Under the hood, the Hyundai Elantra is powered by an all-new 1.8-liter Nu four-cylinder engine with 148 horsepower and 131 lb-ft of torque (145 horsepower and 130 lb-ft of torque for Elantra PZEV). The Nu engine was developed to replace the 2.0-liter Beta engine from the previous generation Hyundai Elantra. The Nu is smaller in size, weighs 74 pounds less and helps achieve an 18-percent improvement in highway fuel economy, when compared with its predecessor. Thanks to advanced clean engine technology, most Hyundai Elantras sold in California, Oregon and several Northeast states are certified as Partial Zero Emission Vehicles (PZEV) by the EPA. The PZEV Elantra is as clean as many hybrid electric vehicles. The PZEV Elantra helps Hyundai meet its environmental commitments. Outside of these "green" states, the Hyundai Elantra is available as an Ultra Low Emission Vehicle (ULEV). Aluminum block and head Dual Continuously Variable Valve Timing (D-CVVT) Variable Induction System (VIS) Roller swing arm and Hydraulic Lash Adjusters (HLA) Electronic throttle control Offset crankshaft

The Nu engine features an aluminum block with a cast iron cylinder liner, cylinder head and crank. This unique configuration results in a block that is 30 percent lighter than an iron block, shedding more than 74 pounds off the entire engine weight, while still providing comparable strength.

The 1.8-liter Nu also offers Dual Continuously Variable Valve Timing (D-CVVT) camshafts and hydraulic engine mounts for optimum power, efficiency and refinement. Using D-CVVT on both camshafts has several advantages when compared with using it just on the intake camshaft. They include a two percent improvement in performance (increased volumetric efficiency), two percent improvement in fuel economy (reduced pumping loss) and a 30 percent reduction in hydrocarbon emissions. In the valvetrain, roller swing arms and hydraulic lash adjusters reduce valve driven friction to improve fuel economy one percent compared with direct valve driving. The Nu engine also features a maintenance-free silent timing chain system to enhance durability and improve Noise Vibration and Harshness (NVH).

The application of a plastic two-stage Variable Intake System (VIS), enables switching between long and short intake manifolds, resulting in an across-the-board performance increase. These result in a four percent improvement in performance, a 15 percent reduction in cost and 30 percent reduction in weight, when compared with aluminum.

Another tool Hyundai engineers have incorporated into the next generation Hyundai Elantra is an electronic throttle control. The electronic throttle control replaces the conventional cable and mechanical linkage found in the previous generation Hyundai Elantra with fast responding electronics. This system accurately controls air intake and engine torque, improving drivability, response and fuel economy.

Hyundai's first application of double-pipe plumbing (internal heat exchanger) is found in Hyundai Elantra. Double-pipe plumbing improves cabin cooling performance, while minimizing the capacity of the compressor, which further reduces fuel consumption. An external controlled variable compressor is also used to improve fuel efficiency versus an internal variable compressor.

The Nu four-cylinder engine also has an offset crankshaft design that reduces friction between the piston and cylinder wall for a one percent improvement in fuel economy.