“We’re none too pleased to have you here.”
Soul-crushing words from Corvette chief engineer Tadge Juechter. Chevy’s PR department, relenting to MotorTrend‘s barrage of begging for early C8 Corvette access, has twisted Juechter’s arm into letting me ride shotgun for three rotations of a development drive in the latest C8 prototypes (uncamouflaged production-spec 2020 Corvettes are shown here).
His team is loath to expose the press to anything less than a fully baked, buffed, and polished, production-ready, no-excuses Corvette—and this drive is a crucial step in that baking/buffing/polishing process. Upon solemnly swearing not to report on any buzzes, squeaks, rattles, vibrations, mismatched trim pieces, or other quality lapses I may detect, I strap into the right seat of a 2020 Chevrolet Corvette Stingray Z51 with FE4 suspension.
Interested in the 2020 Chevrolet Corvette? See our comprehensive coverage HERE.
“Cars are complicated,” Juechter deadpans from the driver’s seat, noting that writing, developing, and perfecting the software that controls the myriad microchips, solenoids, motors, features, and functions on a modern car takes vastly longer than any other aspect of bringing a car to market.
The process starts at vehicle inception, and final calibration tweaks are made right up to and sometimes past launch. On today’s drive, Juechter’s team is scrutinizing powertrain calibrations—especially concerning launch feel and the ability of the clutches in the Tremec eight-speed twin-clutch transmission to mask the 6.2-liter V-8’s transitions in and out of four-cylinder mode at various cruising speeds.
Developing a suitable transaxle has been a limiting factor to the whole concept of a mid-engine Corvette since the 1960s, when transaxles from the front-drive Olds Toronado and the rear-drive Pontiac Tempest (among others) proved inadequate. My ride, precisely six weeks in advance of the press launch, reveals a pretty impressive state of tune.
Shifts in automatic mode sound and feel incredibly swift and smooth, and I’m unable to detect any four-cylinder mode vibrations. Juechter notes that the very first prototype transaxles performed almost perfectly at 70 percent or greater throttle. The challenge has been tuning for every other condition. Later on, vehicle performance manager Alex MacDonald will call my attention to an abrupt transmission engagement issue he’s tagged for follow-up. I hadn’t noticed it. These cars are nearly ready for prime time.
But back to this FE4 Z51 with magnetorheological dampers. We are traversing scabrous pavement and railroad crossings in Tour mode, and the ride quality delivered by the car’s run-flat 35-series 19-inch front and 30-series 20-inch rear tires is impressively plush. Juechter then rests his wrist on the Lexus-like pad above the rotary drive- and weather-mode controller switch and dials up Sport and Track modes, each of which noticeably ratchet up the road feel. I ask why the system doesn’t just deliver the smoothest ride possible until you brake or steer, and his answer is, “Folks want the knob to ‘do’ something.”
I am pleased to hear that the car will “remember” either Tour or Sport mode after cycling the ignition, which required EPA certification to be done in both modes with results being averaged for CAFE and window-sticker reporting.
We ride along, discussing the many challenges presented by transitioning the Corvette from front-mid to mid-rear engine positioning. (There were no in-house experts to consult, no similar GM cars to build mules from, and lots of unknown unknowns.)
I’m struck by how conversational the cockpit is. The engine note is textbook small-block background music, which comes to the foreground a bit when an exhaust valve in the muffler opens in Sport or Track mode. Most of what I’m hearing is organic, but the active noise-cancellation sound system does a tiny bit of frequency augmentation, as well—primarily of exhaust sound, because the pipes are now muffled by a luggage area and the engine. They’re also positioned way behind our ears, and sound pressure drops with the square of distance.
Getting the chassis balance right with a 40/60 weight balance was another big challenge. Mid-rear-engine cars have a natural tendency toward midcorner understeer, but tuning the springs and bars to neutralize that part of the corner can mess up the car’s entry and exit behavior. So the team optimized the electronic limited-slip differential tuning to make the car more neutral midcorner while tuning the bars and springs for entry and exit. (That multiplate-clutch type e-LSD works like the old one, except it’s now powered by the transaxle pump.)
During my stint with lead development engineer Mike Petrucci in an FE3 Z51 Stingray, our route affords a few opportunities for hard acceleration out of some corners, which the new chassis dispatches without a hint of wheelspin. I’m pinned to the seat with no oversteer. Clearly it’s going to take a lot more concentration to drift this generation of Stingray than it has most previous gens. (Future Z06s and ZR1s might be a different story.) This car’s ride feels enough stiffer than the MR car’s Sport setting that if I were buying a car for Michigan roads, I’d prioritize the FE4 suspension over any other options when speccing out a Z51.
Petrucci takes me through the Stingray Z51’s aerodynamic upgrades, which include a subtle chin spoiler balanced by a hybrid spoiler/wing in back that works like the one that’s about to make its debut on the Shelby GT500. An aggressive duckbill spoiler in the center generates big downforce from the air coming down off the rear hatch window, and the outer wing sections develop some additional downforce while allowing most of the air coming around the cockpit to flow under with reduced drag.
The body sculpting also optimizes cooling airflow through the side-mounted radiators, and a smooth underbelly pan further reduces drag. The rear diffuser generates little or no downforce because the muffler lives right where a venturi tunnel would need to be in order to generate downforce. Petrucci claims that at speed the Z51’s aero package produces measurable downforce, not just reduced lift.
Asked what competitors his team benchmarked, Petrucci mentions the usual suspects—Porsche Cayman, Ferrari 458 and 488, McLaren 570, and Ford GT—but he notes that owners of these cars don’t typically expect them to be as well rounded and everyday-usable as a Corvette. His baby therefore needs to be easier to get into and out of (modest sills and conventional doors help), less punishing, and capable of hauling weekend luggage. I’m promised that the one regulation roll-aboard suitcase and two modest golf bags that fit in today’s C7 hatch will fit in the C8, but split between front and rear trunks. I wasn’t allowed to inspect either trunk to verify this assertion, however, but we know total trunk space adds to 12.6 cubic feet—down from the C7’s 15.0 cubic feet.
All too soon my three 20-minute sessions are over, and I’m left watching the three camoed Corvettes roar back toward their home base at GM’s Milford Proving Ground, my appetite well and truly whetted for my first chance at the left front seat.
Source: Read Full Article