PFL Stock Rear Sway Bar Comparo - A3 vs S3

[S3_Miles]

So as some of you know I have both. I have also replaced the OEM Swaybars out of both.

I’ve read on here more than once that there is not only a belief they are the same sway bar, but also online most parts catalogs suggest they are by part number.

I’m here to tell you they in fact are different. The S3 is thicker both visually and by caliper, but additionally they have different part numbers.

Here are the photos:





Part number out of my 2016 A3 Quattro: 5Q0 511 305 BD
Part number out of my 2015 S3: 5Q0 511 305 BE

Diameter differences -
5Q0 511 305 BD: 21mm
5Q0 511 305 BE: 22mm

Considering the dimensions of some aftermarket bars out there, an upgrade to the OEM S3 discard bar for the A3 guys might be a frugal alternative to add some better rear handling. It’s 1mm, sure but that can make some difference. The neuspeed bar I run on my S3 is 25mm and the EMMotion bar from Emmanuele on my A3 is 23.8mm

The upside to the aftermarket bars is you can run different positions and adjust the firmness, along with the diameter overall being thicker. I suppose if you had access to a drill or better, drill press you could drill another set of holes in the oem S3 Bar that were closer to the center to give added firmness.

Just so everyone knows I would not do this myself. The point of the post was to answer some DMs I got around comparisons between the two PFL 8V cars. I got more than once about Rear sways comparing EMD to Neu, etc

[MikTip]

Wow!

1mm

[S3_Miles]

Wow!

1mm

LOL well...some guys wanted to know. In fact they are different. So there you go.

[MikTip]

Guess Audi figured 1mm separates an "S" from the rest...

[Coolrunning]

Guess Audi figured 1mm separates an "S" from the rest...

And then most of us add another 4mm 😂

[MikTip]

Audi tends to build'm conservatively for the masses...

We tune and tweek to or personal tastes.

[texasboy21]

There is considerably more to a sway bar than the diameter. Get a weight of both bars.

The B6/B7 guys swore up and down the A/S/RS front bars were all the same (just because the diameters were all 32mm). The RS4 bar weighed nearly twice as much as my A4 front bar... same diameter, more weight, and a different part number. Upon driving impressions is was obvious the RS bar was much more rigid as understeer was re-introduced.

[S3_Miles]

There is considerably more to a sway bar than the diameter. Get a weight of both bars.

The B6/B7 guys swore up and down the A/S/RS front bars were all the same (just because the diameters were all 32mm). The RS4 bar weighed nearly twice as much as my A4 front bar... same diameter, more weight, and a different part number. Upon driving impressions is was obvious the RS bar was much more rigid as understeer was re-introduced.

I ended up tossing my A3 OEM bar...so someone else will have to measure the weight on the A3 bar. Ill measure the weight on the S3 bar. Its a good point to make.

Not sure why im holding onto the OEM S3 bar.

[MikTip]

The S3 bars are light...hollow...

[Oneill_1952]

What end links are you running on your upgraded sway bars? i have been looking around but i cant justify some of these prices...

[PINGERS]

What end links are you running on your upgraded sway bars? i have been looking around but i cant justify some of these prices...

A lot of people stick with stock until they fail. I may end up going this route.

[S3_Miles]

What end links are you running on your upgraded sway bars? i have been looking around but i cant justify some of these prices...

Neuspeed. I opted for their billet endlinks. When I saw that the stock ones are a "glass-filled poly", I said nope

[MikTip]

What end links are you running on your upgraded sway bars? i have been looking around but i cant justify some of these prices...

MOOG K750809 $18

https://www.rockauto.com/en/catalog/...+bar+link,7580

[MikTip]

$14

https://www.ebay.com/itm/Rear-Stabil...-/222928514271

[Oneill_1952]

$14

https://www.ebay.com/itm/Rear-Stabil...-/222928514271

Thanks dude, do you not need adjustable end links to benefit from all the settings of an adjustable sway bar?

What can I use for fronts?

[Spinnetti]

Couple things that determine the spring rate of sway bars
- The material (though its probably the same across bars)
- The diameter; even 1mm does make a difference, though most of us want more than that. Note that hollow bars are lighter but have almost the same spring rate as solid ones as the center of the bar doesn't do anything (almost no relative motion) so hollow is generally better.
- The effective arm length. Shorter is stiffer, so when comparing check that too.

Back in the day, the B6 A4 and S4 bar were only 1 or 2 mm different too (I forget exactly) but I put the S4 bar on my A4 and it did make a difference; was a much better handling car than the A3/S3.

[texasboy21]

Couple things that determine the spring rate of sway bars
- The material (though its probably the same across bars)
- The diameter; even 1mm does make a difference, though most of us want more than that. Note that hollow bars are lighter but have almost the same spring rate as solid ones as the center of the bar doesn't do anything (almost no relative motion) so hollow is generally better.
- The effective arm length. Shorter is stiffer, so when comparing check that too.

Back in the day, the B6 A4 and S4 bar were only 1 or 2 mm different too (I forget exactly) but I put the S4 bar on my A4 and it did make a difference; was a much better handling car than the A3/S3.

16, 18, 20, 22mm respectively for the B6 A4 non-sport, sport, S4, and RS4.

[Spinnetti]

16, 18, 20, 22mm respectively for the B6 A4 non-sport, sport, S4, and RS4.

Nice.. Mine was an 02' sport. I remember wishing I had put on the RS4 bar (mine was a 1.8TQMS). It was enough with the GTx28RS to get me in trouble anyway ;)