Pre-Production Drive: 2019 Chevrolet Silverado 1500 2.7L Turbo I-4Posted in News on May 17, 2018
Engine downsizing has been the subject of much discussion over the past decade or so, with truck automakers abandoning large-displacement V-8s in favor of efficient, powerful-enough V-6 engines. Ford is perhaps best-known for this phenomenon, making waves in 2011 when it made the EcoBoost 3.5L twin-turbocharged V-6 its top engine option and then again in 2015 with a surprisingly small 2.7L EcoBoost V-6, serving as a middle child between the base 3.5L naturally aspirated V-6 and the more conventional 5.0L V-8.
But now, Chevrolet will likely dominate the small-engine conversation with its latest announcement: a turbocharged 2.7L I-4 that will be offered as the base engine for the 2019 Silverado 1500 LT and RST. The 2.7L I-4, which was revealed yesterday at GM’s Milford Proving Ground, will produce 310 hp at 5,600 rpm and 348 lb-ft from 1,500 to 4,000 rpm on regular fuel, with the snail producing up to 22 psi of boost.
Those numbers compare well to the competition’s base engines. Ford’s naturally aspirated 3.3L V-6, which replaced the 3.5L V-6 in the 2018 F-150, produces 290 hp and 265 lb-ft. The 2019 Ram 1500 and its 3.6L Pentastar V-6 get an eTorque mild-hybrid system, good for 305 hp and 269 lb-ft (with eTorque adding 90 lb-ft from a standstill). Like the Ram V-6, Chevy’s 2.7L turbo four is mated to an eight-speed automatic transmission, while Ford’s base engine gets by with a six-speed auto.
Chevrolet claims the 2.7L I-4 was developed as a truck engine from the start, with key goals being efficient performance, a high specific mass to power output, and leading low-speed torque and turbocharger response. In order to achieve these goals, engine designers incorporated a variety of technologies, including a tri-mode valvetrain: high valve lift for maximum power, low valve lift for low-demand cruising, and a no-lift profile that shuts down the second and third cylinders for improved fuel efficiency. This system, which is the first application of Chevy’s Active Fuel Management on a four-cylinder engine, retains the low-lift valve profile for cylinders One and Four.
Furthermore, the 2.7 also includes a dual-volute, twin-scroll turbocharger to nearly eliminate lag. Twin-scroll technology separates the exhaust manifold into one section for the second and third cylinders and another section for the first and fourth. This helps ensure the turbo keeps spinning through two distinct exhaust pulses. However, unlike other twin-scroll turbos, the 2.7L engine’s snail also includes dual-volute technology, which keeps both exhaust pulses separate until they reach the turbine at two locations opposite one another. This helps the turbo respond almost immediately to each and every twitch of the loud pedal. Electronic boost control and an electrically actuated wastegate further help improve operating efficiency.
Chevrolet introduced us to the 2.7L Turbo after allowing us to drive a current-generation 2018 truck with the 5.3L V-8 over a ride-and-handling course at the Milford Proving Ground. After familiarizing ourselves once again with the outgoing Silverado, we were given the keys to its replacement and told only that we were piloting a gasoline, non–V-8 engine. Immediately upon setting out, it was obvious we were driving something turbocharged, but only because we could hear a faint whistle emanating from the front end. Throttle response was excellent, with each press of the gas pedal resulting in a commensurate increase in speed. In fact, turbo lag was so nonexistent that we wondered if the truck was also hybridized, with a small electric motor providing instant torque while the turbo spooled up. After vocally theorizing such, the Chevrolet employee who was riding along informed us we were half-right (turbocharged), keen to maintain secrecy until a presentation later in the day that would illuminate powertrain specifics. We were surprised that the engine’s motivation was solely through a single turbo, as any lag was nearly imperceptible.
Furthermore, driving the 2018 and 2019 Silverado 1500 back to back showed just how much the new truck has improved over its predecessor. Impact harshness over GM’s deliberately harsh proving ground pavement is reduced, and the ride is much smoother. Driving through curves with midcorner washboard, wheel control is much improved with less skittering on the front wheels. And interior quietness, long a hallmark of GM’s fullsize trucks, is as good or better than the previous machine.
Of course, we have a few gripes that persist from when we saw the debut of the 2019 Silverado 1500 at the 2018 North American International Auto Show. Interior styling is already dated, with the instrument panel and center stack looking too much like they do in the outgoing truck. And while almost everyone likes the truck’s wider, squarer stance, its modern exterior design is still polarizing—for the record, this writer loves it, particularly in RST and Trail Boss trims.
We’re also eyeing the turbocharged 2.7L I-4 with some skepticism, as Ford’s similarly sized EcoBoost V-6 drives well unloaded but can sometimes feel a bit winded when saddled with a trailer or a full bed. The 2.7L Turbo’s payload, towing capacity, and fuel economy numbers are still to come, but the engine’s Assistant Chief Engineer Craig Marriot says we won’t be disappointed with the compact engine’s performance in the real world. And our experience with the truck on a closed course cast no aspersions as to the truck’s usability as a daily driver, family hauler, and weekend errand machine.
Ten years ago, if someone told us a four-cylinder engine could haul around a well-equipped 1/2-ton pickup, we’d have laughed in their face (or at least politely suppressed a guffaw). But our brief time proved that a turbocharged 2.7L I-4 can indeed pull around the 2019 Silverado 1500 not just adequately, but eagerly. We can’t wait to put Chevrolet’s new I-4 through its paces in other situations, but our first impression of the engine is very, very good.