Jamie Standring, SRT's senior manager for powertrain engineering, told CarAdvice there’s a lot more going on under the surface of the 2018 Jeep Grand Cherokee Trackhawk than merely generating bulk power and torque from the supercharged V8 engine.
“Certainly packaging was one of the challenges,” Standring said. “The driveline, in particular, was a challenge because of the 30mm longer transmission.”
You’d think a large SUV like the Grand Cherokee would have more than enough physical space to add a toughened driveline, but, of course, it isn't quite so simple.
Driving the production car, as we’ve now done at launch, is an interesting experience in sampling the finished product without understanding all the nuances that had to be taken care of in development. Shoehorning a supercharged V8 into an AWD platform wasn’t a complete nightmare for SRT engineers, but it presented unique challenges.
“The other difficult issues are things you can’t specifically analyse [quite] as well,” Standring told CarAdvice. “Transmission case oil temperatures under load, for example. There are no analytical tools that allow you to monitor a fluid-solid interaction.”
In short, Standring means that engineers couldn’t measure what would happen until they tested the driveline under prolonged loads.
“That becomes a development challenge,” Standring said. “You can't predict it, you run into it headlong during testing and then you have to work it out. In other words, we have to develop our way out of the problem.”
I wondered whether the cooling needs of such a powerful engine would be a challenge during hot weather testing, but the solution, as you’d expect, came from pretty close to home.
“The cooling system in this vehicle, much of it we took from the Dodge Hellcat, and everything was sized appropriately to the engine,” Standring explained. “We basically looked at the entire system, and the brief was to fit it all in the front end of the Jeep.”
Standring went on to explain that the cooling system, therefore, was comparatively easy to negotiate - given the hardware was already proven in another platform.
“It was more about opening enough real estate on the front end to get as much air in as we needed,” he said. “We don’t need foglights, for example, and we gave them up for better airflow. For a higher purpose, so to speak. And the higher purpose in SRT and Powertrain is power.”
The obvious question for endlessly unsatisfied petrolheads, is whether there’s wriggle room for a Demon variant of the Grand Cherokee Trackhawk, with even more power and torque.
“It would be challenging to make more power than this,” Standring said. “It would be very challenging. We’re pretty much at the limit for half-shaft tolerance, for example, at this point. To do more, we'd have to tear up the rear end of the vehicle.”
It’s not as simple as just adding more power, either. Harnessing it is key. “You’d have to package a bigger axle, bigger half shafts, which is very difficult in this architecture, the suspension architecture in particular is an issue,” Standring said. “Who needs more anyway?”
Well, too much power is never enough, and surely one of you madmen in the SRT skunkworks have thought about it?
“No comment,”Standring says with a laugh.
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