Lexus RX 400h: The Compromise-Free Hybrid

Author's Rating:

Pros: Rich interior materials, Camry fuel economy, cushy seats, better to drive than the RX 350.

Cons: Smallish cargo area, no third-row seating, priced $5,000 higher than a similarly-equipped RX 350.

The Bottom Line: 
The 400h adds better fuel economy and an improved driving experience to Lexus' already-excellent RX. It's arguably the first hybrid to let buyers have their cake and eat it, too.

Author's Review
Background

Two years ago, I dodged a bullet. My fiancee’s mother had decided to buy a luxury SUV, and I was appointed the task of finding just the right one. I fretted. I researched. I fretted some more. And finally, given her priorities of comfort, convenience, reliability, and fuel economy, I recommended the Lexus RX 330.

Happily, the Lexus was a big hit. But after two years of ownership, with an average fuel economy of 18 MPG, environmental and political concerns had whittled away at my mother-in-law’s conscience. She was itching to get into a hybrid car, but it had to sit up high, and she wasn’t ready to give up the trappings of a premium brand. So, I had a new task: figure out if that hybrid RX, the 400h, was any good.

Now, keep in mind, we’re a hybrid household—a 2005 Prius is our daily driver—but I don’t recommend hybrids to everyone. Besides being costlier than their gas-only counterparts, hybrids typically involve compromises: weak acceleration, vague computer-mediated controls, econo-grade interior trim, or some combination of the three. So, when I test-drove the 400h, I expected its thrift to exact a toll on the RX’s other virtues. I was in for several surprises.


Surprise #1: Better Performance Than The RX 350

Coming into this test-drive, I knew that the 400h would be faster than my mother-in-law's RX 330, because its Hybrid Synergy Drive adds three electric motors to the 330’s 3.3-liter V6, for a total of 268 horsepower. But the conventional RX—now dubbed the RX 350—is even more powerful, having received a larger 3.5-liter, 271-horse V6 for 2007. So why should the hybrid feel faster?

Chalk it up to those electric motors. Unlike gasoline engines, which must be revved to perform, the 400h's electric units produce peak power and torque starting from 0 rpm. So when you apply the throttle from a stop, you get instant, urgent tug, the kind usually associated with large V8s. The difference isn’t just qualitative, either: in Car & Driver’s 5-60 mph acceleration test, the 400h’s time was nearly a half-second quicker than the 350’s.

How does the interplay between the 400h's gas and electric powerplants feel? Surprisingly, there's not much to feel, as drivetrain transitions are much quicker and more seamless than in previous efforts. As in the Prius, the RX's gas engine runs briefly at start-up, but shuts down once warm, allowing you to whoosh around slowly on electric power. At legal speeds, the gas engine phases in and out to provide additional punch--and when you nail the throttle, the system's creamy torque escalates to a mighty shove.

It's also difficult to criticize the V6's refinement. It emits only a muted hum in routine driving, and it revs with glassy smoothness through most of the midrange. Pressed hard, this V6 does feel cobbier than the one in Mercedes' M-Class, but it's hardly objectionable.

As for the 400h's raison d'etre--fuel economy--one can only expect so much from a swift, powerful vehicle carrying 4,500 lbs of curb weight. Still, real-world fuel economy is just a touch over 25 MPG, which nearly doubles some rivals' mileage. Fuel savings are unlikely to cancel out the price difference between the RX 350 and 400h, but then, no one buys a $45,000 SUV to pinch pennies.


Surprise #2: A Better Transmission Than The RX 350

Like most hybrid vehicles, the RX is only available with a CVT, or continuously variable transmission. If you're unfamiliar with this technology, you'll find the CVT similar in operation to a conventional automatic transmission, but with an eerie absence of up- and downshifts. Instead, your throttle foot simply acts as a rheostat for revs--floor the pedal, and the engine hangs at peak rpm while the car gathers speed.

Now, up until this drive, I'd never much liked CVTs. But I'd only sampled them in low-powered cars, such as the Prius and Dodge Caliber, where even moderate throttle applications can lead to a busy, raucous spike in revs. In a powerful vehicle like the 400h, it's a different story. The engine barely stirs in gentle driving, and with so much thrust on tap, it becomes fun to feel engine speed race ahead of road speed, as if you're throttling up a jetliner for take-off.

One quirk: in Reverse, the 400h runs only on its electric motors, with no gas-engine assistance. As a result, owners must learn to dip deeply into the throttle to back out of downhill-facing parking spaces.


Surprise #3: Better Handling Than The RX 350

This was the one that baffled me, as the RX 400h's spec sheet suggests that it should handle worse than its gas-only sibling. It's about 300 lbs heavier than the RX 350, for one thing. And besides that, it uses an electric-assist steering system, a technology that has cursed scores of recent Chevys, Pontiacs, Saturns, Hondas, and Toyotas with numb, limp, unnaturally-weighted helms.

Against all odds, though, the RX 400h is actually among the better-handling SUVs in its class. Its electric steering doesn't approach the meaty, communicative feel of the BMW X5's, but its responses are reliably accurate, and the wheel offers a moderate, well-judged heft. Ironically, the RX 350's conventional hydraulic steering feels unnatural by comparison, owing to its lighter effort and looser sense of straight-ahead.

The 400h won't keep up with a BMW X5 in the twisties, either, but for a vehicle with zero sporting intent, it's a very competent handler. The 400h's suspension is a skosh stiffer than the RX 350's, which not only helps overcome its added poundage, but also takes some of the "Lexus wobble" out of initial turn-in. On challenging roads, the 400h is comparable to Mercedes' ML350: the chassis is clearly out of its element, but remains secure and surprise-free, with adequate reserves of tire grip.

As for braking, Lexus deserves a round of applause for its work on the 400h's regenerative braking system, which uses energy released during braking to recharge the electric motors. In most hybrids, this technology obliterates brake-pedal feel and makes smooth stops difficult. But the 400h's pedal, while still light and soft, actually feels more linear than the 350's.


Surprise #4: A Better Ride Than The RX 350

Well, actually, I should qualify that statement: the 400h rides better than its sibling if you prefer a firmer, more sports-sedan-like ride. Don't get me wrong, the 400h is still among the comfiest-riding SUVs in its class, and its suspension is only subtly tighter than the RX 350's. But if you've got a bit of car enthusiast in you, you'll appreciate the 400h's greater resistance to pitch and bobble over small bumps.

And even if your definition of luxury is more "Buick" than "BMW," the 400h's ride should suit you just fine. Its structure is impressively stiff, transmitting few of the high-frequency jitters and rattles that mark most SUVs. Noise levels are hushed, too, and you'll never tire of the silence that falls over the cabin when driving in electric-only mode.


Inside Story

The surprises are over from here on out, as the 400h's interior is mostly identical to the 350's. Panel fit is impeccable, and the trim is comprised of silky leather and soft-touch, upscale plastics. As for the styling, there's a "techy" flavor to the RX's cabin that you won't find in its European rivals. Its dash is trendier, with sharper angles and more metallic trim. The resulting ambiance is perhaps less classy than a BMW's or Mercedes', but arguably more interesting.

The Lexus also holds an advantage over the European makes in terms of ergonomics. The electroluminescent gauges are extremely legible, and most of the controls are about where you'd expect them to be. The functions of the stylized center-stack buttons aren't immediately obvious, but they're at least large and well-marked. An LCD screen in the center of the dash displays fuel economy, power flow, and--if so equipped--navigation and reversing-camera readouts.

You survey these instruments from a supremely comfortable driver's seat, which feels nicely propped up and offers good support. As in many Toyotas and Lexuses, the steering wheel seems angled a bit towards the horizontal, but the tall driving position feels natural otherwise. Forward visibility is fine, thanks to the relatively low cowl, but the rising beltline and thick, overstyled rear pillars create a pinched view aft.

There are fewer nits to pick in the RX's rear seat, which is among the best in this class. The bottom cushion is nicely elevated, offering good thigh support, and there's plenty of legroom for six-footers. The rear bench also slides fore-and-aft, with individually reclining backrests, so two passengers can lounge in limo-like comfort if there's nothing in the cargo bay. The seat isn't wide enough to accommodate three adults without squeezing, though.


Fill 'Er Up

Like most SUVs, the RX 400h discredits the "utility" portion of its "sport-utility" moniker by failing to offer a third-row seat. This limits passenger capacity to the same five occupants accommodated by any conventional sedan. So, if an extra couple of seats would make your life easier, consider the seven-seat Acura MDX, Cadillac SRX, or Lexus GX 470.

You may also want to shop around if cargo space is a high priority. The 400h's trunk isn't dinky by the standards of its class, but it's higher off the ground--and not appreciably roomier--than a conventional station wagon's. The wide rear suspension towers reduce floor space, and the dramatically sloped rear glass threatens to crush bulky cargo as the tailgate is shut. Fortunately, a split-folding rear seat is standard equipment, so tall items can be pushed well forward to fit inside.


Ownership

Like virtually every car in the Toyota/Lexus family, the RX 400h has racked up an enviable reliability record in the short time it's been on the market. In fact, consumer surveys list the RX among the most reliable midsize SUVs on the market, along with the Acura MDX and Infiniti FX. This partly explains the high customer-satisfaction scores that those same surveys often note.

In addition to the promise of trouble-free operation, the RX also holds its value much better than the average new vehicle, and is sold through one of the cushiest, most attentive dealer networks extant. Crash-test scores are superb, abetted by standard head-curtain airbags and stability control.


In Sum

I'm normally not one to wax rhapsodic about luxury SUVs, but I'll admit to being a little starstruck by the 400h. Blame the exceedingly well-integrated hybrid technology. For about $5,000 more than a similarly-equipped 350, you get reduced emissions, the fuel economy of a Camry, and generous helpings of added interest and novelty, plus stronger performance, sportier handling, and tighter steering and brake feel. If the eco benefits don't justify the extra cost, the dynamic improvements certainly do.

That price premium, too, must be put into context. With MSRPs ranging from $45,355 to $50,085, the RX 400h is still cheaper than equivalent rivals from Audi, BMW, Mercedes-Benz, Porsche, Volkswagen, and Volvo.

Taking all of this into consideration, I was quick to recommend the 400h to my mother-in-law. A white FWD model now shares driveway space with her RX 330, and aside from a few grumbles about the firmer ride, my position as family automotive advisor appears safe for the time being.

In fact, unless your top priority in a luxury SUV is sportiness--in which case I recommend the BMW X5--I can't imagine anyone being dissatisfied with the 400h. The RX, in non-hybrid form, was already the most competent all-rounder in its class, making it an obvious choice for most buyers. Adding family-car fuel economy and more-carlike road manners only sweetens the pot--and, in my judgment, sends the 400h straight to the head of this class.