After “The Fast and the Furious” sparked a series of questionable exploits in his Ford Taurus SHO, NASA Arizona’s Chris Mayfield was forced to make a meaningful decision: lose his license or find a safer setting to find his fix. He chose the latter.
Working in a series of machine shops made Mayfield a capable mechanic and unknowingly served him well as he moved through various autocross classes and into Time Trial in a succession of quick BMWs. One of which, an E36 M3 built by its previous owner for German Touring Series 2, was the right foundation for moving into the top rung of TT, and so Mayfield made all the necessary changes to make it right at home in TT3. He was set on a conventional path back then, and the chassis had enough ceiling to give him the range of experiences he was then after.
Over a couple years, regularly running in all the Rocky Mountain Region events honed his craft, and in 2013, Mayfield attended his first NASA Championships event at what was then Miller Motorsports Park and won it by .3 seconds against Ken Smith in his C5 Corvette.
At the start of 2014, Mayfield and Ryan Neff started chats around an aero business they had been pondering. Neff, an IMSA engineer, and his brother Tyler had started an engineering design business with a focus on aerodynamics development. Both graduates of the Formula SAE program, the Neff brothers took what they’d learned to begin Zebulon Motorsports Consulting, then focusing on elements for formula and sports cars.
Neff and Mayfield went back a ways, so they decided to collaborate on one of Zebulon’s first splitters for a GT application. This profiled front splitter replaced the flat carbon blade that had been there before, and the difference it made was drastic. As Mayfield was trying to learn the nuances of Sonoma Raceway during the Western States Championships in 2014, he had to contend with a car that was pointier than anything he’d experienced before.
“I spent that entire first session countersteering,” Mayfield laughed.
“He never realized what the effect would be. He went from two degrees of wing angle to laying it forward like a barn door,” said Neff.
These challenges would be a lot on anyone’s plate, but Mayfield had done his homework and felt confident. Because he’d been running his car lighter and less powerful than some of the other cars in the midst that weekend, he figured he’d likely be in the window, provided he could find the last few tenths. “I guessed I’d be a second off the pace,” he said.
His boldness would be tested when he witnessed a big-bore Trans Am built for TTU gridded in front and began showing Mayfield the lines. When the Trans Am went off at Turn 10 and rolled in a big way, Mayfield realized what the consequences were for getting it wrong at this daunting track.
Spooked, he had to work himself back up to speed. At the time he started feeling at ease in the cabin, the No. 3 BMW M3 ahead demonstrated the proper entry procedure for Turn 10: do not brake.
Mimicking the man in front, Mayfield found the half-second he was searching for. “I lifted, clenched my sphincter, and tried not to drop a wheel,” he recalled.
That simple approach yielded the lap time that took the TT3 win.
He’d clinched two NASA Championships on a shoestring, but his good fortune couldn’t last forever. When the S54 blew at the start of 2015, Mayfield had to hang up his helmet for two years until a new line of work and a generous friend helped him back into the seat.
So he moved to San Francisco and took a new role with Tesla. Concurrently, he started making cross-country treks to various One Lap Of America events with a friend in an E92 M3, and suddenly his stars had aligned. With the paycheck and the positive emotion needed to return to TT3, he decided to start again — but he’d need a new car — and, as it turned out, a new apartment.
Working for such a large company has its perks, and Mayfield acted on one. He took the opportunity to relocate to Phoenix, where Tesla’s test facilities were within easy driving distance and the cost of living was considerably less. Just after moving in, a friend back in San Francisco notified Mayfield of a Lotus Evora with fixable damage for sale, so he sighed and bought a plane ticket back to the city he had just left. For the price the owner was asking, Mayfield had to inspect this unloved Lotus.
This half-off deal hinged on a broken gearbox, general neglect, and an unwanted tenant. A vagrant had made the place his personal campsite for weeks, but even with the smell and the litter, the price was right, and Mayfield’s new house had a two-post lift he could use to repair the thing. Maybe he could flip this Lotus and double his money.
Leaving San Francisco helped demonstrate just what kind of presence a midengine sports car actually has in an anti-car city. “It didn’t garner the negative attention some exotics do,” he admitted.
The drive back wasn’t the schlep he thought it might be. Fourth and fifth gears were toast, but the spread of torque across the supercharged Toyota 3.5-liter V6’s rev range was broad enough to cruise comfortably in sixth along Interstate 10. The interior, though not exactly opulent, felt special. It was a pleasant place to be, and he was pleasantly surprised at how versatile his new purchase really was, which forced him to reconsider. Though Mayfield might have been certain about selling the car before he started the trek, after arriving in Arizona fresh and wholly satisfied with its road manners, he wasn’t so sure anymore. It made him smile, kept him comfortable, and saved him some money. A nickname was in order, and “Penny” was the one picked.
He still had his misgivings, though. All but the most minor of engine work requires removal of the engine and transmission, so off came the rear clamshell, then the powertrain, and in went a new transmission with an MFactory helical differential bolted to it. This was daunting, since information was scarce. However, the generous folks on the Lotustalk forums helped Mayfield make quick work of the drivetrain repairs.
The upside was he didn’t have to do much else. Unlike the front-engine BMWs he had gotten familiar with, the Lotus needed far less modification for track work. With AP Racing four-pot calipers, Ferodo FS2500 pads, a ducted radiator, twin oil coolers, a flat underbody, a decent-size diffuser, double wishbones straight from the factory, there wasn’t much else for Mayfield to do but eyeball an alignment. Like that, he headed west to Buttonwillow one sweltering afternoon for an eye-opening shakedown.
Its sturdiness was on full display that day. The temps remained stable throughout — a testament to the non-intercooled engine’s OEM cooling system.
Best of all, its grand tourer considerations made its performance accessible. Its gentle breakaway and the feel of its hydraulic steering made it easy to dance with. Its lift-off rotation was controllable enough — more so than an Elise’s might be. “It’s prone to oversteer from late braking at corner entry.”
On corner exit, the differential helped generate real propulsion, even with one tire partially lit. However, the rapid diff lockup would cause a little understeer right at tip-in, even though no weight had been transferred. This rapid alternation between oversteer and understeer was more useful in Buttonwillow’s short corners than its long ones, where it was harder to commit confidently.
Because of its balance and habit of over-rotation at corner entry, it didn’t need as much negative camber at the front as his Bimmers did. “I was blown away — even on stock suspension, it was well balanced and approachable.”
All that performance wrapped up in a package with soft edges helped Mayfield set a 1:58 on his second flyer.
By this stage, he gave up on flipping the car for profit — he had seen so much already, and he had only scratched the surface. He was able to diagnose the car’s few shortcomings and turned to the clever Fred Zust at Black Watch Racing for a few items to bring the most out of this stellar chassis. Along with a set of custom upper control arms for increased negative camber, Fred sourced a set of custom Penske 7500 two-ways.
No Butchery Required
When Mayfield returned to Arizona, Neff just so happened to be in town 3-D scanning another customer’s car. Mayfield proposed they link up to scan his new purchase to build some aero for this unsupported car.
Even though the Evora is built more like a sports car, Neff adhered to his M.O. for GT cars and the like: that the front gets precedence. Generally speaking, a car with this weight needs a great deal more aerodynamic loading at the front axle to get the desired balance.
Neff devised a 6-inch splitter, which provides the ideal combination of downforce and efficiency. This item protrudes from the front of the bumper and extends all the way to the front axle line, where it blends seamlessly into the factory flat floor. This element features tunnels and a profiled design, too.
To maintain some ground clearance, Chris had to move the factory oil coolers upward 2 inches, and trim the bottom of the factory bumper — so much for resale value. Fabricating the splitter mounts also took some creativity, but in the end the splitter was mounted at just six points, all completely hidden behind the bumper. Strong enough to allow someone to stand anywhere on the front of the splitter, the mounts also were designed to allow the splitter to deflect upward in case of a big compression or curb strike.
Because the rear clamshell isn’t rated to support serious aero loading, Neff had to get creative designing a set of mounts that only require a pair of holes drilled into the rain tray. These connect to a support that bolts directly to the chassis, and two elegant swan necks that pass through the panel gaps between the rear clam and the fenders. It took several passes to get around the hatch cleanly, but, fortunately, this is a British car, so its fender gaps are wider than some.
“The big aero problem with the Evora is that it’s a body-on-frame car, and the clams are monocoques of their own. This layout limits the amount of space for airflow through and around the car,” Neff elaborated.
The finishing touches on the first iteration of the aero package were: a set of skirt extensions that widen the surface area of the floor, and bolted on a set of his “angle cutters,” which manage the inflow of air underneath the car. “The cutters function like a virtual sliding skirt, helping seal the underbody and maximize downforce,” he added.
To top off this first round of modifications, Mayfield stuffed as much tire as he could fit under the factory bodywork — from a set of 235s and 275s, front and rear, respectively to 265s and 315s. The car was already on the cusp of TT2 with the forced-induction modifier, so he decided to pick a set of Super 200TWs and try for another few TT3 titles.
With the new parts in place, Mayfield went back to High Plains Raceway east of Denver, and spent an unbearably hot afternoon inside the Evora, and not only for its air conditioning. In the sharpened car, he immediately set a lap 4 seconds faster than his first visit when the car was stock. Incredibly, the minimum speeds were significantly higher in the Lotus than the existing TT3 record lap that Mayfield also holds. These initial laps were less than 2 seconds off that record, and conditions were far from ideal.
At Podium Club Atessa several weeks later, he found himself trading new TT3 records with Cameron Lane in his LS-swapped RX-8, a major name in the Southwest. Both were running the 200 TW modifiers. Less than a month with the new aero and Mayfield was already setting records.
More Important Than Money
On his return to Buttonwillow, he logged a 1:51 the first session. The second session, he bled off the throttle in the middle of Riverside and saw his smoke fill his mirrors. “I set a white smokescreen as I lifted prior to turning into Riverside. I’d seen little puffs before, but never this much.”
The motor picked back up several seconds later, but as he trudged into the pits, it went into limp mode.
The 2GR V6’s crankcase ventilation simply isn’t rated for 1.5 g’s of lateral acceleration, and the pooling of oil in the head was dumped into the intake manifold under lifting, choking the engine and damaging a piston ring land.
Fortunately for the mechanically inclined Mayfield, this wasn’t a damper on his spirits. The Toyota 2GR V6 is plentiful and cheap, and the opportunity to work on a motor removed from its cramped confines gave him the chance to explore his headroom in the TT3 points scheme. Replacing the stamped steel headers and integrated cats for a pair of catless aftermarket stainless-steel headers brought numbers up to 356 peak horsepower and 342 average horsepower. Torque is roughly 300 pound-feet at the rear wheels, and the spread allows Mayfield to shift infrequently.
Back at High Plains with the new engine, he ran laps more than a second faster than the TT3 record. The new motor in place helped some, but the notable improvements over his previous best were in the high-speed corners.
He’s considered limiting the peak power to bring his average power number down so he can reduce weight. “Currently, I’m barely making minimum weight (3,070 pounds) with my tank three-quarters full. Remembering to refuel regularly is a nuisance.”
Peering Over the Horizon
Having a strong foundation to build upon raises the ceiling. Widening the window between grip and slip is the first matter of business. The rapid rotation at corner entry is fine for shorter, more technical tracks, but the helical differential’s snappy alteration from understeer to oversteer simply by playing with the throttle has made it tough to find the ideal line through faster corners. The proposed 1.5-way OS Giken clutch-type diff should lock and unlock more progressively.
It might offer several traction-related advantages, too, which will come in handy if he goes ahead and builds the motor. A turbocharged, intercooled engine might make as much as 550 horsepower, which would slot the Evora nicely into TT1. “I could probably take another hundred pounds out of it pretty easily, too.”
“I’m thrilled with the car because it’s been fun and unique. I’d recommend it to someone who wants to enjoy an analog car on track. Even in stock form, it’s very competent and pretty versatile.”
Rapid development has been possible through his day job and the skills it strengthens, the right racing connections, and a certain boldness — exploring a largely unproven sports car with a premium price tag is not for the meek. Wading through uncharted waters is easier with friends on forums and a few skilled friends to help address the shortcomings in the car’s aftermarket support, but it has been adventurous, and fairly stress-free, fortunately.
The front bumper looks sandblasted, but it’s still an eye-catcher. So much for making a quick buck. Penny is a keeper.
