Under the hood of the recently-updated Bentley Continental GT Speed lurks a 6.0-liter, twin-turbo W-12 engine good for some 625 horsepower. By anyone’s standards, that’s a significant amount of output, even when it has to propel a car that tips the scales at over 5,000 pounds.

It’s enough horsepower, in fact, to deliver a 0-60 mph time of 4.0 seconds, and a top speed of 205 mph, which makes the new Continental GT Speed the fastest production Bentley ever built.

As Pistonheads points out, “fastest” is not the same as “most powerful,” since that title would go to the 2009 Supersports, which came with 630 horsepower. Based on their conversation with a senior Bentley powertrain engineer, the current W-12 engine is apparently capable of much higher output.

Speculation is that the new Supersports model could get as much as 650 horsepower, but only if Bentley can ensure engine durability at the upped output. It’s engine testing regime is the stuff of nightmares for mechanics and engineers, but it ensures that any component failures won’t be mechanical in nature.

One test applied to the W-12 engine involves running it at full throttle for 100 hours, then repeating the process three more times (which simulates 20,000 miles at 200 miles per hour). Another test takes the engine to redline, 100 times, within 30 seconds of a -10 degree Celsius (14 degrees F) start up.

While we admire Bentley for putting its engines through such rigorous testing, under no circumstances do we recommend trying this at home, no matter what’s parked in your garage.