Lexus RX 450h 2009 Review

Lexus RX450h

What we liked
>>New line-up and pricing
>>Fuel economy claims

Not so much
>>Real world economy
>>Powertrain lacks punch

Overall rating: 3.0/5.0
Engine/Drivetrain/Chassis: 3.0/5.0
Price, Packaging and Practicality: 3.5/5.0
Safety: 3.5/5.0
Behind the wheel: 3.0/5.0
X-factor: 3.0/5.0

About our ratings

OVERVIEW
-- completing the RX range
As we mentioned in our original launch review of the new RX range (more here) this is an important model line for Lexus. The same applies to the new RX450h -- not only is it the updated hybrid model, but for the first time the brand is offering a range of the petrol-electric variants that mirror the petrol line-up.
 
Lexus is targeting 60 sales per month from the three-model RX450h line-up -- which will account for roughly 30 per cent of all RX sales. And the company is feeling confident about hitting that target as pre-orders have already accounted for the first two months of Australian production. Of those pre-orders Lexus Australia Chief Executive John Roca admits 75 per cent are already Lexus owners -- many of which are upgrading from an older RX.

In a depressed market luxury SUV sales have remained reasonably bullish, so making sure the updated hybrid hits its straps will be crucial to a successful year. More than that, the success of the new three-specification 450h range will be a justification for going it alone down the hybrid path among the luxury crowd.

PRICE AND EQUIPMENT
-- when one becomes three
As mentioned above the new RX450h comes in a three-model line-up -- just like the 350. That means an entry level Prestige, mid-spec Sports and range-topping Sports Luxury that essentially share the same trim and finish as their conventionally-engined counterparts.

Thanks to a fuel economy figure of under 7L/100km, Lexus has been able to take advantage of consumption-linked Luxury Car Tax concessions. Lexus claims that the tax break translates to a $4000 saving across the range.

The knock-on effect of the LCT allowance and new line-up means Lexus has been able keep the start price of the 450h under $90,000. The Prestige is priced from $89,900 (price guide; not including statutory and government charges), with the Sports on sale from $96,900 and the Sports Luxury beginning at $107,990.
 
For more information on the equipment see our original RX launch review.

MECHANICAL
-- no stone left unturned
Not surprisingly, this is where the 450h varies most dramatically from the 350. The Lexus engineers, led by Takayuki Katsuda (who attended the local launch), have given the petrol-electric hybrid powertrain a complete overhaul.

Under the bonnet there is a new 3.5-litre V6 petrol quad cam engine with dual VVT-I that replaces the 3.3-litre V6 single VVT-I engine from the 400h. It produces 183kW at 6000rpm and 317Nm at 4800rpm and drives the front-wheels. The rear-wheels are driven by a new electric motor that boosts the combined maximum power of the 450h to 220kW. Lexus calls this system E-Four (or Electric All Wheel Drive).

The new engine -- known as 2GR-FXE -- also adopts Atkinson cycle combustion as part of Lexus' pursuit of greater efficiency. The Atkinson cycle (also known as high-expansion cycle) is also featured on Prius's four-cylinder engine and works by making the expansion stroke longer (in duration) than the compression stroke in the combustion chamber. The downside of this system, over conventional (Otto) cycle engines, is that it has a negative effect on low-end torque. But thanks to the hybrid system that loss of torque is offset by the instant torque from the electric motor.

The hybrid system has been given a working over by the Lexus engineers resulting in every component being lighter. The Power Control Unit that acts as the brain of the hybrid powertrain has been redesigned for greater efficiency and reduced weight.

The same is true of the battery packs which have also been redesigned. The nickel metal hydride batteries are 1.5kg lighter and are small enough to fit underneath the rear seats.

All of this power is transmitted to the wheels via an Electronic Continuously Variable Transmission (E-CVT) that Lexus claims has no slippage courtesy of new software for the 450h.

All these features add up to give the 450h its signature piece: fuel economy figures in the same league as four-cylinder compacts. The claimed fuel consumption is 6.4L/100km on a combined cycle with an urban figure of 6.4L/100km. But Lexus is most proud of the highway figure -- 6.1L/100km -- which it claims demonstrates that hybrids can also excel on the open road.

PACKAGING
-- spot the differences
Beyond the regular RX updates over the previous generation model the 450h gets a number of exterior and interior touches to separate it from the RX350.

Externally there is a unique grille and front badge with blue tinting. The front bumper has been given a special style for the 450h as have the headlights and blue-tinted rear lights. Internally the subtle changes continue with the dials lit in blue and the tacho replaced by a dial explaining the hybrid power delivery.

Again, check out our RX350 local launch review for more.

COMPETITORS
-- more than Lexus likes to think
Lexus likes to claim the RX450h has no rivals -- expect for the outgoing 400h. The reality is that simply isn't the case -- as mentioned previously the luxury SUV segment has so far remained better off than most in the current climate and that is largely down to an array of new product.

In terms of size, the new RX range sits closer to the BMW X5 and Mercedes-Benz M-Class than its last iteration. Roca admits the X5 diesel range will be the most likely rival for the 450h but there are newer players that could cause Lexus trouble. Although slightly smaller in size the Audi Q5 and Volvo XC60 are available with diesel engines that offer comparable fuel economy.
 

ON THE ROAD
-- hybrid adds more punch to well-sorted package
Lexus was kind enough to begin the launch for the 450h at Sydney's Eastern Creek Raceway and allow the assembled media to sample the new model back-to-back with the superseded 400h. It is a rare occasion when car companies allow such dramatic comparisons between old and new and a clear sign that Lexus is confident in its new model's abilities.

The idea of the exercise was to demonstrate how extensive the dynamic changes have been to the new car. Although there were a number of subtle differences between the two, the most noticeable improvement on the new car was better stability under heavy braking. On the flip side, the extra weight of the new car (approximately 120kg over the 400h, according to Katsuda) was equally noticeable. The result of the extra weight was a slight dulling of the car's responses, particularly when changing direction.

Out on the open road, the launch drive took us from the racetrack through western Sydney and into the start of the Blue Mountains. It was a drive made up of a wide variety of driving conditions (city, country, climbing, twisty, open) -- a perfect drive to test the car's impressive fuel economy claims.

Unfortunately the 450h failed to live up to the much-hyped sub-7L/100km mark. The best result among the fleet was 7.4 while the worst was 10.4 with the average working out at 8.6. Personally I was able to achieve 8.1L/100km, with what I considered a typical driving style; neither driving conservatively nor quickly.

While those numbers are good for such a large car, they are considerably worse than the claimed figures and suggest that achieving the official numbers requires a particularly abstemious driving style.

Also falling short of the claims was the powertrain's performance. While there is no disputing it is a clever and efficient petrol-electric hybrid system, in terms of performance it leaves you wanting more. That's not to say the 450h is underpowered, but it is certainly not overpowered and is probably best described as having adequate power and torque.

It seems to have just enough to get the job done but without any punch or dazzle. In this regard it repeats the shortcomings we found in the conventionally powered 350.

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