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Double-stacked rear sway bar
Posted: Tue May 11, 2010 9:01 am
by Bill K.
Another suspension mod for the Coupe...
1. Two 17mm rear sway bars from 4-speed 411/412
2. 944 front sway bar drop links
3. 17mm Prothane bushings
The 944 drop links are made of 10mm treaded rod (vs 8mm stock). They are rated for a 30mm hollow sway bar and a much heavier car. The bushings are 17mm - same as 411/412 rear sway bars. They fit perfect, have bushings that are available, and are strong enough to handle the increased load transfer. A broken drop link would be a very bad way to exit a corner... upside down.
The Prothane bushing make coupling the bars very easy and avoid binding.
The stock bushings were replaced with the same Prothane bushings, but a 1" rasp was needed to modify the width and height to fit the stock mounting brackets.
The results are excellent! Body roll is significantly reduced and the tires are working noticably (audible) harder. It corners so well that I've considered replacing the cushy stock front seats with one's having firmer side bolsters, but in memory of Travis I won't.
Buckle up and hang-on,
Bill

Re: Double-stacked rear sway bar
Posted: Tue May 11, 2010 6:20 pm
by bradey bunch
Looks great Bill! I guess I will have to find another rear swaybar this summer!
Re: Double-stacked rear sway bar
Posted: Wed May 12, 2010 3:35 pm
by raygreenwood
You did pretty much what I did. Nice work ! I have stacked rearsway bars on mine as well. One is the 17mm straight bar from a coupe and the other is the late 15 ish mm cranked bar from a four door. This is a world of good change. It changes the whole feel of the car.
The 411/412 had the habit of leading with its back end in curves. Its an almost Porsche 911 style handling issue. When going around a sweeping curve at speed, the heavy rear-end tends to float a bit without adequate sway control. The stock sway bar is very well calibrated for progressiveness....its just too small for the mass and enertia. When the rear starts to roll a bit...it litereally twists and lifts teh whoel car changing the steering input in the front end. My original thinking 8 years ago when I installed stacked "stock" sway bars is that the progressiveness of the original bar...simply doubled.....might help. It did very well.
In addition to having the audi 4000 strut mod in the front end, bronze idler, urthane radius arm bushings and delrin control arm bushings.....this mod....actually makes everything else perform much better.
Great work! Let us know how you like the results. I clamped mine together just a bit differently....but its the same effect . You have done well! Ray
Re: Double-stacked rear sway bar
Posted: Wed May 12, 2010 6:27 pm
by Bill K.
Thanks for the idea Ray. I found it also commonly done on old Saab's, but the 412 mounting is a bit trickier. I'm very happy with the mounting solution.
Before this upgrade, having 1 rear sway bar, the car handled great. But now it is much better. I will have to go to the track to find the limits safely. On the street, it handles all of the power the 115HP motor has without doing "crazy stuff". The car leans a bit in a corner, but is firmly planted in the rear. Full throttle no problem. It's a great engine/transmission/tire/suspension/brake combo for a daily driver.
I'll put the datalogger back in the car and do a g-circle sometime.
Re: Double-stacked rear sway bar
Posted: Thu May 13, 2010 1:15 am
by Hulken
The brackets holding the bars together, where do they come from? Any parts number of the bushings?
Re: Double-stacked rear sway bar
Posted: Thu May 13, 2010 3:59 am
by VW 612 RS
Hulken wrote:The brackets holding the bars together, where do they come from? Any parts number of the bushings?
Hello Arlid!
I baught my 25 mm bushing at this company:
http://www.energysuspensionparts.com/Un ... shings.asp
Just put 2 pieces together
I had them here i Norway 8-10 days after ordering
Hans Olav
Re: Double-stacked rear sway bar
Posted: Thu May 13, 2010 9:26 am
by raygreenwood
By the way....there are numerous cars that use virtually identical outer links to those. Some of the 80-90's golfs, jettas or audis have those....check passats as well. I cannot remember which car I took them from by I have several just like them.
You WILL need updated outer links like Bill is showing. This mod snapped one of my original outer ninks and I nearly rolled the car. Ray
Re: Double-stacked rear sway bar
Posted: Thu May 13, 2010 4:48 pm
by Bill K.
Hulken wrote:The brackets holding the bars together, where do they come from? Any parts number of the bushings?
19-1116-BL by Prothane Motion Control - brackets and bushings come together. Black version has graphite loading. Many people think Prothane are a bit stiffer than Energy Suspension, but probably doesn't matter.
944 end links are 95134307500, outer bushings are 951343793
30 (NOT 951343793
00) and rod bushings 95134379501. I bought used assembly on ebay.
Re: Double-stacked rear sway bar
Posted: Fri May 14, 2010 7:56 am
by Hulken
Hello Hans Olav,
Where did you pick your rear swaybar - Porsche? Pictures of your assembly would be nice.
Re: Double-stacked rear sway bar
Posted: Fri May 14, 2010 8:27 am
by VW 612 RS
Hulken wrote:Hello Hans Olav,
Where did you pick your rear swaybar - Porsche? Pictures of your assembly would be nice.
Pictures will come. I´m not finished with it yet

Some picture of the front swaybar you find here:
http://shoptalkforums.com/viewtopic.php?f=12&t=131054
Both swaybar is special made for this car. Made by steel who´s used for swaybars and coilsprings.
I will make to set of swaybars. 22 and 25mm for both front and rear.
Then I will test witch setup who works best.
Hans Olav