Last month we have reported the existence of the Jeep Grand Cherokee SRT Hellcat with the supercharged 6.2L HEMI V8.
Recently, some other automobile medias claim that, they have heard from their “source” that the upcoming Grand Cherokee SRT Hellcat is able to reach a top speed of 200mph and run the 0-60 mph within 3 seconds (for example, this report).
While we cannot confirm whether the Grand Cherokee SRT Hellcat can reach 60mph in less than 3 seconds, we can definitely see in order to reach the speed of 200mph, how many horsepower the HEMI V8 engine need to make.
Using the same calculation procedure in our previous article (which calculates the output requirement for the Volkswagen Phaeton), with the Grand Cherokee SRT’s parameters shown below:
Drag coefficient – 0.39
Cross sectional area – 3.18 square meter
Real curb weight + one driver: 2,500 kg (this is only for the naturally aspirated SRT, definitely underestimated, since the SRT Hellcat also includes the supercharger components)
To let the Grand Cherokee SRT Hellcat maintain a speed of 200mph (322 km/h) it need at least 6,408+368 = 6,776 N at wheel, which translates to 606 kW (812 hp).
The above calculation shows: if the Grand Cherokee SRT Hellcat needs to run at the speed of 200mph, it must have around 800hp at its wheels. Since there will be parasitic loss in the drivetrain (especially for the Grand Cherokee’s AWD setup, usually at least 15% loss percentage), the engine output must be much greater than 800hp (should be around 950hp at least) to maintain the 200mph speed.
Considering the current supercharged V8 on the Dodge Challenger/Charger can only supply 707hp, therefore unless Jeep significantly upgraded the engine to let it make at least 250hp more, there is no way that the SUV can reach 200mph.
While the above information may disappoint some Jeep fans, the calculation is based on facts and science. At the same time, I highly doubt the proficiency/credibility of the above mentioned “source”: even a junior automotive engineer will have the basic instinct of how many horsepower it takes to let this big SUV reach the speed of 200mph.