The result may surprise you.
If you're a regular reader at CarBuzz, you may have noticed that we're slightly smitten with the Alfa Romeo Giulia Quadrifoglio. Just slightly. The Quadrifoglio represents the Italian manufacturer's latest attempt to make a mark in North America – and what a comeback it is. With a glorious, all-aluminum 2.9-liter twin-turbo V6 producing 505 hp and 443 lb-ft of torque sent to the rear wheels, it's Alfa Romeo's most serious attempt yet to outclass its German rivals.
But how much horsepower does this super sedan actually produce in the real world? To find out, YouTube channel AutoAvanti hooked the Quadrifoglio up to a dyno in the latest installment of its "Owning an Alfa Romeo Giulia Quadrifoglio" series. The result may surprise you.
According to the Mustang dynamometer, the Giulia Quadrifoglio measured at 392-hp and the torque reading was 389 lb-ft – that's 113 less ponies than Alfa Romeo claim. Of course, you're always going to get some drivetrain loss in a dyno reading, and the uploader points out that the Mustang dyno used often gives conservative ratings, so that's likely to be the case here. Users have also requested the Quadrifoglio to be tested with an all-wheel-drive dyno, but this isn't possible according to AutoAvanti. When tested on a two-wheel dyno, the Quadrifoglio goes into limp mode, so the four-roller version was the only suitable dyno for the job.