Tim Roman is a mechanical engineer by trade and an all-wheel-drive fanatic by choice. Years ago, he modified a Merkur Xr4Ti to spin all four tires—and later installed a turbocharged Ford V8. He was soon hooked, and now he's finishing up a more ambitious project: making an AWD 2017 Mustang. Naturally, he chose a Coyote V8-powered GT model.
This was no easy task, and Roman has been at it for a long time. We're finally seeing the final results. After documenting the entire process on his modest YouTube channel, No Production Value Garage his Mustang is now on the ground and sending power to every corner. The parts to make this happen came from all over the automotive world, and the custom fabrication involved doesn't interfere with the car's daily drivability or outward appearance at all. "The whole point of the car is to make it act like an OEM made it," Roman says. "Completely daily-drivable, smooth, AC, not [crazy]."
Roman bought the Mustang in the fall of 2019 and spent the first few years of ownership poking around the vehicle's drivetrain and researching whether his idea was even achievable. There has obviously never been a production all-wheel-drive Mustang, so making one may not have even been possible. If the space wasn't there for all the extra parts—or more room couldn't be made—then the whole project would've fallen flat on its face. That, thankfully, is not what happened.
The AWD setup Roman came up with is mechanically very similar to something you would find in other longitudinal-engined sedans. There's a conventional transmission with a transfer case on the back of it that sends power up to a differential mounted next to the oil pan. One axle travels through a tunnel in the pan while the other goes straight to the spindle. This is how it's done on vehicles like xDrive-equipped BMW 3 Series.
Gallery: AWD Ford S550 Mustang GT
The mix of parts to get the job done is a laundry list of components from several automakers. The transmission is a six-speed manual TR6060, which is a staple of many performance cars. The front differential is from a 1986-1995 Toyota Hilux. The transfer case is a variable torque-split Borg Warner unit, commonly equipped on older AWD Dodge Chargers.
Almost everything in between those components, including many portions of those otherwise stock parts, is custom. A lot of stuff had to be moved around to make space for the new machinery as well. The steering rack, for instance, had to be relocated, and the oil pan, spindles, and other components were likewise heavily modified or made from scratch. Importantly, though, the interior of the car has barely been altered at all—just a small bump in the transmission tunnel on the passenger's side. The outside is also unchanged. You would never know it was all-wheel-drive unless someone told you.
Roman's build series on YouTube covers all of the nitty gritty details, but in short, the project was never held up by any unsolvable mechanical crises, only juggling the project with a day job and a family. As such, it's taken months longer than Roman expected to get the project going. Check out the almost final results, though:
I say almost final because, like any project, it's never really done. Roman says he wants to replace the motor mounts to improve the car's daily-drivability, as well as making final versions of things like the axles, which are currently shortened versions of stock axles off of other cars.
There's also a bigger problem; the car no longer has enough power to make any tire smoke. Since all four 295-section tires are now spinning in anger, the car cannot break traction on a dry surface. Roman has been planning to buy a supercharger kit or install twin turbos for some time, but it's important for him to actually enjoy using the AWD Mustang for a little while before it's back up on the lift. "I wanna drive it all summer [and] I wanna bring it to car shows," he says. "I'll sacrifice everything to basically not have it on the lift all summer again." That means the boost will have to wait until the cold weather returns, as much fun driving it in the snow is.
After all this, you may be wondering: How much weight does adding AWD to a sixth-gen Mustang add? Well, Roman insists improvements to the car's mass could be made by switching to aluminum differential and transmission housings, but the stock GT Mustang now only weighs 3,911 pounds versus its original weight of around 3,750 pounds. Once he installs new two-piece brake rotors, that figure will drop below 3,900 pounds. In other words, there's a minor weight penalty to pay for the added capability. The car can also still be operated as a RWD 'Stang thanks to a new transfer case controller, so it can switch right back to factory feeling with the touch of a button.
It goes without saying that Roman's project is incredibly impressive. He wants to enable other people to make the same mods to their cars, but it's not that simple. He could share the plans for the necessary custom parts, sure, but the output shaft of the TR6060 has to be resplined, among other non-trivial changes. So while the end result is extremely cool, it's not exactly something he thinks can be easily replicated.
We will get to enjoy AWD burnouts just as soon as Roman gets around to finding the right form of forced induction, though. We may not be able to build our own AWD S550, but at least Roman's is going to rip.