Now if we could just get the price of gas back down to $1.75 per gallon.