2010 Lexus RX450h Review

2010 Lexus RX 450h

First drive: 2010 Lexus RX 450h

By Henny Hemmes
Senior European Editor
The Auto Channel
Amsterdam Bureau

It’s already a while ago, but I vividly remember my first ‘encounter’ with the Lexus RX 300. In 1998, our test route went through northern Michigan and we spent the night in a national park. The next morning, and for the first time in my life, I saw an eagle in full flight. It was a stunning sight. At that time Lexus was the first off-roader based on a car platform, a type soon to become known as a crossover.

And in 2005, Lexus was also the first with a hybrid off-road vehicle. In the mean time, all major car manufacturers are focussing on fuel efficient crossovers and Toyota’s luxury division has some serious competitors. That’s why I was really curious if the new 450h may be able to match or outperform other fuel sipping models, such as the BMW X5 3-liter diesel and the likes.

Until now, you could buy the RX350 with a 275 hp 3.5-liter V-6 or as RX hybrid with the Hybrid V-6. The 2009 model offers an upgraded version of the Lexus Hybrid System of the 3.5-liter V-6 and two electric motors, besides the RX350 with the normal petrol engine.

Lowest CO2 in class

The exterior of the 2010 Lexus RX 450h is of a new design, but the body sits on the platform of the Toyota Highlander. That allows for the same set up as before, with the CVT with an electric motor and a second electric motor in the back axle. The CPU, the management system is lighter and more efficient and the 279 hp strong V-6 is more efficient too. Lexus claims a reduction of be 23 percent in fuel consumption.

In the second generation 450h, the system’s total power output has been raised with 27 hp to 299 hp and , more than the Mercedes ML, Audi Q7 and abovementioned X5. But that is not the most important achievement of the R&D engineers. A slew of modifications in the power plant and the electric motors resulted in very low emission figures. With only 148 gram CO2 per kilometre, the Lexus RX 450h has 23 per cent less emission and 10 per cent more power than the outgoing model. In California the 2010 model earn the SULEV (Super Ultra Low Emission Vehicle) status (Tier 2-Bin 3 in other states). With such low CO2-emission the 450h by far beats the Mercedes ML 450 Hybrid (185 g/km) and the successful Mercedes ML 320 CDI (245 g/km).

Hi-tech hybrid system

One of the measures that pays off for the new Lexus hybrid is the new V-6 engine running on the so-called Atkinson cycle. This allows the intake valves to open longer and the exhaust valves to be closed for a longer time, thus making more effective use of the fuel. Lexus also uses cooled Exhaust Gas Recirculation (EGR), the cooling of the exhaust gasses to drop from 880 to 150 degrees Centigrade. Exhaust Heat Recovery (HER), the use of the remaining heat to allow the engine to reach its work temperature much faster, allows the system to switch into electric mode much faster.

New are the three driving modes, Eco, EV and Snow. The Eco mode is linked to an indicator in the speedometer and provides a modified throttle action and air conditioning control to support the driver to drive ‘economical’. In EV mode the 450h automatically operates under electric motor power. This happens from the start up to 25 mph. You can also select this mode yourself with the multi-information switch on the steering wheel. The same switch allows you to choose Snow mode. Then the pressure on the throttle is automatically adjusted to reduce driving torque end wheel spin, while the rear electric motor is engaged to improve traction in case the front wheels spin.

Not much was changed with respect to the batteries. As before, the new 450h uses nickel-metal hybrid, that because of better cooling and a smaller size could be positioned in a different way.

The engine is teamed to a six-speed sequential CVT transmission, that works efficient, but allows for higher revs that you would expect normally during normal acceleration. There are three new driving modes, Eco, EV and Snow, that improve the fuel efficiency of the hybrid system and the driving performance. The EV mode is for driving on electric motor power exclusively, with no C02, nor NOx emission. The fuel consumption of the 450h is the lowest of any crossover SUV around, with 6.3 l/100 km for the combined cycle.

In Europe, the RX has a re-tuned suspension and power management for (according to Lexus) better acceleration while not much influencing the fuel consumption.

Over the top

When you take your seat, you recognize the improved quality in the cockpit and an new central control unit much like BMW’s iDrive for operating the new infotainment. Too bad, that it is ‘over the top’. The control unit resembles a computer mouse and it moves a cursor on the screen. It makes life behind the steering wheel more complicated as you will have to look where precisely the cursor ends and in case of navigation, you might be hitting the wrong spot quite easily. The only person who will like it, will be the one in the passenger seat. Lexus says it will be introduced in upcoming models. Maybe the Lexus engineers should think twice, as I believe it is bad for safety: the driver has to concentrate on the road and not on a screen…

No surprises

Driving the Lexus RX 450h brings no surprises. The hybrid system has lots of power and the CVT works seamless and smooth. However, when you push the throttle, the CVT takes a split second to respond as the engine revs are kept on the ideal level. A consequence is that engine noise is a bit pronounced. The large mirrors (a bit too large for a good view on crossings) are the reason for wind noise in the cabin.

When I spoke to Noahisa Hatta, the project manager product planning of the Lexus Development Center, he agreed that this is the case. But we have to blame European regulations. “Also the A-pillar was too heavy and that is why there are little triangular windows.”

Handling is better than in the 350h, providing a sure and safe feel on the Hungarian country roads. Our test car had the new Active Stabiliser System, which makes it easy and comfortable to deal with the twisty and sometimes not so well maintained tarmac. Even pot holes are dealt with in great (Lexus-)style.

Lexus expected us to drive ‘Eco’ on a certain stretch of the route, but I kept on going the way I normally drive. That would enable me to compare my fuel efficiency with other models in my same old driving style. Some colleagues did a real good run, with some 32 mpg, but my 26 MPG over the whole trip was really not bad, when you take into account a sporty driving style and some a vehicle weight of some 5,700 lbs.

The RX450h does its work well and meets the standards of a fuel efficient SUV with its low CO2 emission and good fuel efficiency. In Europe it’s price is higher than that of the competition, but the Lexus has a better standard equipment and is greener too, but the latter is something you must be willing to pay for.

Only a direct comparison with its competitors will show what model will be the benchmark in this class for the time being.

2010 Lexus RX 450h

Price: MSRP $ 43.250 (AWD). Base $ 41,660 (FWD) . Well Equiped $54,000
Engine: 3.5-litre V6 petrol + two electric motors
Power: 299 hp
Performance: 0-60mph: 7.6 seconds
Economy/CO2: 28.8mpg/148g/km (or 6.3 l/100 km)
Equipment: Electric 4WD, cruise control, electric front seats, dual-speed electric windows, dual-zone automatic climate control, leather seats, 19-inch alloy wheels
On sale: July 2009