For: Engine note, chassis balance, strong brakes, high spec
Against: Lack of proper limited-slip diff, hesitant gearbox, flat seats, fidgety ride
Background:
The IS-F is the first sports Lexus model to make production. It was the idea of two Lexus engineers, Yaguchi-san and Sakamoto-san, but it is not the first IS model to undergo a little light fettling. In 2003 the same engineers experimented with the previous-generation IS300 — normally fitted with a 3.0-litre straight six — to create the IS430 project car, with a 340bhp V8, adjustable dampers and a six-speed manual transmission.
But from here on you must forget what you know about traditional Lexus values – comfort, refinement and so on – because this new model has its priorities in an entirely different place. With petrol V8s and hybrids that deliver mountain-moving torque from idle, Lexus’s existing range isn’t exactly slovenly, but this, the IS-F, is the firm’s first stab at a fully paid-up sports saloon.
The ‘F’ stands for Fuji Motor Speedway, the Japanese track owned by Toyota and the venue for the car’s development. If any doubt remains, one look at the IS-F’s mechanical specification gives a clear indication of its market positioning.
A naturally aspirated 5.0-litre V8 producing over 400bhp and driven solely through the rear wheels is a strikingly familiar layout; both BMW and Mercedes have recently launched products that, give or take the odd cubic centimetre or brake horsepower, match the Lexus blow for blow.
And the £51,000 Lexus is charging for the IS-F places it neatly between the £49,310 M3 saloon and the £51,317 C63 AMG. That’s tough competition by any measure, but especially so when it’s your first effort.
Design
Although the IS-F shares its basic suspension with more mainstream IS models – double wishbone suspension at the front and a multi-link arrangement at the rear – Lexus has undertaken some serious tinkering to give the IS-F greater control.
The front suspension arms and steering knuckles are now constructed from lighter materials to reduce unsprung mass, the spring rates are increased, the anti-roll bars are thicker and the bump stops activate earlier, while the hub bearings are unique to the IS-F. The IS-F wears thicker and broader brakes (360mm at the front and 345mm at the rear), but unusually for a car with such driver-focused intentions, the IS-F employs electric power steering, and not a hydraulic system.
On first inspection the driveline package seems familiar, the 5.0-litre V8 providing the conventional power in Lexus’s range-topping LS600h hybrid. The eight-speed automatic transmission has also been seen before in the LS460 and GS460. Make no mistake, though, there has been some major tweakery. The result is a maximum output of 417bhp, 28bhp more than the LS600h, although torque slips slightly to 372lb ft.
The automatic gearbox in the IS-F benefits from bespoke ratios and a manual mode, operated either by the gear selector or paddles mounted behind the steering wheel. From second gear upwards the ’box operates a lock-up mechanism to give faster shifts and a more direct throttle response. It will also hold on to gears right to the rev limiter and only change down if the engine threatens to stall.
The IS-F has also undergone an extensive visual makeover. In addition to the beefed-up bumpers and bigger wheels (in this case 19-inch), the IS-F has a bonnet bulge that makes even the M3’s power dome look inadequate, broader sills and pumped-out front wheel arches complete with cooling gills.
On the Road
If there’s one area of this car where Lexus has absolutely nailed what a super-saloon should be, it’s under the IS-F’s borderline-ludicrous bonnet bulge. Freed from the refinement and economy shackles of its hybrid applications, this 5.0-litre V8 is far and away the most engaging motor Lexus produces.
The delivery itself is relatively peaky. Maximum power arrives at 6600rpm, passing the torque peak at 5200rpm, and with a 7000rpm red line this is a high-revving engine. At MIRA’s test track the IS-F couldn’t quite match Lexus’s acceleration claims, although 5.2sec to 60mph and 12.3sec to 100mph are very respectable figures.
But for all its revving, the IS-F’s powerband is not narrow enough to justify eight forward ratios. Left to its own devices, you’re aware that the ’box is making too many shifts.
The F rides just like a regular IS. It feels quite softly sprung but not softly damped; there’s a certain harshness and patter that, much like the standard car, means its ride at any speed never settles except on the smoothest of asphalt.
So on a demanding road the IS-F is slightly compromised. It is refined but does not quite control its body movements well enough. If it’s just the poise you’re after, the M3 and C63 deliver more here.
The IS-F’s overall chassis balance is very good, however. On smooth asphalt or a race track it is enjoyable and extremely exploitable. It turns in crisply, and while the steering is not overly engaging, it is accurate and direct.
A conventional limited-slip differential, rather than the F’s electronically controlled open diff, would make for smoother transitions back into line and improve traction. Better suspension control and an LSD would be enough to revolutionise what’s already a very entertaining car.
The IS-F’s brakes are excellent. Their feel and progression are good and, for a car weighing 1720kg, they have no problem routinely stopping the IS-F on a circuit.
Living
Much like in the M3 and C63, the hottest Lexus’s interior pretty much follows the themes set by the standard car. Dashboard architecture and materials are largely unchanged, save for some faux-metal finish on the centre console.
Unlike in the BMW and Mercedes, though, changes to the Lexus don’t amount to serious alterations to the driving furniture. Granted, the IS-F’s front chairs are subtly different from a standard IS’s, but not by enough; they don’t drop low enough and have insufficient lateral support.
The steering wheel is little different from that of the regular version. Its range of adjustment is limited; serious drivers will find they can’t bring it close enough to their body and that, when it’s at the uppermost reach of its height adjustment, it’s too angled (the bottom of the wheel is too close to the driver while the top is too far away).
Otherwise, the cabin is fine. Materials are acceptable, while fit and finish are beyond reproach. The touch-screen infotainment system is largely simple to use and, at the Lexus base price, comprises all the kit you would expect to be standard and a bit more besides.
Interior room? It’s at a premium in the rear of the cabin, but the boot is average for a car in this class.
Lexus hasn’t been shy in its pricing; the IS-F is pitched right between its rivals from Mercedes-AMG and BMW.
What does set the Lexus apart is that, typically, it wants for nothing in terms of standard equipment. If the IS-F maintains Lexus’s traditional ownership traits – and there’s no reason to think that it shouldn’t – then running an IS-F should be a remarkably easy, fault-free and fuss-free experience, albeit at a cost in depreciation; after just two years it’s predicted that the IS-F will have lost almost half of its value.
Verdict: 3.5 / 5
The IS-F is a credible effort for a company whose stock in trade is luxury and refinement, and there is much that Lexus has absolutely nailed. The V8 powerplant stands comparison with any of its rivals and the overall balance of the IS-F’s entertaining and adjustable chassis is wonderful. Those are the basics and they’re spot on.
In the end, then, it’s details that set the Mercedes C63 and BMW M3 apart from the IS-F. But they’re the details that separate excellence from mere competence. If Lexus is serious about its ‘Fuji’ moniker, it should fit a limited-slip differential and a gearbox better suited to fast driving. It has tuned the suspension to retain comfort while improving control, but in the end it excels at neither. And inside you’ll find seats that are too flat. Lexus has done well, but could do better.
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