mishar

I have to disagree. Making bushings harder would transfer more force to the chassis and potentially cause some damage, but making them more durable, like better material, won't hurt anything.

dvs_dave

Disagree all you like. Appreciably more durable but no stiffer bushing material is a suspension engineer's holy grail. Those two material properties are at odds with one another so it'll always be a compromise. Durability vs stiffness vs NVH. They all play into it and the engineers have made their selections based on an awful lot more research, testing and previous model durability feedback than we've done from our armchairs.

And it's not as if other large heavy cars don't suffer from bushing wear in a similar manner. Both my Dad's w211 and w212 e-class's have had a healthy appetite for bushings no better than the A8. It's just that we tend to think it's a problem that only affects A8's as that's all we read about on the forums. Other Marques usually have similar issues, it's just we're generally not exposing ourselves to that information on a regular basis.

MP4.2+6.0

All I can add is I am trying the S8 bushings/arms that are somehow different in their composition, at least supposedly. In 40-50K I may have a further practical answer, if I know where car is by then. Also FWIW, when you play with the bushings and arms in place, you realize they actually do need--or at least seem designed--to move in all three dimensions, so pretty complicated.

aTOMic

What I don't fully understand is why the torsional force on the rubber is necessary? Why can't the bushings just pivot on the bolts? I thought the dampers/airsprings/tire flex were in charge of up-n-down changes?
I see why the rubber can be used as it is, but it seems there'd be a much better way.

MP4.2+6.0

A hunch is if you study the designs and arms, it provides negative camber in the direction of and during a turn. Or in common sense lingo, it helps the front wheels lean into the turn to plant the tire width better with the forces involved.

mishar

Yes, it can be better designed if A4 (cheap) bushings can't survive forces and 3D flexion. Just a bit bigger bushings would last just as long as bottom ones that carry much more forces and same flexion. No need for a magic wand. But German engineers are still to discover that.

dvs_dave

You should write to Audi's design department. Tell them what you know. I'm sure they'll be very thankful

MP4.2+6.0

I'll go w/ Misha here notionally. The design is from a late 90's A4, that then migrated to D2 A8. D3 and D2 are basically same except air ride strut in front, or at least same in turn as my C5 4.2 which was apparently a D2 copy when they stuffed the 4.2 in the A6. Trouble was, wheel and tire weight on an A4 of the era was like 40 pounds, and brake rotor maybe 15. Make it 45 ish on a D2 and 20 on the brake rotors. Then pork it up to 50-60 on a D3 for the wheels and take the brake rotors to 30-40 depending on motor, and oops. They switched from cast iron calipers to alloy ones, but then got the way heavy cast iron bracket to go with it. Even over the life of the D3, these various wheel and brake diameters were sized up, yet suspension components not revisited. Said bluntly, poor ongoing design and sustaining engineering management.

And BTW, pattern continues on D4. Yet more wheel pork. Across most all Audis these days. They did offset it a bit with the quasi two piece rotors up front on the D4 and other larger brake ones, which in turn cost like 3x the $ of the standard cast ones. Virtually no aftermarket ones either--as the higher volume SQ5 owners who got the parts bin brake specials from the A8 3.0T are starting to find out at like $500 a rotor.

In general, the D's need a serious weight reduction--500+ pounds these days, maybe more. Run away HP has cloaked it, but they have gotten really porky even with our aluminum bodies. The suspension bushings are sort of the canary in the coal mine signaling something.

Jack88

In 2001, the S8 weighed in at just over 4000lbs. Today's model weighs 600lbs more. MP4.2 is right, these things have pulled a full Oprah, compensating for the extra poundage with more power than ever.

JohnnyJ A6Q

Beautiful !!!