Hood scoops look cool, but sometimes that’s all they do. Carmakers are often tempted to slap a non-functional hood scoop onto a new model, hoping consumers will envision performance capabilities the engine underneath doesn’t really have. However, the scoop on the 2017 Chevrolet Silverado HD is the real deal.

In addition to making Chevy’s big truck look like a muscle car, the scoop should provide some real-world benefits. It’s part of a new air-intake system meant to keep the Duramax diesel engine running at full power more often. Like humans, internal-combustion vehicles need to breathe, and the new system helps keep the Silverado HD from getting winded.

Most of the air is drawn into the engine through the scoop, meaning it’s closer to ambient temperatures and thus much cooler than air circulating under the hood. Engines run more efficiently off cool air, so this is a plus. The scoop also takes advantage of a ram-air effect, in which the speed of the truck actually forces more air into the engine. There’s also a secondary intake in one of the front fenders, in case the hood is blocked.

Read more: GM takes a step toward hybrid trucks with 2016 Chevy Silverado and GMC Sierra eAssist

Engines like air that is dry as well as cool. To minimize moisture, the intake system also has an air/water separator that forces air through a 180-degree turn before it gets sucked into the engine. Any moisture consolidates into large droplets, which are flung against the wall of the housing by centrifugal force, and then drained away.

No truck launch or update is complete without a description of a hardcore testing regimen, and Chevy certainly put the 2017 Silverado HD through its paces. Engineers simulated every type of precipitation possible, from what Chevy calls “monsoon-level downpours,” to snow, to ice pellets. It also tested trucks in a range of temperatures to see if they could pull heavy loads in extreme cold and heat.

It’s all about helping the Silverado HD’s Duramax diesel engine breathe easier. That engine is a 6.6-liter turbocharged V8 that produces 397 horsepower and 765 pound-feet of torque, and is coupled to a six-speed Allison automatic transmission. Expect the Silverado’s GMC Sierra HD twin to get the hood-scoop upgrade for the 2017 model year as well.