I vividly remember the first weeks spent driving my one and only brand spanking new car. It was a 1986 Dodge Lancer Turbo five-speed that I custom-ordered with all the futuristic kit: digital gauges, trip computer, and the "a-door-is-a-jar" lady. I took delivery with only a single "2" glowing in the odometer and babied it for the recommended break-in period. The magic number (600 miles) blinked as I eased up to a stop sign. To celebrate its matriculation to automotive adulthood, I launched with a wide-open-throttle clutch-drop wheel-hop flourish. That 2.2-liter turbo ran like a German train for the next 150,000 miles without burning oil.

So you can imagine how my eyebrows arched as I recently read a Web site advocating a radical break-in procedure that involves lots of big throttle openings within the first 20 miles of operation in order to boost performance and improve durability.

Motoman's logic (mototuneusa.com) is hard to dispute. He notes that machine tools leave ridges and peaks in new or freshly honed cylinder bores, and the piston rings polish them off while conforming to the precise shape of the cylinder. He asserts that at light throttle openings there's insufficient cylinder pressure to force the rings out into full contact with the cylinder wall, which leads to uneven wear that allows exhaust to blow by the rings and contaminate the oil. The site suggests that improved compression can boost power by between two and 10 percent.

Motoman claims his procedure works on all four-stroke engines, though he admits that most of the 300 engines he's tested power air-cooled motorcycles and snowmobiles. Could beating on a brand-new car engine boost its performance? Are manufacturers simply hesitant to recommend a full-throttle break-in out of fear of drivers exceeding speed limits?

For answers, I rang up long-time GM engine guru Dave Lancaster, and he agrees that in smaller, low-cost air-cooled engines (which expand and contract more as temperatures change) such a technique might indeed pay off. But the microfinished bores, high-tension rings, and precision-build tolerances in today's automotive engines yield excellent ring sealing from new, so any change in power output attributable to such a radical procedure would be miniscule if measurable at all. He notes that power and fuel economy generally improve throughout the break-in period as friction diminishes in all moving parts. Ford's engine durability specialist Mike Herr concurs with all the above as do the engine R&D experts at Honda.

Motoman counters by arguing that the fine machining and high-precision build quality of modern engines serve only to shorten the window of opportunity to "seat the rings," making it even more important to do the heavy-duty accels right off the bat. But if his procedure works, why don't manufacturers perform it in the plant on a dyno, especially on performance engines like the handbuilt Corvette LS7 and supercharged Northstar? They would, but Lancaster and Herr confirm the only engines that get such treatment are those undergoing torture-testing during development to ensure that the Motomans of the world won't ring up big warranty claims.

My final problem with these Web claims is that they seem unverifiable. Since no two engines--especially smaller, cheaper ones--produce equivalent power fresh off the assembly line, it's impossible to attribute small performance differences to a break-in procedure. So it's your choice: Follow your owner's manual recommendations (which usually entail gentle driving at varying engine speeds and no towing for between 300 and 1000 miles); or pursue Web logic in hopes of gaining a racer's edge of added performance.