Lexus IS F 

F – SETTING NEW STANDARDS

Why F? Fuji Speedway and Higashi Fuji Technical Centre at the foot of Mt. Fuji have been home to the develop-ment of the IS F. That’s three good reasons. Perhaps a better one is ‘finesse’. Like every Lexus, the IS F has to conform to what are probably the most stringent standards in the motor industry, those of Lexus engineers and designers, before it was even considered for public consumption.

To these dedicated individuals the challenge was to build a mould-breaking performance car whilst embracing the traditional Lexus values of technological sophistication, advanced safety, leading-edge engineering and unparalleled refinement. To take another step forward in Lexus’continuous pursuit of perfection.

INNOVATING F PERFORMANCE

The challenge of creating the IS F lay in increasing the “Instantaneous Sensory” elements of driving. To combine core Lexus elements with the ultimate in braking, acceleration and handling performance to form a unique drivers car, a genuine all-round high performance car, equally at home on track days or weekend trips. 

In doing this the IS F engineering team needed to redefine how the driver feels about, and responds to his car. The IS F chief engineer wanted to deliver an unbroken series of sublime moments for every driver, resulting in a unique per-formance experience, one that totally redefines motoring at every level of  driving skill. No easy proposition.

MILLISECOND RESPONSIVENESS

Achieving the IS F chief engineer’s ideals meant the develop-ment team rethinking every element of conventional performance. They wanted a car that would arouse any driver’s emotions, one that could “talk” to the driver, yet still deliver all the finesse that people expect from Lexus. For dynamic refined power they chose a compact 5-litre V8 engine. 

By combining this with the world’s fastest 8-speed Direct Sport Shift (DSS) trans-mission that shifts gear in just 0.1 seconds, they delivered the kind of direct response  formerly only found in the upper regions of motor sport.

To contain this power, braking and suspension techniques were taken from the racetrack and refined for everyday use. Finally they added a new type of VDIM (Vehicle Dynamic Integrated Management system), before letting loose some of the world’s best test and racing drivers to finalise the mix.

SOUND CHARACTER

A civilised yet extremely powerful engine, one that delivers smooth urban driving yet fun circuit driving, has never been easy to achieve. With the IS F the choice of an  extremely compact 5-litre V8 was the first step towards realising it.

The IS F engineering team soon decided that one of the prerequisites was a to use a dualintake system, one which controlled both the inlet length and the number of available inlet ports. This allows both the amount and quality of the mixture to be much more efficiently controlled and lays the foundations for both the gentle  and powerful aspects of the IS F engine.

The optimisation and harmonisation of Lexus D-4S* direct fuel injection system with the VVT-iE** variable valve timing system also received detailed attention. This not only delivers optimum power/torque combinations, but is also of primary importance in achieving the ultra low levels of emissions that have become expected of Lexus.

Critical driving perception rests on split second impressions, so to increase the sense of unity between the accelerator and engine, newly designed high flow intake ports and a small capacity surge tank were adopted to improve efficiency. 

To maintain engine stability during rigorous circuit driving, a newly developed head-scavenge oil pump and oil cooler were adopted. As a result, optimum lubri-cation and oil condition is main-tained even during high G-forces and high operating temperatures. All of these measures play a major part, not only in the immediacy of the engine response, but in the seemingly endless linear acceleration available.

Another emotive area, the actual sound of the engine, received high priority with the IS F. The car’s highly significant aural sound design falls into three distinct categories. In the low and medium speed range, the V8 engine creates a strong exhaust sound, while maintaining overall tranquility. When the higher speeds are reached, the second intake port opens, and the engine sound changes suddenly to an impressively powerful sound. 

As the engine approaches the maximum speed range, only the polished and pure mechanical sound of the engine can be heard, intensifying in synchronisation with the engine speed.

*D-4S is Direct Injection 4-Stroke Superior

** VVT-iE is Variable Valve Timing – intelligent Electric (on intake)

HEART AND RATIO

A special kind of power demands a special type of transmission. The IS F introduces the world’s first and fastest, production 8-speed Direct Sport Shift (DSS) gearbox.

The new 8-speed DSS transmission of the IS F offers all the benefits of manual gearshifting, but with full automatic convenience. A revolutionary lock up mechanism allows the engine’s power to be directly relayed to the transmission in second through eighth gear, giving it the ability to up-shift gears in just 0.1 seconds. That is faster than both dual-clutch and sequential manual gearbox technologies. It also results in an immediate and direct shift feeling. 

With so much power to transmit, easy starting and shock-free changing were high on the list of priorities. The lock up clutch mechanism helps facilitate both. Also a new oil cooler and catch tank keeps the oil temperature and pressure optimal, even during intense circuit driving.

And naturally there is a “skip-shift control”, a manual override, available whenever the car is in drive. This allows the driver to fingertip select any ratio, adding the dimension of full manual control. All of this adds up to technology that pleases on the track or just takes care of those endless traffic days with equal efficiency and satisfaction.

ADAPTIVE CONTROL

With the IS F the Lexus engineering team created a car that redefines Lexus in terms of sporting handling, while still retaining the virtues that Lexus customers expect. The coil and wishbone front suspension and multilink rear, coupled with electronically controlled power steering provided the perfect basis.

To refine the suspension IS F engineers used a data gathering system more usually associated with racing saloons to analyse the suspension behavior under every condition. This led them to re-evaluate every aspect, even the bushings. The result is a suspension system that fully complements the dynamic performance of the car.

Once this was in place they began work on a new Sports VDIM (Vehicle Dynamics Integrated Management) system. This controls every dynamic aspect of the car and again the IS F development team tested this under every conceivable performance situation. The difference versus the acclaimed VDIM on other Lexus models is that on the IS F it now features a Sports mode to stretch its dynamic capabilities even further. For the most experienced drivers, it can even be switched off completely.

DRIVING CONFIDENCE

Having attained maximum driver satis-fac-tion from the steering and suspen-sion would amount to nothing in creating ultimate driver confidence without re-evaluating the brakes. For this, 360mm ventilated and drilled, 6-piston front brakes and 345 mm 2-piston rear brakes were jointly developed together with Brembo. These deliver optimum braking performance and respond perfectly to mercilessly repeated demand under even the worst conditions.

Forged, sculptured 19-inch alloy wheels developed jointly with BBS reduce unsprung weight to near full-race efficiency. Together with ultra-low profile tires developed with both Bridgestone and

Michelin they were essential in delivering the increased grip and flexibility, together with the special smooth road manners of the IS F.

In fact working together with the advanced sport VDIM, the brakes, tires and wheels were largely instrumental in the fact that Lexus test drivers could lap the Fuji Motor Speedway faster with the VDIM in Sport mode than with the VDIM switched off. Clear evidence that in Sport mode the VDIM works with, rather than against, the skills of the driver to create real confidence.

F-FORWARD

The Lexus IS F is a performance car that travels from 0-100 km/h in under 4.9 seconds*, maintaining linear acceleration to its governed maximum of 270 km/h. Yet it does that without permanent damage to the eardrums or seating access designed only for contortionists.

Dynamically, the IS F provides high safety standards without being obtrusively safe. The car has been tested by world class racing professionals, who have helped refine every aspect of the VDIM system, chassis and steering.

Above all the IS F is a Lexus. That means every aspect has superior quality and integrity designed and engineered in. It is a unique performance car, but it is also a true drivers car. 

* Preliminary specifications

Yves SCHAMP – 2007