( http://www.TFLcar.com ) The 2012 Jeep Grand Cherokee SRT8 is the fastest and most powerful vehicle that Jeep has ever built. With a massive HEMI engine that produces 470 HP and 465 lb-ft of torque. At Sea Level it will easily accelerate from 0-60 MPH in under 5 seconds. But when we tested the car at about one mile above sea level in Denver we got a 0-60 MPH time of 6.1 seconds. To find out why there's such a significant difference between the two times we put the new Jeep Grand Cherokee SRT8 on a Dyno and did a Dyno test to determine the real horsepower at all for wheels. Check out this video to find out why car are so much slower at high altitudes than at sea level.