Audi A3 Rear Sway Bar

[AJGD1992]

Hi everyone,

I just bought a 2018 Audi A3 2.0T Quattro Premium Plus. I am thinking of modifying the rear sway bar to a 034 Motorsport MBQ. I’ve read that it does not sacrifice ride quality and makes cornering much sharper. Please let me know your thoughts on its performance factors and any other feedback you may have if you have modified your car’s rear sway bar.

Thanks,

Austin

[Chaoscreature]

I would recommend reading an article on what sway bars are and how they work. http://speed.academy/how-swaybars-work/

I have the 034 Motorsport Sway Bar on my A3 Quattro. It did make a handling difference, but it will not affect the initial turn-in feel or make the steering "come alive". A Front Sway Bar will net you more immediate improvements to the "feel" of the car.

I know some other people will critique my recommendation, so I am going to address that ahead of time.
IMO there is a difference between "handling" and what I call "perceived handling".

Proper handling is when the car does what you want it to, although this may not always feel good. A lot of AX cars driven by much better drivers then me like a very loose car (esp FWD cars). Soft front springs, no front roll-bar, big rear sway bars. The cars feel like wallowy turds, and someone not used to driving a car like that would say that the car "handled" terribly. Nope, the car handles fine, but it feels awful. In general, sticky tires, a bias towards oversteer, and properly suited alignments to your driving style and track conditions will make a car handle appropriately.

"Perceived Handling" is more of a visceral feeling that the car is communicating with the driver and doing what you want it to do. Basically, if the car has decent steering feedback and good initial turn-in then most people would be content with the cars "handling". Front sway bars, larger wheels, stiffer sidewalls and sensitive steering boxes all lead to a car that has very good perceived handling.

Austin,
Since you didn't mention any specific handling attributes that you want to address, I assume that you just want to make your car feel more connected. For free, check your tire pressures. A lot of shops will set them too low for your car, which will make the steering feel even spongier (and the steering feedback on the Audis is atrocious already).

[Spinnetti]

I'm odd man out in that I don't really care much about steering feel. I just want it to do what I want it to do. $7k in mods, and I'm still not there yet. I've got the 034 rear bar with the bar ends and set to the stiffest setting (stock front bar). When you read up on sway bars you will find it has virtually no impact on ride quality except I suppose on one-wheel impacts (nominally worse on a hump, better on a dip). Yes, it helps and is the first mod I do on any VW/Audi (well except the R8) but doesn't help enough. up to 8/10ths is as good as any car on the road. At 9/10ths it starts to complain and won't dance then at 10/10ths it falls apart and understeers way too much even with a boatload of mods. Next step is to try a bit more toe out on the rear as it simply will not rotate. BF Goodrich used to have a little wallet card with guidance on all the stuff you can do to change the handling of your car. Camber, Caster, Toe, Tire pressures etc.. very handy. I think I'm at 39 front and 35 in the rear right now and running more camber up front (034 camber plates and springs) and less than stock in the rear. You can run more toe out than stock up front if you want better front end feel, but only a little or it will wander at high speed. Considering staggered tires since it needs about 2x the rubber in front as it does in the back. As you can see, endless possibilities... There's lots of good books on suspension theory and setup too - I've got a bunch. All that aside, its the best first handling mod, so go for it - I only wish it was stiffer.

[Chaoscreature]

Spinnetti,
34 seams pretty low in the rear. I generally run 40 all around for commuting, then play with the tire pressures at the track until I get proper tire rollover. Try running 39 all around to get the car more neutral. Granted, I have not tracked my A3 yet... so I might be totally off my rocker!
The lack of steering feedback in these cars is almost entirely due to the front control arm bushing design, which allows for a LOT of deflection and loss of toe control when cornering. Replacing the rear bushing with a spherical bearing will make a huge difference in precision and feedback.
If only someone made a spherical bearing kit... @034Motorsports :)

[Spinnetti]

Spinnetti,
34 seams pretty low in the rear. I generally run 40 all around for commuting, then play with the tire pressures at the track until I get proper tire rollover. Try running 39 all around to get the car more neutral. Granted, I have not tracked my A3 yet... so I might be totally off my rocker!
The lack of steering feedback in these cars is almost entirely due to the front control arm bushing design, which allows for a LOT of deflection and loss of toe control when cornering. Replacing the rear bushing with a spherical bearing will make a huge difference in precision and feedback.
If only someone made a spherical bearing kit... @034Motorsports :)

034 makes rear control arms with spherical joints... I have them installed ;) I've also got 255 tires all around right now, so I could run the rears at 20psi and not even notice.. the front carries a lot more load, so gets more air. In my race car I would run starting pressures in the 20's mid-summer, high 30's hot (I use a pyrometer to set pressures). I'm getting zero roll over in the back even with less than stock camber in back. I actually need more grip in front and less in the back, so thinking to downsize back to 235 in the back. Wonder if there is a 265 fitment for the front.... hmm.

[jon-stuver]

RSB did not really change the feel of the car for me much. When I put the FSB on I noticed a bit more of a difference. Gave me a little more confidence going in to the turn too.

[Chaoscreature]

034 makes rear control arms with spherical joints.

I meant front control arm, rear position. The design would be almost identical.
Running the rears at a higher pressure then needed is what gives the car a more neutral feel. Of course they don't need the extra pressure to support the weight, it's all about managing grip.
When I adjust tire pressure at the track, I will set the front tires to give me the appropriate rollover (using the the little triangles on the sidewall, see image below) and then adjust the rears to dial in over/understeer to suite my mood or the driving conditions.

You gotta be careful though... too loose of a rearend can make for some real pucker moments!

[Spinnetti]

Looks like you need to get yourself a pyrometer... roll over tells you a little but not that much. On the street I don't like running real high rear pressures to get it to rotate as the tires wear in the crown quickly. I'll adjust the rear toe a bit instead. The handling in the S3 is so dead it would take quite a lot for anything to pucker. Best of the VAG bunch I've had is a MKV GLI. I put the 034 rear bar on that with some H&R supersport springs and it would drop throttle oversteer like a champ. I'd still be driving that but got taken out by a careless driver. I'm hoping to get the S3 to handle as good as the GLI, but not there yet.

[Chaoscreature]

I completely agree, a tire pyrometer will tell you a lot more about whats going on then just checking rollover. BUT, tire rollover tells you a lot very quickly, easily and without having to run around the car like a madman getting multiple tire temps per tire to determine the temperature profiles.

RSB did not really change the feel of the car for me much. When I put the FSB on I noticed a bit more of a difference. Gave me a little more confidence going in to the turn too.

This is exactly what I would expect. The front sway bar will make the steering feel more precise, but will contribute to the cars tendency to understeer IF you push the car hard enough.

For those interested in reading about tire temperatures and what they tell you here's a fun to read article below:
https://nasaspeed.news/tech/wheels-t...the-racetrack/

[S3_Miles]

2015 S3 - Added a Neuspeed RSB with the billet links. Set to stiffest. Noticed right away and love it.