Somehow, we doubt that dyno numbers are quite as important to individuals who are in the market for a new BMW 7 Series as they are to someone shopping for a new Camaro, GT-R or Corvette. As casual observers, though, we'll always be interested to see what happens when a twin-turbo V8 from Bavaria's finest gets a chance to stretch its legs a bit. Fortunately, we're not disappointed with the results.

BMW rates the 4.4-liter twin-turbo V8 at 400 horsepower at 5,500 rpm and 450 pound-feet of torque at 1,800 rpm as it leaves the factory. According to the lucky crew over at Inside Line, BMW's brand-new 750i managed to put down an impressive 391 horsepower at around 5,500 RPM and 434 lb-ft of torque at about 3,500 RPM. Those numbers are at the rear wheels, so drivetrain losses of around 15% must be factored in to find the true power output of the engine itself.

In other words, this engine puts out considerably more ponies than BMW claims. Interestingly, the same is true of BMW's 3.0-liter twin-turbo inline six-cylinder engine. We don't know about you, but this is an error we can forgive.

http://www.autoblog.com/2009/05/01/2...r-rated-power/

 

I wonder why does BMW (and some other manufacturers) underrate the output. Is it to fool insurance companies or gas guzzler laws?

 

Yeah I'm not sure. Why is that?

 

That is just a beast but its not like the last 750 was a slouch.

 

Time to go to a BMW dealer and 'act' interested for a test drive

 

VERY impressive!

 

yeah and the fact they aren't really into the HP wars like MB is/ was.