What Does This Insanely Awesome Button Do?

CARS.COM — The 2014 Jeep Grand Cherokee SRT8 is home to perhaps one of the most appropriate buttons we've encountered in the vehicles of our What Does This Button Do? series. Mysterious car buttons are rarely spelled out as clearly as the Jeep's — or are as fun to use.

Related: More Buttons Demystified on Cars.com

By spelled out, we mean the whole word, "Launch," appears on the button to designate the 470-horsepower, all-wheel-drive Grand Cherokee SRT8's Launch Mode, a launch control feature. There are no acronyms or guessing with this button. What the button does is also made clearer by the awesome depiction of a drag strip's starting-line lights, aka a "Christmas tree."

Launch control is standard on Jeep Grand Cherokee SRT8 models and delivers consistent, enhanced fast starts of the high-performance, high-horsepower SUV. Launch Mode brings the engine, suspension, transmission and driveline together for fast launches from a standstill by revving the engine at a stop and launching the 5,000-pound SUV like a rocket.

To activate, Jeep's instructions say the SUV must be stopped on a level surface before fully depressing the brake pedal — while in Drive — and then pressing the Launch button. While holding the brake, mash the accelerator pedal to the floor within a half-second and the engine will rev to a predetermined rpm. Once the engine speed is up, all the driver has to do is lift the brake and the Grand Cherokee SRT8 launches perfectly every time.

Cars.com reviewer Aaron Bragman tested the Grand Cherokee SRT8's Launch Mode at the vehicle's introduction. His assessment of the button's effect on launch control and how the vehicle behaves says it all.

"Jeep rates the SRT Grand Cherokee at 4.8 seconds from zero-to-60 mph, but I discovered that this is a conservative figure: Using the SRT's onboard software and a special launch button, I was able to consistently rip off 4.5-second zero-to-60 times, and SRT engineers say that they've been able to achieve 60 mph in 4.2 seconds under perfect conditions."

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