The 310-hp "Turbo Plus" version of the Chevy Colorado lineup's shared 2.7-liter turbo four-cylinder engine is included, as well, but with the lower 391-lb-ft torque output instead of the ZR2's 430-lb-ft figure. The Trail Boss is also the least expensive Colorado with low-range gearing; those lesser trucks' 4x4 setups only have high-range 4WD settings. Every four-wheel-drive Colorado gets an "auto" setting for the high range, though; it engages 4WD automatically when the system detects wheel slip.