It's been a while since full-size trucks have used engines as small as 2.7 liters, but that's exactly what the 2015 Ford F-150 will use when you tick the Ecoboost box in the dealership.

It's not just 2.7 liters, of course--you also get six cylinders and two turbochargers, and it's those that Ford says gives it capability and performance to match the V-8 variants.

The company has released more technical details of the next-gen F-150's latest engine, and the figures are quite impressive.

Slotting below a new 3.5-liter V-6, Ford has paired its latest 2.7 with twin turbochargers for 325-horsepower and 375 lb-ft outputs.

That puts it a few horsepower shy of the 5.0-liter V-8 used in the 2014 F-150, but just 5 pounds-feet short of the V-8's maximum torque output.

MORE: Why Green Car Reports Writes About Full-Size Pickup Trucks

The main benefit of this is performance, particularly when it comes to towing, but given the 2015 F-150's aluminum construction and the 2.7's compact size, the power-to-weight ratio has improved significantly--it's 15 percent better over this metric than the 5.0 V-8.

In 4x2 format the 2015 F-150 2.7 Ecoboost has a payload of 2,250 lbs and a tow rating of 8,500 lbs--the latter actually 200 lbs more than the 2014 F-150's V-8 in 4x2 specification.

The smaller engine is beneficial for other reasons too, of course--namely fuel efficiency.

Uniquely for this class of vehicle, the engine features stop-start technology--shutting down the engine when stationary to avoid consuming fuel when it isn't needed. The engine re-starts as the driver lifts their foot off the brake--and is disabled completely when towing or in four-wheel drive mode.

MORE: 2015 Ford F-150 Gas Mileage: What We Know So Far

Ford is still remaining quiet on fuel consumption, but all F-150s are expected to jump in this regard thanks to the light-weight body, and the 2.7 should be best of the bunch.

Alongside the new unit, Ford has tweaked its old 3.7 liter V-6, resulting in a new 3.5-liter version. With 283 horsepower and 255 lb-ft of torque, it's out-punched by the Ecoboost and indeed its predecessor--but again, power-to-weight improves by 5 percent.

Maximum payload is 1,910 pounds, and towing capacity is rated at 7,600 pounds.

Whether the 3.5, or Ford's new 2.7, are capable of beating the diesel-powered RAM 1500 EcoDiesel is another matter--but its 28 mpg highway rating is a target to aim for.


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