Never before has there been such a varied range of powertrains for performance cars. Decades ago, if you wanted a car that was fun to drive, you opted for something with a rear-wheel-drive chassis that was mated to the largest-displacement engine with the highest number of cylinders that the manufacturer could fit in the engine bay. Things have changed. Massive naturally aspirated engines no longer reign supreme, as automakers have downsized their engine offerings to improve fuel efficiency and emissions. The mantra “There’s no replacement for displacement” has been replaced; now the preference is for forced-induction, small-displacement turbocharged and supercharged engines. At the same time, engines have started to be paired with high-tech hybrid systems in the performance arena, not solely to improve fuel efficiency but to add speed with a less severe efficiency penalty than in the past.
Lexus is in a somewhat unique position and is bucking that trend. When it comes to powertrain technology in three top Lexus performance models, the operative words are natural aspiration, displacement, and sophistication. Whether it’s feature-laden 32-valve V-8 engines mated to their latest up-to-10-speed automatic transmissions, or advanced multistage hybrid powertrains, Lexus is able to deliver performance in different ways.
The V-8 used in the 2017 Lexus RC F and GS F benefits from years of evolution—three decades, in fact. Take a look at today’s 2UR-GSE, and you’ll see similarities between it and the 1UZ-FE engine designed for the original Lexus LS400 that launched in 1989. Since that time, bore spacing has been constant on every Lexus V-8. Many other internal aspects such as block deck height remain unchanged. It all testifies to the soundness of the original design. Yet, with application of new technology and engine management systems, the specific output of 62.5 horsepower per liter from the original 1UZ-FE V-8 in the LS400 has risen to today’s 93.4 horsepower per liter in the RC F and GS F. And that’s without forced induction—just a 7300-rpm redline and the wail from the intake and exhaust systems.
The RC F and GS F share a front-engine/rear-wheel-drive layout and similar drivetrains. The action starts with the all-aluminum DOHC 5.0-liter (4969 cc) V-8, which has a 90-degree angle between cylinder banks for an even firing order and the inherent balance it provides. With a bore and stroke of 3.70 x 3.52 inches (94.0 x 89.5 mm), it’s slightly oversquare. The compression ratio of 12.3:1 is much higher than the 10.0:1 of the original 1UZ-FE V-8.
The DOHC heads are populated with 32 titanium valves, and both the intake and exhaust valve timing are adjustable, although the two are controlled differently. The intake valve timing is electric (Lexus calls it electric variable valve timing, or VVT-iE), while the exhaust timing is hydraulic (variable valve timing, or VVT-i). The lowercase i in each shorthand stands for “intelligence.” A further distinction with this Lexus V-8 is that it can vary its intake-valve timing to the extent that it can operate in both a traditional Otto cycle, for high-demand moments, and a highly efficient Atkinson cycle, where the closing of intake valves is delayed to effectively increase the expansion ratio to improve efficiency during relaxed cruising. Lexus’s years of variable-valve-timing experience have fostered the development of a system that effectively operates as “two engines in one.” The transitions between the two are quick and seamless.
Fueling is by high-pressure D-4S direct injection with secondary port injectors. The D-4S designation for “Direct Four Stroke” pairs high-pressure in-cylinder injectors with lower-pressure port injectors that automatically deploy as driving conditions demand, helping to ensure both high power output and reduced fuel consumption and emissions.
Taken as a whole, the 2UR-GSE V-8 produces 467 horsepower at 7100 rpm and 389 lb-ft of torque at 4800 rpm in both the RC F and the GS F. Redline is at 7300 rpm. Lexus V-8s have always been noted for internal smoothness and immediate throttle response. The current engine offers all that, of course, but it also gives the cars some tomcat attitude as well, issuing a baritone note through the tuned intake manifold and the stacked tailpipes.
In either car, the engine mates with the AA80E eight-speed Sport Direct Shift automatic transmission. The driver can select Manual mode for full control with paddle shifters, and in this mode the torque converter is fully locked in second gear and above for a responsive feel that approximates that of a manual transmission. Gear ratios are closely spaced from second through sixth, with seventh and eight being overdrive ratios. Lexus G-force Artificial Intelligence Shift Control (G AI-SHIFT) monitors all dynamics and, in Sport S and Sport S+ driving modes, sharpens responses while also overseeing rev matching on downshifts.
Both cars offer strong performance. The RC F dashes from zero to 60 mph in 4.4 seconds, runs a 12.5-second quarter mile, and tops out at 170 mph. EPA estimates are 16 city/25 highway/19 combined mpg.
The GS F is just a hair behind: zero to 60 mph in 4.5 seconds, 12.8 seconds in the quarter, and a 168-mph top speed. Fuel economy is the same except for the highway rating, which is 24 mpg.
You would think a company would call it a day after creating two V-8 beasts that still qualify as low-emission vehicles. But no. Lexus decided to push its hybrid technology to the limit by adapting it to its all-new grand touring coupe, the LC500h.
Lexus hybrids have been noted for their gasoline engines that operate exclusively on the Atkinson cycle. The LC500h continues the tradition with the 8GR-FXS engine, a 24-valve DOHC 3.5-liter (3456 cc) V-6 with D-4S injection. Bore and stroke are 3.70 x 3.27 inches (94.0 x 83.0 mm), and the compression ratio is 13.0:1. Lightweight valvetrain components and reciprocating parts, reduced friction, and high-flow intake ports let the engine achieve a 6600-rpm redline.
The V-6 teams with two water-cooled, permanent-magnet synchronous high-output electric motor-generators that mount in the transmission case to assist the gasoline engine. They’re integrated with Lexus’s first application of lithium-ion batteries, a more compact power source compared with the nickel-metal hydride cells previously employed in Lexus hybrids. With 84 cells supplying 310.8 volts, the lithium pack snugs between the coupe’s rear seat and its luggage compartment.
The multistage hybrid transmission is as innovative as the rest of the drivetrain, and a first for Lexus. As is typical with Lexus hybrids, the LC500h has a compact planetary gearset to blend the power from the engine and electric motors in a continuously variable arrangement. What’s new this time around is that there’s also a conventional four-speed automatic appended to the end of the CVT part of the transmission. These additional ratios allow for electric-only driving at higher speeds, allow the electric motors to provide more thrust at elevated speeds, and improve efficiency overall.
Because of what Lexus spokesman Paul Williamsen called “good, steady improvement in packaging density,” the total length of the transmission unit is “only changed by about an inch or so” as compared with the nonhybrid LC500. The driver can engage M mode and use the paddle shifters to select one of the 10 simulated ratios manually.
Total system output is 354 horsepower. Yes, that’s less than the F performance vehicles, but the instant torque of the high-output electric motors helps the LC500h become the first Lexus hybrid that can spin its rear wheels from a stop. It dashes from zero to 60 mph in a very respectable claimed 4.7 seconds and achieves an electronically limited 155 mph. It can do all of that and return an EPA-estimated 26 city/35 highway/30 combined miles per gallon. This performance-oriented hybrid system in the LC500h is a step in the direction taken by the latest hypercars and prototype racers.
So, how would you like your performance? Lexus now has options to satisfy a variety of tastes.