TOKYO — Nissan has officially refuted suggestions that cheating might have been involved during its testing of the 2009 Nissan GT-R at the Nürburgring Nordschleife this year. The carefully worded document from Tokyo responds to rumors that Porsche was unable to duplicate the GT-R's 7:29 effort in its own testing of a car this summer.The Nissan release notes that the GT-R set what was then a new lap record for production sports cars of 7:29 on April 17, 2008, during customary performance and durability testing. The car met production specifications in every way, had been equipped with production-specification Dunlop SP Sport 600 DSST CTT tires and had been driven by professional racing driver Toshio Suzuki. The car carried 110 pounds of data and video recording equipment. An official announcement was made in June.Nissan notes that the test was observed by Best Motoring, a leading Japanese car magazine, and was conducted according to the Nürburgring test protocol for lap times established by Sport Auto, a leading German magazine. Nissan further says that it still has the tires used for the test.The company says it's aware that other automakers have purchased examples of the GT-R for evaluation. It notes, 'Like all GT-R customers, we recommend than any automaker buying a GT-R follow the recommended run-in procedures, service schedules and maintenance to ensure the maximum performance from the car. In addition, we offer performance driving courses for prospective and current GT-R owners to help them get the best performance from their car. We would welcome the opportunity to help any manufacturer with understanding the full capabilities of the GT-R.'Apparently this whole saga began last May, when a member of Porsche's Nürburgring development team was overheard at a social establishment near the track rather loudly expressing his skepticism of the GT-R's ability to surpass the Porsche 911 Turbo's speed at the Nordschleife. Just a few weeks ago under similar circumstances in Verona, Italy, for the introduction of the Porsche 911 Targa, the same person repeated his thoughts in the company of members of the Australian press.Our sources have since learned that Porsche purchased a GT-R in America soon after the car's official introduction and quickly air-freighted it to Germany ($40,000 is usually the tab for such an exercise). Some time later, members of the Porsche crew at the Nürburgring brought the car to the Nissan development shop near the track and explained that they seemed to be having a little trouble with it. Kazutosi Mizuno, chief vehicle engineer and chief product specialist for the GT-R, happened to be there and — since all the Nürburgring development teams for various manufacturers are really one big family of friendly rivals — happily agreed to help them.Porsche's GT-R had something over 3,000 miles on the odometer. Its tires were in tatters. The brakes were terminally toasted. None of the fluids had been changed. Mizuno inquired whether the transmission had been recalibrated following the recommended 1,200-mile break-in procedure as specified in the owner's manual. It had not. Mizuno provided new tires and new brakes, changed the fluids and recalibrated the transmission. And then he carefully explained the driving techniques that are required to help the GT-R do its best (as a former race engineer in charge of Nissan's effort at the 24 Hours of Le Mans, he knows his stuff) and sent them on their way.It seems Porsche was no more successful afterward, and now the testing season at the Nordschleife has concluded as winter weather approaches. Our Nissan sources tell us that the whole episode is highly humorous, especially as Porsche declines to describe its own testing protocol for Nordschleife laps. When spring arrives, we'll see if there are any mysterious German students in Nissan's performance driving schools for GT-R owners.Inside Line says: Here's more proof that high-performance cars can make even engineers from the world's most sophisticated car companies act like scruffy teenagers in high-school auto shop. — Kelly Toepke, News Editor