BMW 550i vs. Lexus GS 450h

Road and Track, July 1st, 2006

Sports sedans represent almost everything that is good about automobiles. They possess the performance to satisfy weekend racers, yet still have the civility to double as family cars. They’re also status symbols (mainly because purchasing a proper one usually comes at a price north of $35,000). If there’s anything to fault about these wonderfully diverse pieces of machinery, it would be fuel economy: Big engines and heavy bodies often translate to high gasoline bills.

Not anymore. Enter Lexus with the world’s first hybrid sports sedan. You may be thinking, “Sure, a hybrid may get better fuel mileage, but it won’t have anywhere near the performance of a conventionally powered sports sedan.” Don’t be too quick to judge. The Lexus GS 450h’s specifications indicate that it performs as well, or even better, than its V-8-powered counterparts…and according to Lexus, achieves up to 33-percent better fuel economy. Too good to be true? That’s what we wanted to know, so we decided to put the Lexus up against one of the best-performing V-8 sports sedans in the marketplace today, the BMW 550i, and sampled them back to back on twisty mountain roads and in the cluttered streets of downtown San Diego. After the dust had cleared, Road Test Editor Shaun Bailey preferred the conventional gasoline-powered car, while International Editor Sam Mitani opted for the hybrid. Read on.

Lexus GS 450h

by Sam Mitani

Okay so I don’t hug trees or carry signs that read “Save the Cochabamba Mountain Finch,” but the unusually high rainfall here in Southern California recently, not to mention the numerous hurricanesand tornadoes across the country, is confirmation enough that the earth is changing, and not for the better. While most of us are willing to recycle and conserve, car enthusiasts aren’t quite yet ready to give up driving fast.

Thanks to Lexus, we may not have to.

The new GS 450h features the latest variation of Toyota’s revolutionary Hybrid Synergy Drive. But before you dismiss the new sedan as an oversized Toyota Prius, take a look at its performance numbers. The GS 450h is just about as quick as the mighty BMW 550i and a step better than many other V-8-powered sedans.

What makes the GS 450h so special is the all-new electric motor…actually, two of them. Both are of the permanent magnetic type: One acts as the primary generator, engine starter and controls engine speed, while the other sends power to the rear wheels. Mated to them is a brand-new CVT transmission that features a two-stage torque application device (Toyota calls it a torque multiplication device) that essentially gives the electric motors a taller gear for speeds above 60 mph. The transition from one stage to the other is so smooth that you won’t be able to notice it unless you pay close attention.

The gasoline-powered part of the equationis Toyota’s bulletproof 3.5-liter V-6. Even by itself, this powerplant—dubbed2GR-FSE—is impressive, featuring variable valve timing and both direct and port fuel injection. And when it’s combined with the electric motor, you have the makings of something very special.

Total output of the GS 450h is 339 bhp. The gasoline-powered engine supplies 292bhp at 6400 rpm and 267 lb.-ft. of torque at 4800, while the electric motors provide the rest. When you depress the throttle pedal at a standstill, the 4155-lb. sedan leaps off the line, as bucket-loads of torque are instantly transferred to the driving surface. It gets to 60 mph in just 5.3 seconds, and does so in a very hushed manner. In fact, it’s so quiet,you lose your sense of speed unless you look down at the speedometer.

Where the Lexus takes a back seat to the Bimmer is in handling. The 550i’s agilityis extraordinary, while the 450h’s is just very good. On a long stretch of winding road, I just couldn’t keep pace with Bailey in the BMW, which negotiated the road’s numerous decreasing-radius corners as if it were second nature. The GS 450h, on the other hand, struggled, with good amounts of understeer through all the tight stuff. What was even more frustrating was the car’s traction-control system, which can’t be totally defeated; it has a tendency to zap power when it’s needed most. The GS’s steering lacked the sharpness of the BMW’s, exhibiting an overactive assist system that resulted in an artificial overall feel.

One odd trait I discovered was when flooring the throttle pedal in “Normal” mode, there’s a slight pause before the power is transferred to the rear wheels. It’s much less noticeable in “Power” mode, but it’s there nonetheless—we discovered it has something to do with Lexus’ super complicatedCVT (see sidebar). That said, don’t blame the hybrid system for the GS450h’s handling…it’s just that BMW’s chassis has been set up for performance driving, whereas the Lexus’ has been tuned more for comfort and highway cruising.

And on the highway, the Lexus shines. It is dead quiet at startup because the engine doesn’t come on until there’s a certain amount of load. Even when traveling at 80-plus mph, the cabin stays amazingly peaceful with little intrusion of wind and road noise. The GS 450h’s ride quality is velvety smooth, with the suspension system—upper and lower A-arms up frontand a multilink setup at the rear—doing an adequate job of soaking up potholes and dealing with debris and anything else bad weather leaves behind.

For the record, the GS 450h recorded fuel mileage of 18.7 mpg, which is lower than the EPA number. One should note that we drove the GS 450h much harder than the average luxury-sedan driver; a lighter right foot and extended exposure to stop-and-go traffic would significantly improve this number. What’s more, the new Lexus is designated as a SULEV (Super Ultra-Low Emissions Vehicle), and Toyota estimates that it has 80 percent less smog-forming emissions than the average new car.

And best of all, there’s no high premium for the Lexus sports sedan: It comes with a base price of $54,900, which undercuts the Bimmer by a few thousand dollars and makes us wonder why anyone would want to buy it or the $51,375 V-8-powered Lexus GS 430.

The GS 450h offers tremendous upside and virtually no downside. It allows you to be environmentally correct (whether you realize it or not) while still providing you with kicks on Route 66 or any other road that tickles your fancy. Perhaps the only negative thing about the new Lexus is that it may put V-8-powered sports sedans like the BMW 550i on the endangered species list.

BMW 550i by Shaun Bailey

Forget the fossil-fuel gluttony and old tech; the hybrid is new, modern and fuel efficient. At least that’s what Toyota would like us to think. They would like us to forget our expectations of performance and be happy with a Prius that sacrifices speed and agility for the benefit of our ecosystem. Great intentions, and we even applaud the gas-sippers for saving our planet and making the world a better place.

But we are hesitant to believe that the new Lexus GS 450h can meet its hype as a fuel-efficient sports sedan. It claims fuel efficiency of a V-6 and performance of a V-8. Maybe it’s fast in a straight line, but is it as sporting as BMW’s latest V-8-powered sedan, the 550i?

The latest iteration of BMW’s 5 Series V-8 is arguably as big a technical achievement as the hybrid drive system. It’s a 4.8-liter 4-cam, 4-valve-per-cylinder engine that features the coolest of throttles—no butterflies to obstruct airflow, or turbulence-inducing barrels, just smooth runners that flow air cleanly at all rpm. To control air induction, a system called Valvetronic varies lift of intake valves. Not just a 2-stage system that switches cam profiles like that in Honda’s VTEC, Valvetronic can vary the range completely from full open to full close as quickly as the gas pedal is pressed. This ingenious design improves breathing efficiency, throttle response, smoothness and power production. It helps the V-8 knock out 360 horsepower and 360 lb.-ft. of torque.

At full rip, the 550i managed to hit 60 mph 0.3 sec. quicker than the 450h and held that all the way through the quarter mile. Applause must be given to the Lexus, for it will probably catch an automatic equipped 550i (our test car was fitted with a 6-speed manual) in the same contest. The Hybrid Synergy Drive’s continuously variable transmission works well in acceleration by keeping the engine and electric motor working at optimal rpm. A manual transmission is less efficient, having to work up through an engine rpm range to accelerate. This is not as much of a weakness as one might think. It is a necessity for a sports sedan, because a sports car is meant to be driven sportingly.

Performance-car enthusiasts know that driving on a back road is all about applying what is taught not in driver’s ed, but at race and high-performance driving schools around the world—balance and weight transfer. On a racetrack, controlling turn-in and rotation has more to do with right foot control than steering inputs. The Lexus GS 450h can’t be steered with the throttle nearly as well as the 550i. By design, the fuel-efficient CVT provides little engine braking, even when manually shifted into one of its lower gear ratios. (This feature seems to be less gear ratio selection as it is increased engine braking.) The 550i, on the other hand, is built for sporty driving. Once off the freeway, the 550i really shines. The performance numbers hint at its superior sporting attributes, pulling nearly 0.10g more and running a full 4.6 mph quicker through the slalom.

And the Lexus can’t hold a candle to the feedback of the BMW chassis. The standard variable-ratio steering on the Lexus is similar to a system from BMW, one that is gladly absent from the 550i. The system is fine for thoughtless meandering in a parking lot. Yet at speed the system is vague and does not accurately represent the steering angle of the front wheels. It needs an “off ” button.

There is no competition when it comes to ancillary vehicle functions. The Lexus is far superior with an easy-to-use touch screen. iDrive in the BMW is a capable interface, but it’s not intuitive, quick or practical. It has improved since its introduction, but it is still an inconvenience. A driver should be able to press one button to select a radio preset—not have to press the same button five times!

Both cars offer suitably luxurious interiors of wood and leather, but the BMW is more of a sports sedan in the classic sense. Either would be suitable for long drives; however, the drone of the Lexus engine is much less pleasant than the throaty 550i’s V-8. Passengers will be equally comfortable in both. One glaring issue with the GS 450h is the amount of trunk space consumed by its battery pack. There is more trunk space in a Z4 roadster than in the GS 450h. The 550i has nearly double the Lexus’ capacity.

The final tally: These two cars are of different lineage and are not true competitors. Even the premium price of the BMW shows this. The GS 450h is an intriguing design that has hopes of becoming a sports sedan…but it’s not. When comparing the two it is easy to distinguish which has race-car lineage and which wants to be a space pod. The future is coming, but for now my preference is for the new with a link to the past.