The GS 450h continues as a series-parallel hybrid, which means it’s capable of operating in electric-only, gas-only, or a combination of the two modes. Its 286-horsepower 3.5-liter gasoline V6 now uses the Atkinson cycle for greater fuel efficiency.
The result? An estimated 29 city, 34 highway and 31 combined mpg, a colossal improvement over the previous GS hybrid’s numbers (22 city/25 highway/23 combined mpg). Even more impressive is the fact that Lexus claims that the new 2013 Lexus GS 450h will hit 60 mph in 5.6 seconds and carry on to a top speed of 131 mph. It may be more efficient, but it’s certainly not any slower.
This is an improved GS hybrid for sure, if not in pure drivability then in terms of interior quality, design and definitely handling due to the standard-issue adaptive suspension. Lexus isn’t expecting the GS 450h to set the world on fire with sales numbers. It’s guessing that the GS 450h will account for less than 10 percent of the total GS mix.
The jump from the previous model’s 23 mpg average to a 31 mpg average with the new model is astounding, especially when the power penalty is just two horsepower (from 340 hp to 338 hp) — this really changes the character of the GS and makes for a compelling reason for GS 350 owners to upgrade to the hybrid, especially now that the GS 450h will be available in a Standard & Luxury package.