By Phil Royle — Aug. 26, 2022

(Editor’s note: This article originally appeared in the July/Aug. 2022 issue of SportsCar magazine, the official member magazine of the Sports Car Club of America. You can also listen to an interview we did with AEM’s Lawson Mollica on episode 54 of The Watt Car podcast.)

I wasn’t piloting the only EV at that weekend’s SCCA Cal Club Region autocross – far from it. I was, however, in the only EV conversion. The black Mustang I peered over the steering wheel of began life as a 2007 powered by a V-8. The pistons, however, had been swapped for parts from a Tesla, a minivan, and electronics from AEM. The bodywork was stock, making the Mustang as unassuming in appearance as it was silent in its motion. Yet even without a sound, this vehicle drew a crowd.

AEM’s Marketing and PR Director Lawson Mollica had jumped at the opportunity to bring AEM’s EV-converted Mustang to an SCCA Autocross for me to try – a vehicle the AEM folks dubbed their “Testang” due to the Tesla motor powering the rear wheels.

Before me in the driver’s seat sat multiple buttons on AEM’s CAN Keypad, one of which instantaneously dialed in the power – one push for about 300N-m of torque, another for 350N-m, then 400N-m, and a maximum of 450N-m – roughly 220lb-ft of torque up to 330lb-ft. My plan was to start with the lowest setting, upping the dial for each autocross runs.

As the starter waved the green flag at the line, I eased into the throttle to experience silence. Well, the tires were making noise. Still, I didn’t miss the roar of exhaust; instead, I was left fathoming how I could get all of this torque to the ground. You see, while a 4.6L motor may produce 320lb-ft, it does so above 4,000rpm. Electric motors hit hard from near zero.

Back in the grid after my first run, Lawson inquired, “You want to step up the power?” My answer was as instant as the torque: “I think I’ll keep it here for a while,” I laughed.
I dialed the power up later, but it was more a smoke show than anything. The torque is an unrelenting kick in the back. There’s no ramp. But if your right foot is patient, an electric setup is a beast.

The weight balance of AEM’s Tesla-powered Mustang proved better than the original ICE counterpart.

What Lies Beneath
Much like he did on site with the flood of questions from other competitors, Lawson ran me through the Testang’s specs. “When you pop the hood, gone is the three-valve, 4.6L Mod motor and the transmission, driveline – everything’s gone,” Lawson explains. “Now sitting up front are six battery packs from a hybrid. They are stacked three across, two high in the engine compartment. And adjacent to that is a DC-to-DC inverter.”

With the internal combustion motor gone, a solution is needed for the accessories. “We sourced an electric power steering pump, for our cooling loop we utilize a Tesla pump, and then we’ve got essentially an electronic brake booster,” Lawson says. Under the hood there are also some big switches for cutting power to the system, and from AEM’s shelves, there’s an AEM Power Distribution Unit, VCU200, and Battery Management System.

Under the hood of the Mustang sits hybrid batteries from a minivan along with a whole slew of electronics, including AEM’s PDU, VCU200, BMS, and more.

“Teslas are unitized very well; it’s on a subframe [and] it’s packaged brilliantly,” Lawson describes of the electric motor assembly that now resides on the AEM Mustang’s rear axle. “It’s got the inverter on one side and the motor on the other. It’s got the gearbox with the 9.7:1 reduction gear – basically a one speed – right in the middle, and it’s ripe for being put in whatever you want to put it in. And that’s what we did with the Testang.”

Tesla’s control board comes out, AEM’s goes in, and the VCU200 connects to the Tesla inverter. From there, torque mapping can be accomplished, which is how I was able to play with multiple power settings on the fly, controlled by AEM’s CAN Keypad and viewed via an AEM CD-5 data-logging dash.

“We [also] have the BMS [Battery Management System] 18, which stands for 18 [battery] cell tap,” says Lawson. “From that one, you connect satellites to it. We have the six [battery packs under the hood], so we have one master and six satellites, and each one of those satellites attaches to the master via serial that transmits all of the individual cell data to the Battery Management System over CAN bus.”

There are another six battery packs throughout the car, some in the transmission tunnel and others where the gas tank once resided, with all of the programming for the BMS done through the VCU.

“We took the same approach to the PDU, our Power Distribution Unit,” says Lawson. “It’s an eight-channel module and can be daisy chained. It’s really just a way to switch things on and off, which can [also] be programmed through the VCU.”

Beneath the Mustang’s trunk floor sits electronics prominently on display due to the fact that this Mustang is essentially a (super cool) marketing tool. The Tesla motor is also quite visible.

There’s more, but as Lawson adds, it’s simpler than it sounds. “It sounds complicated, but it’s really easy,” he says. “You have one place to program everything, and you have all the hardware devices you need to have OE control across your conversion. And that gives you the ability to enjoy the vehicle and get the most out of it.”

Lawson says the Testang might cost about $50,000 to replicate. “As EVs go, it’s a pretty affordable build and it’s plenty of fun,” he says. “I live a little over 30 miles from AEM and can commute in that car. I go up and back with a little bit of room to spare. And I can drag race the car – it does a best of 11.78 in the quarter mile at 117mph. And it’s not too bad on the autocross course.

“This is why [AEM] built the Testang. It’s a rolling example of what’s possible, what’s attainable with electric propulsion, and how much fun it can be.”

A Home Within SCCA Autocross
EV classing in SCCA Autocross has been taking place on the fly. As of late, performance-based EVs like the Tesla Model 3 Performance have been classed in Super Street. Most recently, though, an EV autocross class has been created to allow for EVs modified beyond the realm of the Street category.

“The initiative to create a specific class for EVs was in the works prior to the Tesla winning B Street [at the 2019 Tire Rack SCCA Solo National Championships],” members of the Solo Events Board told me. “While some [SCCA] members may have had interest in the EV-X concept after the Model 3 was moved to Super Street, the creation of the class centered more around showcasing the technology, and also gives owners who want to modify their cars a place to compete without potentially upsetting the current [balance in] Street Touring™ classes.”

The rear axle has been swapped to accommodate a Tesla setup.

EV-X, the new EV-exclusive class, isn’t eligible for a championship at the Solo National Championships, but EV-X drivers are welcome to the party. “EV-X…will be a supplemental class offered at the Solo Nationals,” states the SEB. “The SEB and SCCA National Office will continue to evaluate the popularity and member input going forward with regards to future expansion of potential EV classes.”

EVs are also welcome in ProSolo competition, especially with the recent addition of the EV Challenge at Tire Rack SCCA ProSolo Series events. Although there, “EV” doesn’t necessarily mean electric power only. “The EV Challenge, which stands for ‘Electrified Vehicles,’ is open to all EV and hybrid vehicles, and is a permanent addition to the ProSolo Challenges and will be run at the [ProSolo] Finale,” says the SEB. “With the rapidly expanding interest and market, it was an easy decision to add the EV Challenge.”

AEM’s CD-5 Data Logging Dash offers not only a speed display, but also voltage, state of charge, a breakdown of battery pack health, and more.

Where the Testang Fits
We entered AEM’s Testang in a catchall autocross class that the local SCCA Region offers, with the class allowing easy access to autocross for anyone with virtually any vehicle that can legally be driven on the road. Why didn’t we enter the Testang in the new EV-X class? Well, it’s because the new EV category class isn’t ready for EV conversions – yet.

“Currently, there are multiple EVs classed within the Street category which allows for very limited modifications. In addition, we have a modified EV class – EV-X – that is focused around suspension modifications, but retaining the stock drivetrain and programming,” the SCCA’s Solo Events Board (SEB) explains. Tinkerers rest easy, though, as there is research being put into where vehicles like AEM’s Testang will fit in the future. “The SCCA and National Board of Directors have created a committee called the EVAC [Electric Vehicle Advisory Committee] that is working on a set of safety rules that could apply to home-built EV vehicles due to potential safety risks that haven't been contemplated before.

AEM’s CAN Keypad controls the basic functions of the Mustang, with power output controllable on the fly.

“The culmination of that work on the EVAC could pave the way towards allowing EV-swapped drivetrains or creating home-built EV drivetrains for their highly modified cars. More to come on this as the risks are evaluated.”

Autocrossing AEM’s Tesgang, it’s obvious that a future of electric vehicles is quite exciting. In fact, this Mustang only weighed a few hundred pounds more than a stock Mustang GT, and my “butt” corner weighting scale indicated the EV’s balance was superior. Yes, there are bugs to be worked out as we head into an EV future, but even after one event, it was easy for me to see that the inclusion of EVs in SCCA competition is, shall we say, inEVitable.

(Images by Phil Royle)

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