On other cars I've had upgrading the swaybars was always a relatively easy and low cost option for upgrading the handling.
Why is this not discussed as an option on the A4?
Mark
'00 A4 1.8T QMS<p>Mark
'00 A4 1.8T QMS

 

Really, I have to say this. l hope that rather than sounding like a flame, you will read this through and see if maybe I have a point.

When many (dare I generalize?) if the people on this list talk of improving handling, the first thing they talk about is lowering the car and putting stiff springs on it.

Why don't you want a car to roll? Because the tires like having their entire contact patch of the loaded tire (those on the outside of the turn) parallel to the ground with as little carcas distortion as possible. Suspensions can be dialed in so that the tire remains flat to the ground through a limited range of motion. As the car rolls, it might exceed this optimal condition and thus you won't get maximum grip.

There are advantages to lowering a car. It lowers the center of gravity, and that helps reduce body roll in a corner. All this is well known. However, this is where the discussion seems to stop.

The current mania for stiff springs can be traced directly to the rise of ground effects in racing. In the old days cars lifted at speed, your steering got light, and all was wrong with the world. In the '60s people began experimenting with wings and airdams to keep the car from lifting. In the '70s, starting with Tyrell and Lotus, ground effects as we know them today (discounting Clarks Chapparal 2J sucker car) came into being. It became possible, for instance, for a Porsche 962 to develop 10,000 lbs of downforce on the Mulsanne at LeMans. This very high downforce number necessitated stiff springs to keep the chassis from scraping the ground at speed.

Now back to an A4. Noones A4 develops downforce! There I said it. We can try tricks to reduce lift at speed, but we will never develop downforce with our cars, unless you get a serious wing (no, I don't mean a spioler), a full smooth belly pan across the bottom, pitch the nose way down, and reduce the ride height to < 3". Since noone in the registry's car looks like this, I can safely make that statement.

Using stiff springs to counteract roll falls into the old racer adage of "any suspension will work great, if you don't let it!" Stiff springs deny you compliance over bumps and can lead to a very twitchy car.

Antiroll bars are on the car for a reason. As the car rolls, the force trying to roll the car (a slow and gradual force on the order of 1 Hz or less) rolls the car to the outside of the turn because the center of gravity or almost all cars is above its roll center*. The anti roll bar takes some of this force and does two things with it: absorbs some as torsion by twisting, and transfers some of the force to the other wheel, compressing the opposite spring and lowering the entire chassis. A stiffer antiroll bar will twist less, so it does more work on the opposite wheel.

Springs and shocks are designed to absorb the impact of hitting irregularities on the road. These events are in the 1s to 10s of Hz. So changing your dampers
will not affect your roll rate. It will affect your compliance and the way a car handles bumps. An overdamped car is just as bad as an under damped one.

What I see happening is a lot of drivers (this is far from uniquely Audi) see low race cars with huge wheels and low profile tires ripping around the track at high speeds. They think "this must be the answer!" and go out and try to make their cars look the same.

What you can easily end up with is a stiffly sprung buckboard with lousy ride quality and bent rims from pot holes.

Lets get real here. How many of us race our Audis? Really. How many of us have ever won money from it, or have been offered a ride for a team based on how trick our A4s are? Track days should be fun and educational, but if you are serious about racing, might I suggest getting a race car?

What works on the race track is not the best for the street. My 99.5 with sport package already scrapes the ground too often for my taste. What good is it to have a "super fast racing suspension" when you have to baby it along at 10 mph so you don't drag your belly on the pavement?

So, if you want to counter body roll, get bigger bars. Lowering the car will help, but the limit is how low can you go to get that BTCC/DTM/SuperTouring/whatever look and not rip ieces off your belly.

Don't misinterpret, I am not saying anyone who lowers their car is a poser. Far from it. Lowering the car can have some (slight?) legitimate benefit to handling. But to get the most out of your car, you have to look at the whole package. Springs, dampers, anti-roll bars as well as wheels and tires.

I said slight. How slight? TireRack did an interesting comparo of a stock 3-series (non-sport) vs two others with H&R and Eibach lowering springs on them. Did it improve their lap times? You bet. Was it significant? 1%. What did you get in return? Stiff ride, worry about parking ramps.

I am NOT saying you need a pillow soft Lincoln Continental ride. The non-sport package is too soft for my taste for fast driving. The sport package is better. But there is the law of diminishing returns. You can keep lowering and keep lowering, but beyond a certain point, it won't help, but can really hurt.

To improve your handling you have to really look at the whole package, and decide what you really need. Don't be driven by fashion, but make a choice on a whole package that really does what you want. Or not. Its your car, and I am just a guy spouting my opinion. Good luck and have fun.

* roll center: The imaginary point on the cars longitudinal center line about which the car's suspension swings in reaction to roll forces.<p>99.5 1.8Tqms Laser Red
97 Jetta ]I[ 2.0 GL Gold
88 ZX-10 Red/Black

 

Finally!

 

I think most people lower their cars for the slight performance, but mainly cosmetic enhancements of less wheel gap.

 

(squat and dive). I've read articles that avocate against excessive sway bars because it reduces the independent action of the suspension. I even had a buddy who ran no sway bars and claimed that was the best handling setup.

If you're going to critique popular street trends that degrade handling, the obvious one to me is large diameter wheels with ultra low aspect sidewalls and extreme widths. A large contact patch with stiff, short sidewalls means the tire is not contacting the road over bumps. A contact patch that's too wide and too short also means loss of self-centering and stability, ie, poor tracking and feel.

 

No, this isn't a flame...not my style. But I do disagree with the basic gist of your post. Which as I understood it indicated that you feel that sway bars are a better choice for improving suspension than springs and shocks. This is rarely the case, and is definitely not the case with the A4. I've ridden in and driven A4's with a variety of suspension setups, and I'll tell you that the springs and shocks make a big difference in percieved handling. You said the Tirerack's article showed improvement in lap times of over .5 seconds, which is a lot on a 60 second course, let alone the 30 second one they used. Roll bars are better used to fine tune the car's balance (ie. dial in the desired level of over/understeer), and lots of folks here have added larger rear sway bars to their cars to do just that (dial in more oversteer, bringing the car closer to neutral). Several have the cracked subframes to prove it, this was caused by the largest bars on the stiffest settings, most people have gone to smaller bars (still larger than stock), and there are now supports for the subframe. Like anything else, sway bars come with trade offs, and that is they reduce the independence in the suspension. They also offer only incremental improvements in handling, less significant than those offered by a good spring/shock combo in the case of the A4. Of course, they're also less expensive. Of course if you want to talk about bang for the buck, I would say the best return for your money where handling is concerned is better and wider tires (biggest difference will be from non sport).

Now, in many cases, I would agree that lower springs are often for looks. Also, it can't be argued that stiffer springs and shocks can make the car tougher to control in corners on uneven pavement. Also, I don't get spoilers/wings (unless properly designed, but I never see downforce numbers in advertising)...they add weight and drag, but don't offer any benefits. I also agree with your point that none of us race our Audis (if you're not counting autocrosses and track events), more to the point, how many of us have ever pushed our cars to even 9/10 of the stock setup's capabilities? I would expect that very few have. I heartily agree that if you want a race or sports car then that's what you should buy, and I'll be doing just that in a few years (dedicated sports car...not a race car).

To sum up, first figure out what you don't like about your car's handling, then determine how to best address it, based on how you use your car, the conditions (road and weather) in your area, preferences for comfort, and budget.<p>Regards,
Rodney

'99 A4 1.8tqms

 

granted the cost will be greater. Though, I agree that a lot of suspension work is done for appearence.<p>Regards,
Rodney

'99 A4 1.8tqms

 

<p>99.5 1.8Tqms Laser Red
97 Jetta ]I[ 2.0 GL Gold
88 ZX-10 Red/Black

 

The best way to improve your car's handling is to get out to some drivers ed events and learn to drive your car. Most people benefit greatly from the techniques taught; and those that are already familiar with the techniques can always use some more practice. Besides, it's fun.<p>Regards,
Rodney

'99 A4 1.8tqms

 

A compliant sidewall will offer good contact with the road and better absorption of bumps and road irregularities. At the limit they may give away, but as this discussion has pointed out, most folks don't drive 10/10.

Thanks!<p>99.5 1.8Tqms Laser Red
97 Jetta ]I[ 2.0 GL Gold
88 ZX-10 Red/Black