At the heart of the new RX models beat two improved V6 powertrains.

The range-topping RX 450h features an enhanced version of the company's Lexus Hybrid Drive system with a 3.5-liter V6 gasoline engine that crank out a combined output of 295HP, 27 more horsepower than the current generation RX hybrid. Lexus also added two new systems that improve the RX450h's efficiency. The first is an exhaust-heat recovery system that reduces engine warm-up time allowing it to stop earlier, more often, and for longer periods while the second is a cooled exhaust-gas recirculation system that reduces engine pumping losses, also helping to improve economy.

The entry-level 2010 RX 350 is powered by the same powerplant as the RX450h, sans the hybrid system. In this case, the 3.5-liter V6 engine produces an output of 275HP and is mated to an electrically controlled, sequential-shift six-speed transmission.

Source: Carscoop