PaulW

Luiz, our friend from Brazil said he ordered a rear sway bar for his pre facelift S8....and it's 28mm, his original is 20mm.

Here's the info....I'll have to call Audi sometime to see if this is true:

Paul,
The rear sway bar is an original Audi item.
Here are the parts numbers:
4DO511409L - the rubbers
4DO511327F - the sway bar
4DO505465D - the connecting rods
My front end sway bar is 29mm, like yours.
Luiz

------------

He actually just called me on the phone, we spoke, he says they call him the "grave robber" because his S8 is black and is beating everything in San Palo Brazil!

You got to love it!

pw

PaulW

Even though it's listed above as the bushings, it's actually the bar.

There is one for an armoured car:

)
4D0 511 409 J
STABILIZER
FOR ARMOURED VEHICLE REAR<ul><li><a href="http://www.elcats.ru/audivw/vag5.asp?subm=%CF%EE%E8%F1%EA&amp;btsnr=501-20&amp;cid=153">Does this link work?</a></li></ul>

banal

so my 01 a8l is a 20mm bar? what exactly would swapping it to a 28mm bar accomplish?

Luiz Goncalves

Installing a thicker sway bar in the rear will improuve stability,however, the understeer tendency will increse. Undesrteer tendecy is easier to correct than oversteer tendency

ryoung

4DO 511 409 J - the 28mm rear bar
4DO 505 465 D - the connecting links
4DO 511 327 C - bushings for 20mm sway bar (S8 suspension)
4DO 511 327 F - bushings for 17.3mm sway bar (self-leveling suspension)

What bushings do we use with the 28mm bar? None are listed for the armored car ... just get new 20mm bushings and make 'em fit?

Do you recommend installing new connecting links?

ryoung

The 20mm bar is used on the S8. A stiffer 28mm rear bar would reduce understeer.

gamma500

............or increase oversteer..... I have stiffened up the rearend on quite a few understeer-prone vehicles with good results but, be aware, when pushing her hard or surprising yourself in an unfamiliar decreasing radius turn, your car(as Ryan knows)may try to swap ends. Unlike understeer where any degree of throttle chop will bring the nose in (no tail out here, just the front pushing) and get you back happy pretty easily, a significant understeer resents anything but the exactly called for throttle decrease following by throttle application or you will complete your 180 degree pirouette or tail wag left and than right until you have soiled your britches. My point here..if you drive aggressively enough to get the tail loose on corners, than go add the stiffer rear sway and maybe have the rear tires a few pounds low, you might experience that same corner in a whole new light the first time you retry it. Get a feel for the new handling characteristics and decide if you really want to modify and risk the above occurring in some situation where, even driving fairly sedately, some unforseen patch of wet leaves, ice, etc. shows you what new things the rear half of your A8 is capable of. Of course, you can mitigate the oversteer situation by a full suspension retune and corner balancing to acheive a more neutral cornering with a touch of understeer at "all out", my preference, on the street, or a bit of a loose tail for the track.

Regards,

Craig


Craig

KaMaKaZieP -ALUMIN8-

Randy, we talked about how the 20mm bar will potentially cause the car to have less grip in the rear on a hard turn.. will this 28mm bar increase that more? Is this a good idea with stock suspension?

skiracer

this would be great for the A8 as long as it doesn't shift it too far towards oversteer. Or am I smoking??????

ryoung

A stiffer rear bar results in less grip in the rear AND more grip in the front.

A stiffer rear bar increase the difference in load distribution across the rear tires, which reduces total rear tire grip. At any point in a corner, though, the total left-right and front-rear load distribution on the tires is fixed. If the load distribution across the rear tires increases, the load distribution across the front tires decreases; and as a result, the front tires have more grip.

I assume that an "armored A8" has stiffer bars in both front and rear. Body roll is reduced while still maintaining the original handling balance.

Will a 28mm rear bar be too much for a stock A8 suspension (or even an S8 or H&amp;R suspension) and result in unacceptable oversteer? Will the 28mm bar result in lifting an inside rear tire (not good with even an AWD car) during hard cornering? Unknown to both questions. There's only one way to find out, but I'd be willing to try :-)