MENTION the word hybrid and images of ultra-fuel-efficient vehicles with wind-cheating aerodynamics spring to mind. Toyota should be lauded for its effort in establishing and mass-producing the technology, with the Prius leading the way. Unfortunately, to many petrolheads the word hybrid is like a bucket of cold water to the face; they think of them as dull, uninteresting forms of transport. To disprove the validity of the latter statement, Lexus and BMW offer performance hybrid models in their respective GS (now for the second consecutive generation) and current 5 Series line-ups.
Styling
The exterior styling of the new GS range is a far cry from the conservative demeanour of the outgoing model. The aggressive F-Sport package (available only on the GS450h) includes a redesigned front bumper and mesh grille, 19-inch smoked-alloy wheels and a boot spoiler. The stance of the GS reminds us of the IS-F, but in a larger format.
BMW has taken a more conservative approach; from the outside, the ActiveHybrid is almost indistinguishable from other 5 Series models. There are a few ActiveHybrid logos scattered round the bodywork, with the most pronounced examples to be found on the C-pillars. Unfortunately, the alloy wheels that were specially developed for the ActiveHybrid are not available in our market.
Powertrain
The ActiveHybrid utilises the same 225 kW/400 N.m turbo-petrol engine as found in the 535i. A 40 kW electric motor is cleverly packaged inside the bell housing of the eight-speed conventional automatic transmission and pushes the total power figure up to 250 kW. The combined maximum-torque figure is 450 N.m. The inclusion of an advanced lithium-ion battery pack behind the rear seats adds just 47 kg to the mass.
The GS uses the naturally aspirated 3,5-litre V6 from the GS350 but the engine is further optimised for fuel efficiency (see The quest for efficiency). The outputs of 213 kW and 345 N.m are lower than those in the GS350 but the addition of a 147 kW/275 N.m electric motor powered by a more conservative nickel-hydride battery pack raises the total power output to 252 kW (the combined torque figure is not stated, how-ever). The Lexus drivetrain also features a continuously variable transmission (CVT) that allows the engine to run at optimum speed and load points to reduce fuel consumption.
Performance
The term performance hybrid may sound oxymoronic, but these two vehicles go some way towards justifying the nomenclature. In planning the photoshoot for this comparative test, we initially settled on a green theme but soon realised that this would not reveal the true characters of our protagonists. Instead, we opted for a quiet but dynamic stretch of road to let the vehicles’ true colours shine through.
The BMW was quick to find its stride but the GS450h needed more persuasion to misbehave. The fact that the charge-and-discharge instrument display changes to a red rev counter when sport+ mode is selected does add a naughty streak to the Lexus.
On the test strip, the BMW posted an impressive 0-100 km/h time of 5,79 seconds, which is 0,5 seconds quicker than the 535i we tested in August 2010. The kilometre marker was passed after a brief 24,91 seconds at a terminal speed of 218,41 km/h.
Unfortunately, the racy looks of the Lexus do not aid performance; the GS450h trailed the Bavarian with a 0-100 km/h time of 6,60 seconds and a kilometre time of 26,24 seconds at 208,71 km/h. These are still very impressive figures for a large luxury saloon.
While the BMW feels sporty as it accelerates through its eight gears, the calmer Lexus wafts the driver along on a wave of power through the CVT gearbox. It’s one of few applications of this type of gearbox that did not annoy us.
Economy
Performance and economy are mostly exclusive in the motoring world, although hybrid technology often promises substantial fuel savings. Has the addition of electric powertrains transformed these tar burners into fuel misers? Almost, but not quite. The CAR fuel-index figure for the Lexus and BMW stand at 7,4 and 8,4 litres/100 km respectively, which is still much better than their petrol-powered equivalents. The fuel-route figures are more closely matched at around 8,0 litres/100 km. After two weeks of intensive testing, the Lexus just edged the BMW in the economy stakes.
Both manufacturers claim their vehicles are true hybrids in the sense that they can run on electric power alone. BMW states that the 5 can travel up to 4 km and at speeds of up to 60 km/h in electric-vehicle (EV) mode if the battery is fully charged. The GS450h is also capable of driving only in electric mode at low speeds, but many testers commented that they could not achieve the same speeds or distance as they did with the BMW in EV mode.
Ride and handling
Both hybrids employ active damping systems that can be altered between comfort and sport settings. Notably, the Lexus boasts a four-wheel-steering system (the rear wheels can turn up to two degrees) that cleverly analyses vehicle speed and turns the rear wheels in the same direction as the front ones to aid stability during lane changes but turn the rear wheels in the opposite direction to shrink the turning circle at parking speeds. Overall, the Lexus provides the more comfortable ride.
Although the BMW has more conventional suspension and steering technology, it dishes up sportier responses and a more planted feel when pushing through bends.
Both vehicles performed excellently during the 10-stop emergency-braking test routine.
Creature comforts
Surprisingly for a German car, the BMW comes extremely well equipped. The ActiveHybrid has four-zone climate control, sat-nav, PDC, a reverse camera, rear-screen electric sun-blind and electric seat adjustment as standard. The options list is as long, and being overzealous in ticking the boxes will see the base price skyrocket. Its cabin is generic-BMW but none the worse for it, with carefully chosen materials and tight build quality.
Lexus owners will have to make do with only dual-zone climate control but they do get a few features in addition to those of the BMW, including head-up display. Where the GS450h outshines the 5 is with its 12,3-inch display screen (said to be the largest ever fitted to a production vehicle) compared with the latter’s 9,2-inch unit. This system is controlled with the remote-touch interface, in effect a sliding tab that mimics the behaviour of a computer mouse. Some of the team complained that it was not that easy to use and the majority preferred the BMW’s simpler iDrive-controlled setup. The Lexus seriously impressed with a classy cabin that some felt employed better materials than the BMW’s.
Generally, luggage space is compromised in a hybrid due to the storage space needed for the electrical hardware. The BMW’s boot measures 304 dm3 (down from 368 dm3 for the 535i) and the Lexus’s displaces 376 dm3 (we’ve yet to test a GS350 to accurately measure the change). In both cases, the rear bench is fixed and cannot be folded flat.
In terms of interior space, the GS450h offers 30 mm extra kneeroom for rear-seat passengers, and neither vehicle will leave four adults complaining about space.
Test Summary
The Lexus feels like a traditional hybrid because it is more suited to cruising than attacking a mountain pass due to its laid-back CVT transmission. This does not mean that it is dull to drive, however; it easily despatches slow-moving traffic when overtaking while delivering impressive consumption figures.
The 5, on the other hand, is testament to BMW’s expertise in building drivers’ cars because it introduces hybrid technology without diluting the sporty feel of the 535i. Were it not for the EV and clever coasting modes, it would have been almost impossible to notice that it is a hybrid.
At the end of the test, neither vehicle established itself as an outright winner. It will be personal taste and brand affection that finalises the purchasing decision.
That said, we remain sceptical about hybrid vehicles because of the complicated nature of the technology and the cost of the battery packs if they fail (upwards of R50 000 on these vehicles). This may negatively impact resale value but, for some peace of mind, Lexus offers an eight-year warranty on its battery pack and BMW five.
Lastly, the test team struggled to get past why a buyer with a guilty conscience would not rather opt for a well-sorted turbodiesel with similar perform-ance but even better fuel-consumption figures. Something like a 535d, perhaps?
