THOSE familiar with the Lexus performance hybrid may be surprised to learn that the new IS Hybrid isn't supposed to be one in the strict sense of the term. A petrol-electric model from the Japanese luxury carmaker usually has prodigious performance, courtesy of the stonking torque produced by the Lexus Hybrid Drive System.
For the Lexus IS300h, an emphasis on eco-friendliness means its power and torque are slightly lower than the IS250 with its 2.5-litre petrol engine.
The IS300h is the first hybrid variant to be offered for this compact saloon model. This third-generation IS uses a platform based on the GS mid-sized sedan with a body built by high-tech methods to make it stronger and stiffer. Its hybrid powertrain, on the other hand, is largely taken from the front-wheel-driven Toyota Camry Hybrid and modified for the rear-wheel-drive IS with the requisite Lexus refinement.
But like other Lexus hybrids, it is a full hybrid which can operate in petrol or electric modes alone, as well as a combination of both. To maximise fuel efficiency, the IS300h gets a four-cylinder petrol engine instead of the IS250's V6. The 2.5-litre Atkinson cycle engine is mated to a high-power electric motor to drive the rear axle via a continuously variable transmission.
What is interesting about the IS300h is that - in a first for Lexus - the nickel-metal hydride battery is located below the floor instead of in the boot; this means it does not eat into luggage space like in other Lexus hybrid sedans.
A direct consequence of this configuration lies in the hybrid's front/rear weight distribution. While the petrol-engined IS250 has 54:46 front/rear weight distribution, the IS300h's is almost 50:50. This near-perfect weight distribution was achieved partly with the help of the lighter four-cylinder engine in front; the result is the hybrid is better balanced, which benefits handling immensely.
So although it weighs in at about 1,700 kg, or 80 kg more than the IS250, the IS300h is an engaging drive. At the same time, the dynamic parameters have changed because the lighter nose allows for the use of softer front springs, making the IS300h both comfortable and controllable.
Despite not being a performance hybrid, the powertrain is still capable of sporty response, especially when using the steering wheel-mounted paddle shifters. Six steps have been programmed into the CVT so that it feels and shifts manually like a conventional automatic transmission.
It also sounds suitably sporty, thanks to an interesting new feature called Active Sound Control (ASC). Using a dedicated loudspeaker, Lexus is able to "compliment" the engine noise with audio sound. Thus, during acceleration and deceleration, ASC delivers the appropriate engine sounds - even when the engine is turned off and the hybrid is operating on electric motor power alone.
The only time ASC is automatically deactivated is when two drive modes - Eco and EV - are selected. Eco maximises hybrid system efficiency and fuel economy; EV allows the IS300h to run solely on electric power for silent operation and zero fuel consumption and emissions. And it can be exceptionally frugal.
Lexus claims a fuel consumption figure of 4.9 litres per 100 km under the combined cycle - an amazing 20.4 km per litre; carbon dioxide emissions are 113 g/km, or a full 100 g/km less than in the IS250.
With this much clean, green luxury, who needs a performance hybrid?
Engine 2,494cc inline-4
Transmission Continuously variable
Max power 181 hp @ 6,000 rpm
Max torque 221 Nm @ 4,200-5,400 rpm
Motor Permanent magnet synchronous
Max power 143 hp
Max torque 300 Nm
Total system output 223 hp
0-100 kmh 8.5 secs
Top speed 200 kmh
CO2 emissions 113 g/km
Distributor Borneo Motors