Hirsch Aerodynamics for the Saab 9-3
Dec 26, 2008 - 11:26:01 AM
source: Hirsch-Performance

New for the Saab 9-3, Hirsch Performance have developed a complete aerodynamics package.

Improving the aerodynamics of the current Saab 9-3 was a real challenge, since the car has excellent aerodynamics already from factory.

However, for this project Hirsch Performance enjoyed the co-operation and support of Saab's master aerodynamicist HÃ¥kan Danielsson and his team, as well as renowned designer Taras Czornyj from Mutations AB, whose combined experience made it possible to develop a truly exciting aerodynamics package.

The final product range reaches from front splitter to an exclusive - limited edition - carbon fiber body kit for the SAAB 9-3 Performance special edition car.

Form follows function - the design process
The aerodynamics package was designed as a complete set of modifications to improve stability and reduce drag. In addition to the functional benefits, the aerodynamic modifications should also contribute to the car's dynamic appearance.

During the entire development process, close co-operation between design, aerodynamics and engineering ensure that the end result creates the best possible experience, both when viewing the car from the outside and when driving at high speeds.

The design process started with the sketching phase, trying to get the most distinctive look possible while still integrating with the shape of the original car.

The sketches were then interpreted in clay, to ensure that the shape of each component looks good from all angles.

Once the basic clay design had been approved, the car was scanned using a 3D-Scanner, and the surfaces translated into 3D computer models.

Aerodynamic Optimization
Based on the computer models, aerodynamic test parts were produced and specially prepared so that minor adjustments could be made quickly during the wind tunnel testing.

Front splitters were added to reduce air flow under the car and in front of the wheels, thus creating down force.

A larger front spoiler was integrated with the lower mesh grille, further reducing air flow under the car while also increasing the cooling air flow for the intercooler.

Side skirts were added to reduce wake behind the wheels and keep the air flow under the car from leaking out.

In the rear, a diffuser was added under the bumper to direct the air flow slightly upwards, thus reducing the wake behind the car while also improving rear stability.

For the Convertible and SportSedan, enlarged bootlid spoilers also help improve rear stability.

The perhaps most interesting component, however, is the roof spoiler for the SportCombi, where a Saab innovation from 1961 was put to use again in a modernised form: the air slicer. The top surface of the air-slicing roof spoiler directs the airflow upwards, generating improved rear stability. In addition, an air slot directs a small portion of the airflow down onto the rear screen, thus reversing the semi-stationary vortex behind the car and thereby reducing the wake and the associated aerodynamic drag, while also helping to keep the rear screen clean.

This design was extensively tweaked and tested in the MIRA wind tunnel, to create an optimal combination of drag and stability.

Safety First
Once both the design and aerodynamics targets were met, homologation prototypes were produced. All prototypes were installed on cars and sent to RDW in the Netherlands for homologation. At RDW, the parts were examined to verify that they will not influence the safety of the car or the safety of pedestrians in case of a collision.

All aerodynamic parts have successfully passed the homologation tests, and are included in the latest Saab 9-3 whole vehicle type approval, and can therefore be installed in all markets.

Hirsch-Performance Website
TurboNines Hirsch Performance 9-3 Sedan Photo Gallery - with exclusive mockups of various car and wheel color choices.