In the S8 suspension option thread it noted the following:

From Audi, S8 as compared to A8: "A retuned, 20 millimetres (0.8 in) lowered sports suspension included a 30% stiffer spring rate and 40% more compression damping in the shock absorbers."

Is the 0.8 inch lowered referencing the over all lowering of the car measured from the bottom of the car to the ground? What about the spacing between the top of the wheel well arch and the top of the tire? Below are (2) pictures one of a 1999 A8 and a 2001 S8. As you can see the A8 has a considerable wheel well gap (4-6 inches?) where as the S8 is much tighter (2-3 inches?). The picture illustrates that the lowered suspension of the S8 vs the A8 is much more than 0.8 inch.

I have a 1999 A8 and wanted the S8 lowered look so I had the struts and springs swapped out from a salvaged 2001 S8. The car did get slightly lowered but very minimally and definitely not as low as an S8. Are there additional components that need to also be swapped out to lower the car or is it all in the springs? I called into the Audi dealership about the difference between the A8 and S8 springs and the parts personnel said they were actually the same with the same part number. So now I'm confused? Was the S8 that much of a heavier car placing more weight on the front springs to lower it that much? Or was there a re-design/facelift on the front fenders from 1999 and 2000+

Thoughts?

 

First, your dealer is full of crap about the springs...there are about 30 different spring rates (and 2 basic heights...A8 & S8) between all models of A8 and S8, signified by the paint mark codes on the springs which indicate a specific part #.

On facelift (2000 on) A8's the actual compressed springs are 20mm taller than S8 springs...that is the only component that lowers the S8 by 20mm...fender gap and ground clearance.

Pre-facelift A8's sit noticeably higher than FL A8's, with much larger gap at the fenders.

I really don't know if other suspension parts are interchangeable from FL to PFL, to lower it further or if it would actually lower it.

 

The reason the PF is taller then the FL is because the uprights/knuckle are different, (the hub sits higher on the FL). I also suspect that the spring seat is higher on the S8 shocks than the bilsteins.

Here is what I did to fix the gap:
http://forums.quattroworld.com/a8/msgs/36807.phtml

Ola
TerminA8r

 

hey there, alot to do with the ride height is how u load the front suspension, if u loosen evry thing an retorque everything ie lower arms upper link arms, lower arm the "zero point" changes,must be on a flat surface, as all the bushes are preload, your car will sit lower......i work for audi nz

 

Don't understand what you're suggesting(?)

Correctly installed (factory & repair) and car level under it's full weight, there is no "pre-load" in any suspension bushing.

By the book (and logic), final torquing is always done on a level surface with the car's full weight on the suspension...this is to allow the car to set (bushings UN-loaded) at it's lowest natural point, stress-free, with a given set of springs, handle normally and allow the bushings to live a long life.

 

I may need to replace all the front upper and lower control arms. Before I do, I thought about swapping my 99 A8 front spindle/knuckle with a 2001 S8 spindle/knuckle. This should help lower the ride height. Question is, do I need to get 2001 A8/S8 control arms? Or will the 99 A8 control arms still fit?

 

As I remember, the lower rear arm is not interchangeable from pre-facelift to facelift knuckles (bearing housing), but I believe the other 3 are.

Also, the S8 has different knuckle than the same year FL A8...arms are interchangeable, but I don't believe the brake calipers are. I think this is the only thing different between the 2 knuckles(?)...Brembo brakes (S8) mount on the side of the knuckle and HP2 brakes (A8) mount on the rear of the knuckle.

 

And the D3 S8 Calipers are a direct bolt on to the D2 A8, but not the D2 S8! Go figure. I badly wanted the D3 brake setup, but couldn't justify swapping knuckles just to gain another 40mm of rotor diameter. Would've been sweet though.

 

The S8 spring will lower the height, not the spindle.