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Friday, April 29, 2016

Hennessey Turned the GMC Yukon into an 800-HP Super SUV


Copyright © 2016 Bold Ride LLC.

Some cars you’d expect to have a lot of horsepower on hand—the 707-hp Dodge Challenger Hellcat or 730-hp Ferrari F12berlinetta, for instance. A GMC Yukon though? With 420 ponies it’s certainly no slouch, but far from a modern heavyweight hitter. That is, until now. 
The Texas tuning wizards at Hennessey Performance have waved their hands across the Yukon Denali and dispensed tunes of 550 hp, 600 hp, and 650 hp.

 But for those who really need a super SUV, they’ve turned the big Yukon Denali into an 800 horsepower monster. Dropping the kids off at soccer never looked so fun.


Unlike some of the more conventional Hennessey modifications, which usually include a supercharger setup or twin-turbochargers, the firm’s HPE800 package entirely swaps out the Yukon’s stock motor in favor of a big 6.8-liter stroker version.

 Along with it comes a laundry list of racy upgrades including its balanced and blueprinted short block, aggressive crank and camshaft, aluminum pistons, billet steel connecting rods, ported cylinder heads, and lightweight intake valves with heavy-duty springs.
Even that isn’t enough on its own though. Hennessey also equips the behemoth V8 with a 2.9-liter supercharger, a burly intercooler, plus a new stainless steel mid-pipe exhaust and a high-flow catalytic converter.

The firm does say there’s an estimated drivetrain loss of about 15 to 20 percent once the big GMC Yukon puts its power to the ground, but even so the engine sure has a lot to give—a massive 805 hp at 6,000 rpm and 827 lb.-ft. of torque at 3,800 rpm.


According to Hennessey, that’s enough to deliver a zero to 60 mph dash in a jaw-dropping 4.1 seconds, and if you keep your foot hard to the floor, the SUV will blitz the quarter mile in 12.2 seconds. For comparison’s sake, the Challenger Hellcat runs the quarter mile in 11.2 ticks of the clock on street tires.

Thinking of challenging one of these at your local drag strip? Perhaps a rethink is in order.