Two days ago, YouTube user AutoAvanti shared a video featuring her 2017 Alfa Romeo Giulia Quadrifoglio undergoing several tests on a dynamometer. The purpose of the video was to reveal the true power output of the vehicle. According to the Italian manufacturer, the factory specifications for the Giulia Quadrifoglio’s 2.9-liter twin-turbo V6 engine indicate it produces 505 horsepower, all directed to the rear wheels.
The highest power measurement recorded during the dyno tests was 392 horsepower, which falls short by 113 horsepower from Alfa Romeo’s rated output (which is typically measured at the crankshaft). It’s important to note that every dyno reading accounts for some level of drivetrain loss, a factor that varies based on the type of dynamometer used and the vehicle’s driveline configuration.
In general, a typical drivetrain loss for a two-wheel drive vehicle like the tested Giulia is about 20% of the factory-rated power. In this case, 20% of 505 horsepower equals 101 horsepower, which aligns with the expected range of drivetrain loss. Additionally, the Mustang Dyno utilized for the tests is known for offering conservative power readings.
Ultimately, it’s clear that Fiat Chrysler Automobiles (FCA) is not underreporting the performance of this engine, a practice that has been observed with some German car manufacturers in the past..
