With the slow demise of the diesel engine amongst passenger cars, we are witnessing the electrification of various petrol-powered models. This is evident in the Lexus IS range, which now features a turbocharged petrol model, a petrol hybrid model and the more traditional, naturally aspirated V6 petrol model.
While the IS range is due for replacement early in 2021, the current line-up still represents fantastic value. Since the IS represents a premium take on a compact executive saloon, it must offer good driving dynamics, luxury, comfort and performance, something which is heavily affected by the powertrain. Here is a comparison of the three engine and gearbox combinations in the local IS line-up.
The figures
|
|
Lexus IS 300 EX |
Lexus IS 300h SE |
Lexus IS 350 F-Sport |
|
Engine |
2.0-litre, 4-cylinder, turbo petrol |
2.5-litre, 4-cylinder, petrol with an electric motor |
3.5-litre, 6-cylinder petrol |
|
Power/Torque |
180kW/ 350Nm |
164kW/ 221Nm +e |
232kW/380Nm |
|
Transmission Type |
8-speed automatic |
CVT automatic |
8-speed automatic |
|
Driven wheels |
Rear |
Rear |
Rear |
|
Boot volume |
480-litres |
450-litres |
480-litres
|
|
Fuel Consumption(claimed) |
7.5 L/100 km |
5.0 L/100 km |
9.7 L/100km |
|
0-100km/h |
7.0 seconds |
8.5 seconds |
5.9 seconds |
|
Price |
R747 800 |
R843 000 |
R880 500 |
Related: Is the Lexus IS good for families? Here’s our verdict.
Three models, three engines
The IS line-up reads like an evolution of the internal combustion engine, offering a large capacity naturally aspirated V6, a turbocharged in-line four-cylinder and a naturally aspirated in-line four-cylinder engine that works in conjunction with an electric motor.
Related: Lexus IS vs Alfa Romeo Giulia vs Jaguar XE: which one is the best value for money?
The petrol models
The petrol engines within the IS range are quite different, despite both sharing an 8-speed automatic gearbox. The turbocharged four-cylinder provides peak torque between 1 650-4 400 r/min and peak power at 5 800 r/min while the big V6 is lazier, offering peak torque between 4 800-4 900 r/min and peak power at 6 600 r/min.
The vast difference in the way that the two produce their respective figures means that aside from aural differences between the two engines, they also provide a very different driving sensation and varied performance. As expected, the claimed consumption for the smaller turbocharged motor is 2.2 L/100km better than the V6 which fights back with a 0-100km/h time that is 1.1 seconds faster.
The hybrid
Hybrid powertrains are always strange to report on as the power produced by the engine and electric motors individually cannot simply be added to one another for a combined output. This is because an electric motor produces its power and torque instantly while an internal combustion engine produces its power and torque higher up in the rev range, meaning that in the case of the 300h, there is 133 kW from its petrol engine while the battery in the boot boosts this to 164kW while reducing its space by some 30-litres. Torque is what the petrol engine produces, 221 Nm plus what the electric motor can provide.
The hybrid also has the benefit of being able to drive in all-electric mode if the battery has been sufficiently charged by the petrol engine. The dual-motor set-up means that the hybrid provides excellent fuel consumption and respectable fuel returns while being exempt from CO2 emissions. The hybrid is also the heaviest of the three, coming in at 1 720kg, some 40kg more than the turbocharged model and 35kg more than the V6.
Analysis
The three models on offer within the IS range are very different in terms of what they offer the driver. The naturally aspirated V6 will likely prove the more enjoyable car to drive, with a rev-happy motor that sounds the part and provides the best performance of the trio.
The hybrid represents the best environmental credentials but loses out on boot space and in the performance stakes thanks to its CVT gearbox, high kerb weight and low power output. The turbocharged model sits between the V6 and the hybrid, offering respectable fuel returns and accessible performance while coming in at the lowest list price, despite being the most basic of the three in terms of specification.
Verdict
Having looked at all three powertrains available within the current Lexus IS range, it becomes apparent that the IS 300 EX, with its turbocharged petrol engine, provides the best middle-ground in terms of fuel consumption and performance while being available with the lowest list price, making it’s the winner of this comparison.
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