The Phoenix Architecture that will underpin the 93 is aptly named; indeed, it is so crucial to Saab’s recovery that the firm’s engineering guru, Kjell ac Bergström, has put his retirement on hold for two years to oversee the project into production.
Bergström, who has also worked at Volvo and Fiat-GM, rejoined General Motors-owned Saab in 2003.
He had already outlined his vision for how an independent version of the Swedish brand could work before it severed its ties with the American giant.
The Phoenix Architecture seems to fit in with Bergström’s plan, in which many future components — everything from base engines to door locks — will be bought ‘off the shelf’ from manufacturers who supply parts to other premium car makers.
This policy is a U-turn for Saab, which has often insisted on modifying even the smallest common part to reach its own specifications.
However, the flexible nature of the process means that engines can still be modified in house, and Saab will still be free to carry out its own crash safety tests and introduce its own styling and electronic architectures.
The set-up will also allow Saab to give the 93 complex suspension systems and four-wheel drive.
The essentials of the Phoenix Architecture
For the Phoenix architecture, Saab has a choice of existing suspension systems. It could use the standard-issue MacPherson strut fitted to base versions of the 9-5.
However, MacPherson struts have limitations. They allow more vibration and disturbances from the road through to the driver and are prone to allowing torque steer with powerful engines.
Their construction means that they are also more susceptible to distorting under hard cornering, which leads to much less precise steering response. Many within Saab are now arguing that the Phoenix platform should actually be fitted with the much more sophisticated HiPer Strut.
The name is derived from High Performance Strut. This front suspension set-up was designed by Saab engineers for General Motors’ Global Epsilon project.
According to the company, the advanced HiPer Strut offers driving benefits similar to those of a double wishbone layout. “The inclination, length and offset of the kingpin is reduced and the castor angle of the steering increased.
“The result: improved steering quality with a more ‘planted’ feel, as well as enhanced handling and braking characteristics.”
Base 9-5s use a four-link independent axle, designed by GM and also used on the Insignia. It’s regarded as a capable design, but Saab also has the option of the much more sophisticated linked H-arm set-up.
Linked H-Arm axle
The linked H-arm was also developed by Saab technicians and is available on both front-drive and all-wheel-drive cars. The company says because it has isolated subframe mountings (unlike the four-link axle), it gives even greater ride comfort, reduces vibration entering the cabin and improves roadholding.
All-wheel drive system
Saab’s XWD (Cross Wheel Drive) system is based around the familiar and quick-acting Haldex 4 clutch, which is mounted on the rear differential. Torque can be transferred front to rear depending on grip levels (using 20 sensors checking information 100 times a second).
The trick aspect is the limited-slip differential on the back axle. Dubbed the eLSD, it can distribute torque between the wheels, meaning the torque can be variably split between all four wheels, matching levels of available grip.