|August 10, 2005
Project Audi B6 A4: Suspension / Handling
What is it about Audi's stock North American suspension offering (both non-sport and sport versions) that drives enthusiasts crazy? Undoubtedly it has to be the pliant nature of the ride which is based, in large part, on the notion that North Americans want to be cushioned as they mindlessly cruise the local interstate highway.
This suspension issue is certainly not unique to Audi - many manufacturers dial in different settings on this side of the pond - but it is nevertheless an ongoing issue for performance-minded Audi owners. Granted we have no pristine Autobahn or Autostrada where a stiffer suspension would be more than welcome, but that doesn't mean that the suspensions that are offered are acceptable to perfect.
Audi's stock suspension will err on the side of understeer when pushed hard. This is probably a good thing from a safety perspective since it reduces the risk of putting the car into a 360-degree spin. Our goal with this project series, though, is to create a car with more neutral handing or even a slight oversteer tendency. Oversteer, of course, describes a situation where the rear end of the car is looser than the front end so that (in the hands of a capable driver) the car is allowed to rotate or turn better while cornering on a track or autocross course.
To be fair to Audi, we know based on extensive discussions with their executives that suspension design and engineering an area in which considerable time and energy is devoted. In a memorable conversation with a Board Member a couple years back we were candidly informed that building "a very firm, race-ready suspension is easy actually quite easy." What Audi sees as an enormous challenge and therefore takes a great deal of pride in developing is, in the words of this same individual, "a suspension that retains supple ride characteristics while concurrently taking on an advanced level of high performance proficiency."
Even if it is an engineering feat, the A4's suspension still has some of the qualities previously described which keep it from being called truly high performance. With that in mind we set out to address the issue via one of the height-adjustable coilover kits currently available in the market. In our opinion having a fully height-adjustable suspension is highly desirable because it allows the owner - on a day-by-day, situation-by-situation basis - to decide exactly how high or low the car sits. We knew we wanted something fully adjustable, not a kit providing just a couple of different spring perches.
Another important consideration would be dampening adjustability. Some aftermarket suspensions actually have to be removed from the vehicle in order to adjust dampening, and many have no dampening adjustment at all. We wanted the flexibility to make dampening adjustments on the go.
Choices to Make
We looked first at high end - high both in terms of performance characteristics and price. This led us to the StaSIS Motorsport kit with external reservoirs, as well as their Tracksport kit. Without any cost limitations we could have very well pulled the trigger on one of these excellent setups, but in the end we determined that we didn't actually require it based on goals for this project car.
H&R Special Springs coilover kit was given a look but was then eliminated due to their lack of dampening adjustability. Kits from KW, Tein and a few other suspension companies were also evaluated but not chosen because they either did not offer a coilover application for the B6 A4 or because they were not being widely used in the marketplace.
Eventually we discovered Bilstein's adjustable kit for the B6 A4 which met all of our requirements. Arrangements were made with Griffin Motorwerkes in Berkeley, CA to pick up a set of the PSS9 coilovers directly from Neuspeed. The kit arrived in a box as big as a man! We were surprised by the sheer size of the damper in the front, which were much larger in diameter than the Bilstein dampers found in previous versions of H&R coilovers. Right on the side of each damper we were pleased to find the adjustment dial - in a spot where it could be easily reached after installation.
Page: