360 Modena - Cars - http://maxpages.com/pcars/360

The 360 Modena features a classic Ferrari spaceframe chassis design. However, the structural frame members are made of extruded aluminium connected by castings where the members join. These castings allow for expansion during assembly, and also provide extra strengthening in areas subject to the greatest stress.

The project introduces a large number of manufacturing and assembly technologies which were designed specifically with the American Alcoa company for the chassis components. The technologies developed range from the extrusion process, bending, top quality sand and vacuum casting to the riveting system and Mig welding.

The suspension mounting points on the chassis - a parameter that is fundamental for the car’s handling - are obtained on a single casting and machined on the assembled spaceframe.

This technology, already successfully introduced on the F50, allows minimum tolerances, typical of a precision mechanical part.

The specific weight of aluminium is one third that of steel, and the weight of the overall chassis was cut by 28%, in spite of a 10% increase in volume while boosting rigidity by 40%.

The engineering process, backed up by the most advanced computer simulations, led to the design of a chassis which, although lighter, meets all passive safety requirements envisaged by world legislation.

The 360 Modena brilliantly passed all reliability tests on the test bench, on the road and on welded sub-assemblies. In particular the effort of the complete standard chassis at the bench has been measured at the limit road condition of the car, forcing the car to an acceleration value of 1.2 g.

It is also far more resistant to corrosion than normal steel structures.

Welders were certified with recognised bodies as qualified to carry out structural welds for both manufacturing and repairs to the new frame.

The technical parameters that would respond to the objectives of improved handling, active safety and driving enjoyment were defined right at the briefing stage.

The wheelbase and the front track, respectively, 150 mm longer and 155 mm wider than on the F355, in addition to increasing cabin space, also increased stability and improved tyre wear.

A double wishbone layout for the suspension was adopted front and rear with full kinematic properties and with anti-dive and anti-squat geometry.

The rear suspension includes a suspension arm between the hub flange and the chassis frame known as 'false steer' which keeps the suspension arms isostatic and allows rapid adjustment to toe-in.

The same aluminium hub-carrier is used for the front right and rear left wheel; the upper and lower wishbones are in aluminium, and the rear anti-roll bar is made up of two sections and is housed inside the profiled frame cross member.

The innovative damping system developed with Sachs marks a significant step forward compared to other existing solutions, and has its roots in the active suspension project of the early 1990s. The four aluminium dampers incorporate a complex patented solenoid, with three acceleration sensors and a control unit which also picks up car speed and braking signals from the onboard sensors.

A switch on the dashboard offers a choice between two driving programmes, Sport, and Normal for enhanced comfort.

The control logic envisages the use of six 3-D maps based on combinations of the various signals measured instantly by the sensors.

The high number of parameters and practically instantaneous intervention on calibration curves make it possible to 'brake' body movement immediately and to maintain the best wheel-road contact, increasing grip and stability.

At the wheel, the car feels very smooth, with rolling and pitching kept to a minimum, and extraordinary turn-in accuracy onto the desired line.

The steering is equipped with a non-speed-sensitive servo, and a pump with two flow levels, depending on the engine speed.

There’s a very direct steering ratio of 60 mm per turn, enhancing promptness, precision and driving enjoyment.

The turning circle is just 10.8 m, compared to 12 m on the F355, for better low speed manoeuvring.

Wheels and tyres have been adopted with the goals of reducing aquaplaning effect and steering effort; the results of the computer simulations prompted the adoption of smaller front tyres (215/45 ZR18) and larger rear tyres (275/40 ZR18) mounted on 7.5" and 10" wheels respectively.

The development tests carried out with Bridgestone, Michelin, Pirelli and Goodyear, confirmed that the initial choice offered advantages in terms of handling, grip, aquaplaning and uniform wear. The alloy wheels weigh about 1 kg less than the magnesium wheels of the F355, thanks to stylistic optimisation and the new channel technology.

Brakes are with large diameter vented and cross-drilled discs (330 mm) and are fitted front and rear, with four-pot (38 -- 42) aluminium calipers; the brake servo offers lower pedal effort to provide greater promptness.

The bigger discs also made it possible to maintain a lower thermal load, improving resistance to fading without forced cooling.

The emphasis was on braking stability rather than braking distances, but these too were improved, particularly at high speed.

On 360 Modena for the first time Ferrari used the combined Bosch 5.3 ABS/ASR system with EBD brake effort correction and MSR anti-lock deceleration on a mid-engined GT car.

Starting with the positive experience gained with the 550 Maranello, it was decided to maintain the choice of three operating modes -- Normal, Sport and Off -- for the ASR system.

In the Normal position, the system acts on the brakes of the drive wheels and the engine torque, both on the straight and when cornering, to enhance stability.

In the Sport position, higher wheel spin thresholds are adopted, retaining control over the engine and brakes on bends, and only over the brakes on the straight to enhance traction and a sporty driving style.

The use of the drive-by-wire system guarantees smoother engine response when the ASR cuts engine power and feeds it back in, improving comfort. The Drive-by-Wire throttle also makes the MSR function more efficient, guaranteeing vehicle stability on lift-off and when shifting down in conditions where there is poor surface grip.

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Page Updated Wed Aug 9, 2000 4:02pm EDT