Infiniti M35h, Lexus GS 450h and BMW ActiveHybrid 5 Comparison Test

OVERVIEW

In 2005 Lexus launched the world’s first RWD hybrid luxury sedan, the GS 450h. For the greater part of the years since, Lexus has had a monopoly of sorts on luxury hybrids.
The Japanese automaker today has four distinct lines with a hybrid model among them, and with one - the CT 200h - available only as a hybrid.
The midsized IS line, which has missed out to date, will also get a long-awaited hybrid variant later this year. By the end of 2013, the only Lexus that won’t be available with a petrol-electric powertrain will be the Landcruiser-based LX SUV.
That iron-clad grip on the luxury hybrid market was challenged in the latter half of 2012 with the arrival of the Infiniti M35h, and has since been followed by BMW’s ActiveHybrid 5 and ActiveHybrid 3.
With these fresh new entrants, now seems as good a time as any to see which one can lay claim to the title of “best luxury hybrid”.

The What's What

We’ve chosen to pit the GS 450h F Sport against the M35h and the ActiveHybrid 5.
Each have their own distinct advantages.
The Lexus has been on the market longest. Meanwhile the Infiniti M35h was, for a time, the world’s fastest hybrid with a 0-100km/h sprint time of 5.5 seconds (the BMW Activehybrid 3 took that crown last year with a time of 5.3 seconds).
The Infiniti is also the most affordable of this group, with a retail price of $99,900.
BMW’s Activehybrid 5 is backed by the Bavarian automaker’s reputation for fine-handling cars, and it's got one of the best engines in existence under its bonnet - the N55 3.0 litre turbocharged inline six.
All of them have claimed fuel economy figures of under 7.0 l/100km, meaning all qualify for a reduction in Luxury Car Tax.
All of them also have power outputs in excess of 250kW (so none could ever be described as ‘slow’).
But how do they drive? And importantly, with each offering express-saloon performance, what, if any, fuel economy benefits do they offer?
We took all on a 78km road loop through Melbourne’s CBD and inner suburbs, onto dual-carriageways and freeways out of town. To ensure parity, each car repeated the route three times with a different driver.
Each car carried roughly the same amount of fuel, and with a similar charge showing on the batteries.

Best Interior Luxury and Appointments

The Lexus gets off to a good start. It is sumptuously appointed and brimming with all sorts of high-tech features, leaving the other two (particularly the BMW) looking spartan by comparison.
The deep red leather (a no-cost option) of our GS 450h F Sport was sumptuous and flawless, and adorned the seats, door trims and much of the centre console.
The 18-way adjustable power front seats offer plenty of support and an absolutely huge range of adjustment. They’re also heated and ventilated.
In the back seat, legroom is a little short but otherwise head, shoulder and foot-room is good.
Radar-guided cruise control, keyless entry and ignition, a head-up display, automatic high-beam and a digital radio-tuner are among the GS 450h F Sports’ impressive standard feature set.

There’s also a glass sunroof, dual-zone climate control, keyless entry and ignition, reversing camera/radar, sat nav and Bluetooth/USB connectivity - all of the items that you’d expect to be standard on a car costing six figures.
And our tester had even more.
Equipped with the optional Enhancement Package, our GS 450h test car also came with LED headlamps, a thumping 835-watt 17-speaker Mark Levinson stereo and a gargantuan 12.3-inch infotainment screen.
Lavish, certainly, yet still cheaper than the BMW.
It’s a similar tale inside the Infiniti, although the execution is very different. The Infiniti’s organic exterior styling also carries over into the interior, and there are elements of the dashboard and centre console that seem unnecessarily curvy.
Inside, the seating is superb, the ride comfortable (the best of this trio for outright comfort, in fact) and with plenty of space for four adults.
The equipment levels are reasonable, although the ‘forest air’ ventilation is gimmicky, the eco-feedback accelerator is a pain, and the radar-based safety systems are far too eager and intrusive.

There’s loads of standard equipment - radar cruise control, bi-xenon headlamps, heated and cooled seats, they’re all there - but when driven back-to-back with the Lexus and the BMW, the M35h just feels a bit dated.
There’s simply too much carry-over from Nissan’s parts bin. Driven a Maxima, Murano or 370Z? You’ll recognize a lot of the M35h’s switchgear then, which isn’t a good thing for a stand-alone luxury brand.
Ultimately though, it was the BMW which trailed in this category.
Although scoring highly for its build-quality and finish, it does not fare as well when it comes to standard equipment and trim.

While the interior looks stylish, some of the plastics used don’t quite match the polished look or feel of the Lexus. The leather is also firm and not as appealing to the touch.
While the outboard seats in the BMW are good, the centre seat is too high for adults for long stints. The front seats are flat and lack the cosseting feel of the Lexus and Infiniti, and there’s no heated or ventilated seats as standard.

Nor is there keyless entry or a reversing camera as standard, which is preposterous considering this is the most expensive car in this test.
Boot space is something that also needs to be considered. All of these cars have massively truncated boot capacities due to the need to accommodate a bulky battery pack, and none have folding rear seats.
The Lexus leads the pack with its comparatively generous 465-litre boot, while the BMW and Infiniti trailed far behind with their boot capacities of 375 and 350 litres respectively.
The winner then, for interior Luxury and Appointments: the Lexus GS 450h.

1. Lexus GS 450h
2. Infiniti M35h
3. BMW ActiveHybrid 5

Best Performance

You’d expect the German to be the best driver’s car, and the ActiveHybrid 5 doesn’t disappoint. Forget about the “hybrid” part of the badge - this is very much not your Grandma’s Prius.
The ActiveHybrid 5 borrows its turbocharged 3.0 litre inline six and electric motor from the smaller ActiveHybrid 3, currently the fastest production hybrid in the world.
It’s a sweet unit, and thanks to the low-down punch of the electric motor, it produces massive thrust from the moment the accelerator is stomped.
But powerful though it is, the ActiveHybrid 5’s engine is outclassed by the silken 3.7 litre naturally-aspirated V6 of the Infiniti M35h.
The M35h’s power pack develops a combined total of 268kW, which handily eclipses the Activehybrid 5’s 250kW. In the sprint to 100km/h, it’s the Infiniti that crosses the line first, taking just 5.5 seconds against the BMW’s 5.9 seconds.
So, yes, the Infiniti is faster. But for handling, the crown is firmly with BMW.

The BMW impressed us all with its composure and rock-solid feel through corners. The Infiniti, on the other hand, feels under-damped, and there’s a lot of squirm from the tall sidewalls of its 18-inch tyres.
The biggest surprise however was the Lexus.
In F Sport guise the GS 450h is equipped with active rear steering, and cornering (particularly at lower speeds) is incredibly sharp.
Couple that with a willing 3.5 litre V6 and electric motor (combined output 254kW), and the GS 450h fires itself out of corners like a cannon. It’s sporty stuff, but unfortunately not quite as involving as the BMW.
The Lexus turns in very well, but it feels artificial compared to the ActiveHybrid 5. Mind you, the difference in cornering performance between the GS 450h and ActiveHybrid 5 is slim.

Transmission performance had the BMW’s fast-shifting eight-speed duking it out with the Infiniti’s impressive seven-speed. The Infiniti gearbox is every bit as good as the ActiveHybrid 5’s.
The CVT trans in the GS 450h, while great for urban driving, isn’t so easy to live with when being pushed. The typical CVT drone that results from firewalling the accelerator can be grating.
Final finishing order?
Best Performance Ranking sees BMW in first place, followed by the GS 450h then the Infiniti at the back, let down by soggy dynamics when driven against the much sharper BMW and Lexus.

1. BMW ActivHybrid 5
2. Lexus GS 450h
3. Infiniti M35h

Fuel Economy

This was where we had to get scientific. All three cars were driven over the same 78km route three times, with each driver swapping into a different car for each repetition.
Not all drivers are created equal, and while some of TMR’s staff are notorious leadfoots, others are adept hypermilers.
By having all of us cycle through each car, the total fuel economy recorded during the test should provide a meaningfully accurate real-world average.
None of the cars managed to come close to their listed average fuel consumption figures, but it was the Japanese contenders that guzzled the least.
The Lexus GS 450h was the clear winner with an average of 7.4 l/100km, while the Infiniti used 7.9 l/100km and the BMW quaffed 9.3 l/100km.
That’s against listed combined fuel economy figures of 6.3 l/100km for the GS 450h, 6.9 l/100km for the M35h and 6.4 l/100km for the ActiveHybrid 5.

The performance-focused BMW’s result wasn’t such a huge surprise, but, to be honest, we were expecting the gap between the Lexus and Infiniti to be closer.
Although the Lexus has the advantage of a more efficient CVT transmission, the Infiniti is the only car capable of cruising at 100km/h on battery power alone - something we felt would confer a tremendous fuel economy advantage.
But looking at their respective spec sheets, we think we know why the Lexus edges out the Infiniti.
The GS 450h’s electric motor produces 147kW and 275Nm - well above the M35h’s 50kW and 270Nm output under EV power.
That means the level of electric assistance available in the Lexus is much greater, and there’s less reliance on the petrol engine during the critical acceleration phase. Simply put, less load on the petrol engine means less petrol burned.
The BMW’s higher consumption may also likely be explained by the numbers; in the ActiveHybrid 5, there’s only 40kW and 210Nm of assistance under normal driving conditions.
So it’s Lexus on top. The final ranking:

1. Lexus GS 450h
2. Infiniti M35h
3. BMW ActiveHybrid 5

Verdict

Buy the Lexus. It’s a no-brainer.
It’s luxuriously appointed, exceptionally well-made, chock-full of gadgets and very efficient for a large luxury sedan.
It’s also far cheaper than the BMW and more universally appealing than the Infiniti M35h.
But the Infiniti is not without its charms. After all, at $99,900 it’s the only car here that retails for less than $100,000, and it offers nearly as much equipment as the $111,900 Lexus GS 450h F Sport.
The BMW, unfortunately, while a superb drive - and in isolation rewrites how a hybrid can feel at the wheel - its slim standard spec list and $122,900 sticker price count against it in this company.
And, on our test, It didn’t turn out to be particularly fuel efficient either.

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