A complete idiot on MBWorld by the name of Jerry Perez is spreading what you can only appropriately call fake news by stating the Alfa Romeo Giulia Quadrifoglio does not deliver on its claimed 505 horsepower output:
Touted as the AMG Beater, the Alfa Romeo Giulia Quadrifoglioís Advertised Horsepower Crumbles on the Dyno
His reasoning? This dyno graph from an article last week:
The genius writes the power crumbles on the dyno. Yes, seriously. He decides to apply a 15% correction factor which means the car should actually show 429 horsepower to the wheels and that is the basis for his claim.
Well, we can't argue with that now can we? 15% of 505 horsepower is 429. He's got us there.
At no point though does he consider that a Mustang dyno may read differently than other dynos. At no point does he consider that the 15% drivetrain loss 'rule' actually originated with the Dynojet and is used as a (flawed) rule of thumb for drivetrain losses on manual transmission cars. At no point does he think about maybe doing some basic research into the dyno type and looking at results from other cars.
Here is an example. This is a C218 generation Mercedes-AMG CLS63 with the M157 twin turbo V8 motor. It is rated at 518 horsepower and 516 lb-ft of torque. By the reasoning of Mr. Perez it should show 440 horsepower to the wheels:
OMG? What is going on here? Someone sound the alarm! Only 390 horsepower to the wheels from a 518 horsepower motor! Where is the article saying C218 CLS63 AMG horsepower crumbles on the dyno?
Brace yourself. Here comes something that will blow your mind. This is a CLS63 on a different type of dyno:
Yes, the blue line is the stock output and shows 483 horsepower to the wheels. Suddenly the CLS63 goes from not having 518 horsepower to having more than 518 horsepower. Is this magic? Do CLS63's vary by 93 horsepower at the wheels from the factory?
No. It's simply that Jerry Perez is a hack, MBWorld is run by morons who allow fanboys to spew this garbage, and the user base is not intelligent enough to know the difference.
One can simply look at the trap speed for the Giulia Quadrifoglio to see it is making its advertised output. Anyone who is going to make a claim that a car is underperforming should at least research its performance figures beforehand.
Alfa Romeo should be angry this false claim is being spread but then again they have bigger fish to fry. BoostAddict will happily correct this garbage.