Development

Engine testing at Hirsch Performance

In the sound-proof and bullet-proof test cell at Hirsch Performance, the Saab engines are taken to their extremes. The worst possible ambient conditions are simulated by regulating temperature and pressure of intake air to simulate desert heat or high altitude alpine passes. Computer-controlled water and charge air cooling systems are used to simulate poor cooling as enocuntered for example in traffic jams at high temperatures. During these extreme tests, the engines are closely monitored to ensure that no critical components such as cylinder head, catalyst or turbocharger become overheated, overstressed, or overspeeded, while keeping a close eye on emission levels so that they are not exceeded.

But it is not enough that an engine performs well under controlled conditions. All Hirsch performance upgrades are therefore test driven on the German Autobahn at steady state at top speed to ensure that the performance is really there when it matters, and that the integration in the car works as it should.

Then, to validate the durability, the upgraded engines are driven at full load at various RPMs according to a predefined test cycle. The durability test runs at full throttle around the clock for a month, stopping only to change oil at the regular service intervals. Thereafter, the engines are dismantled to check for fatigue, wear and other damage. So, as an owner of a Hirsch Performance Saab, you can rest assured that your engine has the durability it takes.

Meanwhile, the upgrades are driven by several test drivers to ensure that the driving experience, the torque curves and pedal response feel just right. Because in the end, a performance upgrade from Hirsch Performance is more than just added horsepower.

A Hirsch Performance upgrade is built for a reason – to give you the ultimate Saab driving experience.

Aerodynamics

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.