It is possible to have power, but it must reach the ground.
Motor1.com doesn’t usually do instrumented vehicle performance testing, but Driver has done it for decades. BMW released its mildly updated 5 Series with the M550i xDrive, which packs a 523-horsepower (390 kW) twin-turbocharged engine under the hood. BMW claims it can reach 60 mph in just 3.6 seconds. However, the C&D group found that it is much faster. Eventually, so did BMW. We’ll get to that later.
The magazine’s tests last year could only manage a 4.1 second sprint to 60 for the Bimmer. Although there are many factors that can impact performance, it is difficult to measure a half second. A second set of tests was conducted to confirm that the time dropped to 3.9 seconds. Although it’s not a huge margin, we are proud to give credit where credit is due. They were proud to have strong performance stats and asked BMW to send them another M550i for their testing. But it didn’t happen for some nefarious reasons.
BMW discovered a small technical issue that affected both the M550i xDrive and 540i xDrive models. A communication error between the engine and stability management system causes a slight drop in boost pressure after the beans are given to Driver. It’s not that all the horsepower isn’t there. The cars aren’t as punchy off the line now than they should be. It’s not that 60 mph is possible in any car, but it’s slow for a large sedan.
Although it is not clear whether BMW knew about the problem before testing began, an over-the air software update to address the issue is expected sometime this summer. Motor1.com reached out to BMW for confirmation and additional information. We’ll update if we have more information.