Seat Leon Cupra in Depth

Press Release

• Adapted suspension settings plus new weight-reducing materials

• New steering parameters

• Oversized front brakes

When it comes to transferring all of the new León CUPRA's mighty 240 horsepower to the road, the SEAT Agile Chassis proves to be the perfect partner. It is not merely a question of producing a fast and sporty drive – it is a question of doing so whilst offering optimum levels of safety, precision and control.

The Agile Chassis from SEAT boasts a wealth of inherent strengths, but it has now undergone a series of measures that allow the León CUPRA to be piloted as if it was moving along invisible rails, with a feline agility that is made all the more impressive by the fact that it is a front-wheel-drive car.

The most important advance that has been made is the use of aluminium in place of cast steel for the steering knuckles and the stamped wishbone panelling. As a result, the unsprung mass has been cut by 7.5 kg at the front axle. This modification to the suspension components is furthermore particularly beneficial for the axle's kinematics as it reduces the tendency to understeer. Compared with the rest of the León range, including the FR, the front stabiliser bar has been made smaller too, measuring 22.5 x 3 mm instead of 23.6 x 3.5 mm as it does on the other models. The upshot of all this is superior vehicle traction.

As for the rear running gear, the suspension incorporates an independent, four-arm multi-link axle, which enables the longitudinal dynamics (comfort) to be handled completely separately from the lateral dynamics (agility), producing a ride that is both comfortable and agile.

The sports suspension concept found in the new SEAT León CUPRA is underpinned by firm tuning combined with a system of springs and dampers that offer the ideal progressive characteristics required for maximum precision, both when powering along winding roads and when cruising down the motorway. This set-up is complemented by firmer silent blocks which swiftly transmit the suspension's support to the body, tyres with a narrower slip angle and new steering with a firmer feel, enabling the car to respond instantaneously to the driver's commands and giving the driver complete control over the vehicle at all times.

In addition to this, the ride height has been lowered by 14 mm compared with a basic León and 7 mm compared with a Sport-up or FR model, to heighten the sensation that the León CUPRA is "glued" to the road.

Improving on the exceptional

The chassis fitted in the previous generation of the León CUPRA achieved benchmark status in its segment by virtue of its sporty handling, agility and fast response to the driver's inputs. The new León CUPRA achieves the seemingly impossible by actually surpassing the dynamic readings for the old CUPRA R, which, incidentally, was the first ever model from SEAT to offer the Agile Chassis.

When developing the chassis for a vehicle with the performance credentials of the new CUPRA, it is the readings for sportiness and agility which are of the greatest interest to the engineers.

As far as the values for vehicle sportiness are concerned, they are characterised by two parameters: lateral acceleration and roll angle. These values are measured by means of the steady-state test. This consists of driving in a curve with a constant radius. The curve used has a radius of 100 metres and the vehicle gradually accelerates from 40 up to 100 km/h whilst following the line of this curve. The object of the test is for the vehicle to maintain the line of the curve as closely as possible. As soon as the speed is reached at which the vehicle is no longer able to follow the defined trajectory, the test is stopped. The test results show that the new León CUPRA is capable of driving nearly 5% faster than the CUPRA R before it veers off course, with a reduction in roll angle of over 18%. In other words, the new León CUPRA boasts a higher cornering speed and less body roll.

Step steer is the name given to the test for measuring the parameters which define vehicle agility. With the vehicle travelling at a constant speed of 100 km/h, the driver suddenly turns the steering wheel to an angle sharp enough for the vehicle's lateral acceleration to reach 0.4g. As the aim is to produce this level of lateral acceleration, the steering wheel will have to be turned to a specific angle when travelling at a constant speed to produce the 0.4g of acceleration.

In this case, steering response was shown to be almost 10% faster in the new León CUPRA than in the previous CUPRA R.

Brakes that are a match for anything

The brakes were another of the features that underwent major reworking for the León CUPRA. In view of the tough demands that a car with 240 hp under its bonnet could place on its brakes at any time, the engineers opted for amply-proportioned discs measuring 17" and 345 x 30 mm at the front and 16" and 286 x 12 mm at the rear.

Steering assistance par excellence

Naturally, drivers of the León CUPRA will also have the peace of mind offered by the latest-generation ABS with electronic braking force distribution. In addition to this, however, the León CUPRA also comes equipped with the ESP Electronic Stabilisation Program (which can be deactivated) including EBA Emergency Brake Assistance, TCS traction control plus an array of further functions to aid the driver. These include:

• Overboost, which increases brake pressure without any notable change in the force that the driver has to apply to the brake pedal, when the system temperature far exceeds normal operating temperatures.

• BSW, which cleans the brake discs regularly whenever the windscreen wipers are switched on.

• Driver Steering Recommendation, which helps to keep the vehicle on the correct course in critical handling situations.

The most noteworthy of these systems is Driver Steering Recommendation. When the ESP control unit detects that the vehicle has entered an unstable situation caused by oversteer, it transmits a signal instructing the steering system's electric motor to turn the steering wheel in the correct direction. The driver senses this as a recommendation, prompting him or her to turn the steering wheel in the recommended direction and stabilise the vehicle. When driving over a dry, asphalted road, the driver barely notices this steering prompt. The system proves most effective when driving along roads offering differing levels of grip on each side of the car, e.g. a surface that is dry on one side and wet on the other.