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perksofwifi · 5 years ago

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6 Tech Highlights From the 2020 Cadillac CT4

Cadillac’s smallest new sedan runs large on innovation, with a fancy new type of turbo, umpteen gillion customizable drive modes, a new double-jointed/hard-mounted front suspension, and more. Read on for all the 2020 Cadillac CT4 tech highlights.

Dual Volute Turbocharger

You’ve heard of twin-scroll turbos, so how does this new dual-volute setup differ? Both types segregate the exhaust stream from different pairs of cylinders such that cylinders that fire back-to-back don’t share a scroll (or volute). For example, in a four-cylinder, the first cylinder to fire is paired with the third and the second with the fourth. This ensures that the momentary vacuum created during valve overlap (when the intake opens before the exhaust valve closes) doesn’t mix with��and detract from—the pressure wave created by the next cylinder to fire. In a twin-scroll, these separate passages are next to one another inside the turbocharger’s “snail” housing, and they tend to combine at the point where both passages hit the turbine, where one exhaust stream can leak into the other. This is where the dual-volute setup differs. Here two larger passages are positioned atop one another, with each only reaching half-way around the turbine so each passage hits the turbine 180 degrees apart from the other. The larger passages flow more exhaust with less opportunity for mixing of the pulses, which improves throttle response across the rev range.

Modes Galore

Perhaps borrowing a page from BMW M, the latest Cadillac V offers considerable customization. Naturally the center-console mode selector switch permits tailoring of the exhaust sound, engine/transmission responsiveness, steering effort, and brake effort (rear-drive CT4-Vs would also add magnetic ride-control adjustment). To the standard Tour, Sport, and Track modes is added a “My Mode” that forces a Tour powertrain setting, but allows the driver to tailor engine sound (Stealth, Tour, Sport, Track), steering (Tour, Sport, Track), and brake response (Tour, Sport). There is also a V button on the steering wheel that allows the driver to instantly summon yet another custom assignment of the above options plus a powertrain option (Normal, Sport, Track, and Snow/Ice). My ideal setup: lightest effort (Tour) steering, Track powertrain, Sport brake response, Stealth exhaust, (and on a rear-driver, tour/max comfort for the suspension, because #michiganroads).

Double-Jointed

A new front strut suspension setup replaces a lower control arm with two lower links, each of which gets its own ball joint at the steering knuckle. The lateral one controls handling inputs via a more rigid inner mounting bushing that eliminates “slop” when cornering forces build up. The other is a diagonal link that controls ride. This link mounts to the suspension cradle via a larger front bushing, which allows longitudinal motion that can better absorb impacts from potholes or bumps. New thermoplastic urethane (TPU) jounce bumpers also afford a bit more suspension travel, further enhancing ride quality, while rigidly mounting the front powertrain/suspension cradle and steering rack improve handling precision and feel.

Tandem Starter

Don’t you hate when you just stop at a light and it turns green while the engine’s shutting down? In order to smooth these “change of mind” events, the CT4-V’s starter anticipates a stop/start event and synchronizes its gear with the flywheel, so that there’s no hesitation or harshness on a restart.

Stealth Lighting

Years ago Saab introduced a “Night Panel” button that extinguished virtually every lamp in the interior, leaving only the speedometer illuminated. Cadillac’s Stealth Lighting mode is engaged by dimming the dash lights all the way down. The PRNDL on the gearshift remains illuminated, as does the entire gauge cluster (and strangely enough, the indicators for park-distance and lane-keeping). The infotainment screen and all climate-control LEDs, along with ambient lighting all go dark.

ContiSeal or Run-Flat

Cadillac is introducing Continental’s new ProContact RX with ContiSeal technology on base CT4s—a claimed segment exclusive. Basically a gooey material inside the tire creates an airtight seal around any nail or screw that might penetrate the tread. V models get a choice of run-flat tires, including the Continental SportContact 6 SSRs summer tires on our test car or ProContact RX SSR all-season tires.

The post 6 Tech Highlights From the 2020 Cadillac CT4 appeared first on MotorTrend.

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