Car and Driver did some real world testing and found out that the four-cylinder Silverado got WORSE MPG than its optional V8 engine. But how?

One of the main reasons anyone would shell out more money for a smaller turbocharged engine in a truck or performance car is that, over the long-term, you’ll perhaps save a bit more money on fuel. But, what if it turns out that the fuel saver four-cylinder actually gets WORSE MPG than engines with more displacement. Now, what’s the purpose of a smaller engine? Car and Driver ran two Silverados, one with a 2.7L turbocharged four-cylinder under the hood and the other with a 5.3L naturally aspirated V8, both were paired to an eight-speed automatic with the same transfer cases on its 75 MPH highway fuel economy run. The results are shocking. The V8 used less fuel than the turbo four. But, how?

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First, let’s go over the tail of the tape.

  • The 2.7L turbo puts out an astonishing 310 HP and 348 lb-ft and the EPA says its capable of 20 MPG combined.
  • On the other hand, the 5.3L V8 puts out 355 HP and 383 lb-ft with an 18 MPG combined.

The turbo SHOULD get better MPG on C&D’s test loop, right? Not so! On the 75 MPH test the turbo got 18 MPG while the V8 got 21 MPG.

I’m not going to pretend that I know the nuances of EPA testing for MPG or what exactly was the difference between the two so bear with me.

The 2.7L turbo is a DYNO QUEEN, pure and simple. In order for GM to come out with sensational headlines like

The all-new 2019 Chevrolet Silverado 1500 with the technologically advanced 2.7L Turbo offers full-size truck customers a capable and efficient choice with an EPA-estimated fuel economy of 20 mpg city/23 mpg highway in rear-wheel-drive models.

They specifically prepared their engines to ace the EPA standardized tests. The EPA is not keeping its testing procedures a secret. As a matter of fact, they are common knowledge. The EPA runs test vehicles through a series of drive cycles meant to replicate city, highway and other scenarios of driving. If you take a look at their highway drive cycle, average MPH hovers around 50 MPH. Even when you take their high-speed drive cycle into consideration, average MPH stays the same but there are sections where they do run test vehicles up to 80 MPH for an extended period of time. No one really runs their cars with an average speed of 50 MPH on any highway. In California, you’d be relegated to the slow lane if police don’t pull you over first for impeding the flow of traffic.

Car and Driver’s test stays around 75 MPH where the 2.7L turbos are spinning, sucking in more air needed to maintain enough pulling power to keep this three-ton truck hurtling down the road at speed. The V8, on the other hand, uses all 8-cylinders to get the Silverado up to speed and then shuts off a bank of cylinders, sipping fuel, more efficient at highway speeds than the four-cylinder.

Under ideal conditions, the 2.7L turbo is pretty fuel efficient as long as you stay out of boost and treat the throttle like there’s an egg under the pedal. But, if you’re looking for usable power that’s more forgiving under real-world conditions, the V8 Silverado is the engine you want.

Source: Car and Driver

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