Factory Fresh

Full­size Four-Cylin­der

Truckin - - TABLE OF CONTENTS -

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 V-6 en­gines. Ford is best known for this phe­nom­e­non, mak­ing waves in 2011 when it made the EcoBoost 3.5L twin­tur­bocharged V-6 its top en­gine op­tion, and then again in 2015 with a sur­pris­ingly small 2.7L EcoBoost V-6.

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 ’19 Sil­ver­ado LT and RST. This small en­gine will pro­duce 310 hp at 5,600 rpm and 348 lb-ft of torque 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, as well as the 4.3L V-6 that cur­rently serves as the Sil­ver­ado 1500’s en­try-level mill. In the ’18 Sil­ver­ado, the EcoTec V-6 makes

285 hp at 5,300 rpm, with 305 lb-ft mak­ing an ap­pear­ance at 3,900 rpm. Ford’s nat­u­rally as­pi­rated 3.3L V-6 makes 290 hp and 265 lb-ft, while Ram’s Pen­tas­tar 3.6L V-6 has 305 hp and 269 lb-ft.

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 1 and 4.

Fur­ther­more, the 2.7L 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.

Chevro­let in­tro­duced us to the 2.7L turbo af­ter al­low­ing us to drive a cur­rent-gen­er­a­tion ’18 truck with the 5.3L V-8 dur­ing 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, power de­liv­ery was so in­stan­ta­neous that we were sur­prised to learn there wasn’t an elec­tric mo­tor adding a lit­tle ex­tra torque. We were keenly sur­prised that the en­gine’s mo­ti­va­tion was solely through a sin­gle turbo, as any lag was nearly im­per­cep­ti­ble.

Fur­ther­more, driv­ing the ’18 and ’19 Sil­ver­ado 1500 back to back showed just how much the new truck has im­proved over its pre­de­ces­sor. Im­pact harsh­ness while ma­neu­ver­ing 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 ’19 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 model. 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 ½-ton pickup, we’d have laughed in their face (or at least po­litely sup­pressed a guf­faw). But our brief time proved a tur­bocharged 2.7L I-4 can in­deed pull around the ’19 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.

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