It could have been worse. The campaigning Senator

, in a Missouri town-hall meeting last July, could have told us to cut out the jack-rabbit starts.

What he actually said was hardly more insightful: “. . . we could save all the oil that they’re talking about getting off drilling if everybody was just inflating their tires. And getting regular tuneups.”

The bloggers and the mainstream media pounced on the tire-inflation detail like chickens on a cricket, and mostly they defended his claim by citing Googled-up “experts” who promised gas savings up to 10 percent. As usual, the froth was deep and the math fanciful. Only one guy got the numbers right, and I’ll return to his insight down the page.

As for Obama’s “regular tuneups,” no one blew the whistle on that one. You can still buy a tuneup. You can buy a kick in the butt, too, and it will save just as much gas on any car built in the last 13 years or so.

Tuneups and I go way back. They were a ritual as regular as springtime up through the 1960s: new spark plugs, new ignition points, new condenser, set the timing, clean the carburetor, fuss with the automatic choke. Every 12,000 miles, you’d take Ol’ Bessie into the shop. You’d get her back with greasy handprints on the steering wheel and a bill for 30 bucks.

Every 12,000 miles wasn’t often enough, though, if you really wanted your machine to

run.

My , with its 11.25-to-one-compression-ratio 327, liked fresh plugs every thousand miles. The valve lash sounded pretty ragged after 5000, too. Probably all of those visits to the 6000-rpm range had something to do with that. High-revving V-8s in those days had dual points, so we had to set the dwell just right. I haven’t seen my dwell meter since the last millennium.

Ignition points are now answers to trivia quizzes. All

cars became pointless by 1976 as they changed to breakerless ignitions, and the rest of the industry quickly followed. By 1981, all Ford models had computer-controlled fuel metering and spark advance; the others were only a few minutes behind. The carburetor was near extinction by 1987, replaced by fuel injection. By 1995,

, and

’s Northstar V-8 recommended no spark-plug change for 100,000 miles. Changing plugs is now about all that’s left of the tuneup as we knew it, and most mainstream models recommend the first change at some mileage over 100,000 (102,000 for Dodge, 105,000 for

, 120,000 in the case of

).

The term “tuneup,” Wikipedia reports, dates back to the tuning of an engine’s spark timing, which hasn’t been adjustable on most cars built in the last several decades. The term has survived, it says, as a catchall for a general-maintenance procedure; think belts and hoses. Our new president campaigned on a 10-year-plan to wean us from Middle Eastern oil. Changing plugs every six or seven years when you roll over another 100K won’t get us there.

Defenders of the new president argue that even the EPA ( ) agrees that tuneups improve mileage by four percent. It actually says, “Fixing a car that is noticeably out of tune or has failed an emissions test can improve its gas mileage by an average of four percent . . .” Can we agree that tune-upping our way to energy independence is not a serious plan?

As for tire inflation, I’m a believer, and I’ve kept a tire gauge at the ready in my briefcase for 20 years. While our Tech Dept. was evaluating tire-pressure effects on mileage [“

,”

], I ran my own tests in a

, repeating a 29.5-mile loop between nearby towns at exactly the speed limit as it changed from 40 to 55, then 65. Dropping all four tires 6 psi from the recommended 35 cost 1.1 percent in mpg over the loop, less than I expected. Trying for a worst case, I lowered all of them 15 psi below recommended, enough to make the steering rubbery and the ride carpet smooth. Mileage dropped 3.9 percent below the 36 mpg recorded at recommended pressure.

I would expect tires of different profiles to respond differently to pressure changes. My variable-speed test ran on high-profile Michelin Latitude Tour P235/70R-16s. The Tech Dept.’s constant-speed test used medium-profile Michelin Pilot HX MXM4 P235/55R-18s. Still, our results are close enough to confirm that we can’t inflate our way to energy independence, either.

Earlier, I said that only one voice in the public debate got the numbers right. That was our own editor-in-chief Csaba Csere in a video clip viewable at

. He pointed out two holes in Obama’s logic.

Probably is close enough for government work when it says the loss in mpg per psi of underinflation is 0.3 percent. But that’s for all four tires. To save three percent of fuel as the new president proposes, all four tires of every vehicle in the country would have to be underinflated by 10 psi. That’s not likely.

Next point: Even if you could save three percent of the nation’s gasoline with the tire pump, that doesn’t save three percent of crude oil. Only 43 percent of crude goes to gasoline, according to the Department of Energy. Even if you could save one percent of gasoline by properly inflating tires—an optimistic scenario—that would save less than half a percent of our crude-oil needs.

Pulitzer Prize winner Dan Neil of the Los Angeles Times,

never a tidy guy in matters of science,

decries “the eagerness to put Obama’s remark through the meat grinder of literalness.” But it will take more than Obama’s famous rhetorical flourishes to wean us from Middle Eastern oil in 10 years. It will take a serious plan.

Article source: http://www.caranddriver.com/features/09q1/tune-upping_our_way_to_saving_gas-column