UPDATE: Ford offered the following statement on 2020 Shelby GT500 horsepower:
"The all-new 2020 Mustang Shelby GT500 is the most powerful Ford production vehicle ever with 760 horsepower certified to SAE dynamometer standards. Individual dyno testing is subject to many variables, including the dyno, air temperature, elevation and more."
We pressed further since the DCT is a brand new aspect to Mustang performance. Ford further explained that, in some conditions, the DCT actually achieves no significant power loss. A Ford spokesperson explained it this way:
"The segment-first dual-clutch transmission in the all-new 2020 Ford Mustang Shelby GT500 is designed to carry full engine torque when either of its clutch packs are fully engaged. The result is no measureable loss of power at the clutch itself. However, there are numerous conditions where the clutches slip by design to achieve different engagements for drive conditions."
Ford didn't offer any estimates for overall driveline loss from the DCT, but it certainly suggests the industry-standard 15 percent might be high for this gearbox.
The 2020 Ford Mustang Shelby GT500 produces 760 horsepower, or does it? Now that production cars are finally getting into the hands of buyers, we have what appears to be the first private-owner GT500 dyno pull, or at least, the first one on camera. The clip comes from Speed Phenom on YouTube, and there’s no other way to say it – with 705 horsepower at the wheels, the run suggests the GT500 is underrated by a wide margin. However, let’s not jump to conclusions just yet.
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We’ve been down this underrated-horsepower road before, specifically with the infamous C8 Corvette pull done by Motor Trend that suggested the car was significantly more powerful than Chevy’s 495-hp factory rating. Dyno error was the culprit there, and it's possible an error occurred here as well though for now, we’ll assume that all the variables were entered correctly. We also assume that this car is, in fact, bone stock as the video advertises.
That said, using the commonly accepted 15 percent parasitic driveline power loss, a 760-hp GT500 should develop around 650 hp at the wheels. As such, this dyno session suggests the GT500 actually makes around 825 hp, which would be remarkable. Furthermore, there is notable evidence that Ford has a history of underrating at least some Mustang models – the infamous 2003-2004 supercharged SVT Cobra was widely believed to make 425 hp at the crank versus the official 390 hp rating.
Gallery: 2020 Ford Mustang Shelby GT500: First Drive
Are we going on record, then, as saying the new GT500 is underrated by a full 65 hp? Not remotely, for a few notable reasons. First off, the Shelby's "dry" wet-clutch DCT could beat that 15 percent standard. Power loss would have to be around 8 percent for the numbers to match up, which admittedly is a very tall order. Still, we don't know just how efficient this gearbox is, so that's certainly an unknown variable.
There also could be differences in the rating process used by Ford versus what you'll find on chassis dynos, and the dynos themselves aren't an exact science when it comes to gauging crankshaft power. Results can vary between different dyno designs, and of course, atmospheric conditions can affect engine power. We must also acknowledge that operator errors can happen, and yes, Ford may well have underrated the GT500.
A 65-hp difference at the crank – while significant – isn't extreme. A dyno that reads a bit high combined with a DCT robbing a bit less engine power could cut that number in half. And honestly, we'd have no trouble at all believing Ford's supercharged 5.2-liter V8 makes 30 more hp than advertised.