From Motor1 · Brian Potter · · 1m
2027 GMC Sierra V8 Power vs Efficiency
The 2027 GMC Sierra's V8 engine delivers more power but less fuel efficiency than the Duramax diesel.
In brief
The 2027 GMC Sierra's V8 engine delivers more power but less fuel efficiency than the Duramax diesel. The 2027 GMC Sierra's V8 engines produce more power but lower combined fuel economy than the Duramax diesel across all trim levels. Originally reported by Motor1.
2027 GMC Sierra V8 Engine Ratings
The 2027 GMC Sierra's V8 engines post lower combined fuel economy than the Duramax diesel across all trim levels.
2027 V8 Fuel Economy Figures
Two-wheel-drive 5.7-liter V8: 15 mpg city, 19 mpg highway, 17 mpg combined. Four-wheel-drive 5.7-liter V8: 16 mpg city, 20 mpg highway, 18 mpg combined.
2027 Duramax Diesel Ratings
Two-wheel-drive Duramax: 23 mpg city, 28 mpg highway, 25 mpg combined. Four-wheel-drive Duramax: 22 mpg city, 26 mpg highway, 24 mpg combined.
V8 vs Outgoing Engines
The new 5.7-liter V8 replaces the 5.3-liter with more power but lower mileage. The 6.6-liter V8 replaces the 6.2-liter with more power but lower mileage.
The headline
The 2027 GMC Sierra's V8 engines produce more power but lower combined fuel economy than the Duramax diesel across all trim levels.
