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Here is a continuing story from Till and Hirsch, this time it’s all about photos! =)

Update below – added some Info from Hirsch

Last week I gave some insight on the aim Hirsch Performance had in mind when developing the products for the 9-5. Now let’s take a look at the results…

Equipped with the latest prototypes the Hirsch engineers finally went to the wind tunnel to see what the aerodynamic tweaks would mean in numbers. The car they used had the Hirsch lowering kit fitted because it is designed to support aerodynamics, too. I have to admit that I was pretty impressed by what they managed to do with those rather subtle parts. The optimized airflow led to a cd value that dropped by almost five percent to 0,27 compared to the standard 9-5. The lift on the front axle declined by 70%, on the rear axle by 40%. This is extremely healthy if you like to travel fast because you have much better high speed stability.

While the manufacturers started production the test vehicle, equipped with all parts of the 9-5 Hirsch Performance, went to a photo studio to get some nice pics for the upcoming release. Though I know that good photos don’t come easy it’s still fascinating for me how much effort and time it takes to end up with three pics. Sometimes you even wonder why you show up with a complete car as they photograph some parts separately in the perfect light and then put them back together. Here’s a short making-of-photoshoot video that gives a nice glimpse of the car.

The 9-5 aerodynamics package was, like all Hirsch products, developed in close cooperation with Saab. The test day in the wind tunnel for example was attended by Håkan Danielsson from the Saab aerodynamics team to check the results and add his expertise. Sure it sometimes takes a bit longer to work this way but in my opinion the product is worth the wait.

On a personal note I have to admit that I just love that car. It’s still a 9-5 but looks sportier without loosing the understated looks. I have driven the car with the engine upgrade and the tweaked suspension and I’ve enjoyed the exhaust note on a test drive back in March. I’d have a hard time choosing which parts I’d take if I were to buy a 9-5. Most likely I’d take all of them.

As Rune had some specific questions I dug out a bit additional info (thanks to Erik Lundgren from Hirsch):

On the rear spoiler used individually:
“All bits improve stability and lower drag even when used individually. However, when it comes to lift, it is more a question of balance and which configuration you compare with. Adding a rear spoiler reduces lift in the rear but increases it slightly in the front, and the front spoiler reduces lift in the front but increases it slightly in the rear. What we have done is we have made the parts so that they can be used separately without causing critical lift on the other end of the car. To get optimal stability and lift reduction, the complete kit should be installed, together with the sports suspension.”

Front ground clearance/approach angle:
If you look closely, the front spoiler bottom surface extends only one cm downwards, but extends maybe 5 cm forward, which means that the approach angle is hardly affected, yet the front stagnation point for the airflow is significantly lowered.”

And an additional comment on the cd value:
“Since the wind tunnel used doesn’t have a moving ground, the Cd values we measured both in standard configuration and with the aerodynamics bits and pieces were all about 5% higher than in a modern wind tunnel. Normally, the car would have 0,27 already standard, and we would improve 5% on that.”