Stoney

Yesterday, bdog4.2 and I switched cars for a short drive.

Bottom line conclusion: H-Sport sway bars are a great mod in value terms, but there are some important things lacking if you don't also upgrade the springs (and shocks). Subjectively, the 2002 with stiffer springs felt more sporty than the 2001 with sway bars.

The cars:

His: <A HREF="http://pictureposter.audiworld.com/users/46141.phtml">2002 A6 4.2</A> (the year improvements were made to suspension) with <A HREF="https://forums.audiworld.com/a6/msgs/307696.phtml">H&amp;R sport springs and stock shocks</A>. Also, chipped engine and transmission, aftermarket exhaust, <a href="https://forums.audiworld.com/a6/msgs/307441.phtml">Oettinger RZ 19's, and Stoptech brakes</a>.

Mine: <a href="http://sonolithics.com/pics/audi_a6_42/index.html">2001 A6 4.2</a> with stock shocks/springs and H-Sport sway bars set to firm.

Comparisons:

My car with sway bars only: My car handles a bit more level than his 2002 with H&amp;R springs. Less roll, and perhaps just a bit more sense of sharp turn-in and stability in the yaw direction (left-right floatiness of the body relative to the wheels), as LMGotts has written about many times regarding the stock 4.2. Even though bdog4.2's springs were stiffer than mine, I felt a slight roll in his car, perhaps a bit more than mine.

But, my car has more squat on acceleration and dive on braking. The sway bars don't do anything for these. Also, his car handles rather level on absolute terms anyway. If I had to pick one, I'd pick his suspension.

Also, in my car, a slight sideways bobble is felt that makes the car feel a bit narrower than it really is. The bars help the car feel lighter and more stable, no doubt. But, it isn't as "planted" as it could be, subjectively.

Here is what I think is happening: As uneven pavement occurs, which previously would have been absorbed by one wheel's suspension or the other, now that is transmitted a bit more to the passenger compartment. This means that the car bobbles side to side a bit. The amplitude is less than before the bar upgrade, but its frequency is higher, so it is a bit more noticeable. My wife says "it feels less luxurious." However, none of us thought it harsh, just less smooth.

This sidways oscillation is slightly underdamped, given the stock shocks. Consider it this way: we have stiffened the spring that keeps the body level with respect to wheels. The restoring force for motions of the body tilting left or right has been stiffened... but the damping has not (similar to how stiffer springs with stock shocks can cause a vertical bounciness at a higher frequency). So, the car can oscillate slightly from side to side about the flat position (before being damped out), and this oscillation is at a higher frequency than before the H-Sport bars.

For this reason, I suggest that the suspension is not quite "finished" with just a sway bar upgrade. I think a stiffer spring and shock is needed to complement them. (I don't plan on upgrading in the near future, but eventually I will get coilovers to round out the suspension upgrade).

The swaybars do help prevent large lateral oscillations in many situations, such as around the corner near our house around 15-20 mph... previously, the car would buck and bounce over the rain gutters. This was very uncomfortable for passengers. Now, it hardly responds. Of course, there would be virtually no benefit if I went over the gutters straight-on.

I also feel far more confident and steady at high speeds, straight or curved, now that the bars are installed. Less drama on the highway. But, again, sway bars can't cure all the floatiness, such as the roller-coaster feeling over the sagging elevated highway 280 dogleg near Pac-Bell Park in San Francisco. I haven't driven it yet with the new bars, but I'd be surprised if they reduce the up-down float significantly.

Bdog4.2's car felt wider and more planted. It also is lower, and feels it. I wonder if perhaps his car might respond better than mine at high speed over road irregularities or in evasive maneuvering. That is where the stiffer suspension would help keep the wheels on the road.

In summary, the upgrade of sway bars, springs, and/or shocks each have their own benefits. You can't get well-tuned suspension by just upgrading one or two. On a value basis, I'd say get bars, then springs, then (or simultaneously) shocks.

I'd say that, in performance terms, if I had to pick either sway bars or coilovers, I'd pick the latter. However, only a value basis, the sway bars come first. And, ideally, one gets both.

Brakes: The Stoptechs make the brakes a lot firmer and they bite strongly early in the travel. I'd like to have tried it in traffic at creeping speeds to see the benefits in terms of modulation.

Still, I didn't feel like my brakes were misbehaving or substandard, upon swapping cars back. The stock brakes feel reliable enough for the occasional very aggresive driving (non-track). I'd consider the Stoptechs, or at least some rotors and pads, before tracking this car.

FWIW

richmond5

Very interesting and informative comparsion!I knew you got sport pkg on yours, does bdog4.2 has sport pkg? I notice too, with H&amp;R the car is much lower than yours which is already lowered than non-sport pkg.

Gerry

to reduce the independence of the independent suspension. The same forces that reduce roll by opposing the compression of a single wheel, also by definition, reduce the compliance of that individual wheel over smaller, one wheel irregularities. Its interesting to note that Audi took the opposite path as they went from the 4.2 to the S6. They stiffened the springs and struts and left the sway bars as is. Possibly, that makes the S6 a better candidate for a sway bar only upgrade.

Of course another contributer, as you mention, would also be the balance of all the components in working together.

Cargasm2.7

Keep in mind that his 19's with fat rubber effect feeling quite a bit.

AUJ

angle. Low profile can be taken to far on this platform, IMHO.

Sleestack

4.2 with stock sway bars and H&amp;R coilovers, contact me. Also chipped with GIAC engine and tip chips.

Stoney

I suspect we'd both enjoy a test drive. Bdog4.2 is close to a purchase of coilovers.

Stoney

You might want to remove your email before Google gets a hold of it.

ChesterY

"the roller-coaster feeling over the sagging elevated highway 280 dogleg near Pac-Bell Park in San Francisco"

Amen to that. I've always wondered what that section would be like with some good, stiff shocks/springs.

im_cecil

I suspect you're right about the minimal benefits to straight-on irregularities. I know the 280 rollercoaster very well and it will be interesting to hear what you find. Interesting comments about the side-to-side amplitude vs. frequency bobble, too... makes sense.

As for value and order of upgrade, there's another option that I don't see anyone talking about... upgrading the struts alone, while maintaining the stock (sport) springs. I think that's the way I'm likely to go.

I'm not particularly interested in lowering the car much (any?) more than what came with the PSK package, nor creating a jarring ride. Been there several times in the past. I'm pretty happy with the ride comfort and overall clearance, but wanted it flatter in the corners, which is why I bought the H-Sports.

So, when the OEM struts go out, I will likely upgrade to a slightly firmer and higher quality replacement, a la Bilstein. I think this will still be a good match for the springs.

I would not do springs alone without struts, though, as I think the rebound rates of the available performance springs are relatively more dramatically different than the originals, and thus need suitable damping. Nor would I get higher-performance struts without the sport package springs.

FWIW.