June 22, 2024

Out post-es

Automotive rocks

2020 Cadillac CT6 4.2-liter Twin-Turbo Platinum; Tested At Last

Cadillac CT6 Full Overview

This should’ve been it. The American luxury/performance flagship sedan to finally stand up to V-8-powered German sedans like the Mercedes-AMG E 63 and S 63, BMW M5, M6 Gran Coupe, and 750i, and Audi RS 7 and S8 cars (and maybe even the Lexus GS F) that have dominated the continent-crossing swift-sedan market forever. But before we even got a chance to properly test a 2020 Cadillac CT6 4.2-liter twin-turbo Platinum powered by the mighty Blackwing V-8 introduced in 2018—let alone compare it against its competitors—the car was cancelled. Production ended in January.

Powertrain Fitness

It’s a crying shame, really (and probably a fire-able offense for the decision makers involved) to have designed and developed this high-tech engine from scratch, only to sell fewer than 1,400 examples before yanking the plug. Like the 4.0-liter twin-turbo V-8s from Audi and Mercedes and the 4.4-liter from BMW, it features two twin-scroll turbos mounted in the valley of the vee, cylinder deactivation of four cylinders, variable valve timing, direct injection, and a host of other high-tech features. It’s even hand-assembled and signed by its builder as many of the Euro engines are. Displacing 4.2 liters, the Blackwing’s ratings of 500-550 hp and 574-640 lb-ft (in Platinum or CT6-V trim) compare reasonably well to the sedan fitments of the competitor engines in Audis (453-591 hp and 487-590 lb-ft), BMWs (523-617 hp and 516-590 lb-ft), and Mercedes-AMGs (469-603 hp and 479-664 lb-ft). Furthermore, GM’s new ten-speed automatic meets or exceeds the performance of the eight- and nine-speed boxes currently serving the Germans in terms of shift smoothness and quickness, and shift-schedule logic, especially in sport modes.

Lean, Toned Body

At least as important as adding power is reducing weight, and the CT6’s Omega-platform chassis, derived from the Alpha platform that has been so well received in other Cadillacs and the Camaro, weighs in at just 4,407 pounds in its fully loaded Platinum trim (the sportier CT6-V likely weighs less). That’s 185 to 698 pounds less than any recent A8L, BMW 750i, or Mercedes-AMG S 63 we’ve measured. Comparing against the slightly smaller V-8 competitors it more closely matches in price, our CT6 Blackwing weighs 174 pounds less than our last E 63 S 4Matic and is about 140 pounds heavier than the BMW M5s we’ve weighed. Fitted with magnetic ride-control shocks and a sophisticated multi link front and rear suspension, the CT6 seems well equipped to battle these worthy competitors.

So How Does The CT6 4.2L Twin-Turbo Perform?

The 60-mph mark flashes by in 4.1 seconds en route to a 12.4-second 113.0-mph quarter mile. That handily quashes the BMW 750i (4.3 and 12.7 seconds) and entry non-V-8 Audi and Mercedes flagships, but the Audi RS 7 and the Mercedes-AMG S 63 handily smoke the Cadillac (3.3/11.5 and 3.4/11.6 seconds, respectively), as do the smaller E 63, M5/M6, and even the BMW M550i xDrive. The CT6-V would doubtless shave a few tenths off that performance, but it probably won’t vanquish the industry stalwarts.

The story’s pretty much the same on cornering, where the CT6 posted a reasonable 0.91g average lateral grip—better than 750i/A8L (0.90/0.89 g) while falling short of the grip displayed by the zootier full- and midsize sport sedans. That’s not bad performance, given the Cadillac’s more ride-oriented Goodyear Eagle Touring tires, which only managed a 119-foot stop from 60 mph—that’s 3 to 22 feet longer than any of the considered competitors. Available Eagle F1 Asymmetric 3 summer tires on the CT6-V would no doubt improve notably on both of these results. (Our figure-eight course was not available due to the global pandemic.)

What’s The CT6 Blackwing Like to Drive?

Cadillac strikes a nice balance in this CT6 between providing reasonable driving dynamics when your adrenaline is running, and relaxed touring behavior when it’s not. Body motion control is composed, steering feel is good for the class, and the brake pedal feels better than its lackluster stopping distances suggest. The 10-speed Hydra-Matic transmission is superbly paired with this engine and programmed so well as to obviate the need for shift paddles. Could this 4.2TT or possibly a well-driven CT6-V outrun an S 63, Alpina B7, or S8 on a French corniche in a Ronin-style bad-guys chase? Possibly not, but presuming you don’t die in the chase, you’ll revel in the soothing Bose Panaray tunes and find it much easier to wind down while driving the CT6 4.2L Platinum home afterwards with the Super Cruise set (presuming someone maps the French Autoroutes).

What’s It Like to Live With This CT6 Platinum?

Although its interior design, materials choices, and trim patterns aren’t as fabulous as those of the new Escalade, the CT6 cabin remains uniquely American and as distinctly Cadillac as the swaggering angular exterior. All that weight savings alluded to above costs the Cadillac somewhat in terms of noise isolation. It’s just not quite as quiet in here as it is in an A8, 7 Series, or S-Class. But what the CT6 lacks in library ambiance, it somewhat makes up for in library roominess, boasting more front and rear head- and legroom than the outgoing S-Class (Mercedes boasts way more shoulder room, however) and more overall front-seat passenger space than any of the considered competition; the Audi and BMW rear seats are bigger. At 15.8 cubic feet, there’s less trunk space than in the big Benz and BMW; more than in the Audi.

How Might a Blackwing CT6 Have Fared in a Comparison Test?

This totally depends on the contenders. Matched against Audi, BMW, and Mercedes press-car flagships that match the CT6 4.2TT AWD reasonably closely on price would have precluded V-8 engines in the competitors, giving the Cadillac a big performance advantage. This, coupled with its savvy packaging, light weight, and high feature content (especially Super Cruise) might have been enough to land Cadillac a win. Had we paired it with smaller high-performance contenders that still come close in price, we’d have had to step down to an optioned-up E or possibly C 63 AMG from Mercedes, a base M5 (still a few thousand more), and settled for an Audi S6 with a twin-turbo V-6 or spent more for the V-8-powered RS 6 wagon. Any of those pairings would really call for the CT6-V, which might have seemed richer in space, comfort, and features at some expense of performance. That might portend a mid-pack finish. Sadly, no such comparisons are likely to happen.

What Next for Blackwing?

Prior to the cancelled Geneva Motor Show, Manifattura Automobili Torino, an Italian coachbuilder known for producing the New Stratos (styled to resemble Lancia’s legendary rally car) and boutique builder of cars like the forthcoming Aspark Owl electric hypercar, reportedly struck a handshake deal with GM to supply Blackwing engines for an unspecified future product. But shortly thereafter GM sold its Turin engine center and publicly announced that this deal was off. That seems tragic. Why deprive the world of this excellent engine? And wouldn’t the bean counters be pleased to recoup a bit more of the engine’s lofty development costs selling engines at a price befitting a handmade Italian exotic?

Looks good! More details?

2020 Cadillac CT6 4.2TT AWD
BASE PRICE $98,790
VEHICLE LAYOUT Front-engine, AWD, 5-pass, 4-door sedan
ENGINE 4.2L/500-hp/574-lb-ft twin-turbo DOHC 32-valve V-8
TRANSMISSION 10-speed automatic
CURB WEIGHT (F/R DIST) 4,407 lb (55/45%)
WHEELBASE 122.4 in
LENGTH x WIDTH x HEIGHT 205.8 x 74.0 x 58.0 in
0-60 MPH 4.1 sec
QUARTER MILE 12.4 sec @ 113.0 mph
BRAKING, 60-0 MPH 119 ft
ENERGY CONS, CITY/HWY 241/135 kW-hrs/100 miles
CO2 EMISSIONS, COMB 1.11 lb/mile