No reason was provided, but we can make a pretty educated guess. All TX models, whether 350 or 500h, use Toyota’s new 2.4-liter turbocharged four-cylinder engine that produces 275 horsepower and 317 lb-ft of torque. The 500h adds a parallel hybrid system, pushing the output to 366 hp and 409 lb-ft.
The TX 550+ has a more complex powertrain setup, with the basis being the well-known 3.5-liter naturally aspirated V6. It’s equipped with two electric motors and an 18.1 kWh battery pack good for a claimed electric-only range of 33 miles. The PHEV produces 406 hp, which is good for a sub-five-second sprint to 60 mph, though that figure hardly matters in three-row family crossovers.
One explanation is less reliance on the 3.5 V6 engine. Toyota Motor Manufacturing Alabama builds V6 engines for the Highlander, Tacoma, and the previous-generation Lexus RX 350. All of these models have now moved on to the turbocharged four-pot.
