Question: Rear Anti-Sway Bar Knuckle Attachment Mismatch
03-06-2013, 02:35 PM
#1
Question: Rear Anti-Sway Bar Knuckle Attachment Mismatch
Interesting question for those of you that have taken time to tweak your rear suspension or install a new rear anti-sway bar...
I have a 96 C4 and recently upgraded from a 24mm hollow to 26 mm solid ASB in the rear. I installed the bar with both wheels in the air and coilover shocks fully extended. So, the "geometry" on the right and left side should be symmetric.
Once I attached the passenger side of the bar to the knuckle, I noticed the driver side of the bar was at least an inch higher than on the passenger side.
So, in order to connect the driver side, I had to pull the bar down, which effectively reduces the driver side spring pre-load and increases the passenger side preload. So, the car sits with a lean to the driver side -- about 3/8" ride height difference from driver rear to passenger rear.
To compensate, I increased the coilover spring preload on the driver side and reduced the passenger side, which leveled the car. (Raised driver side spring seat 1/8" and dropped pax side 1/4".)
I verified the rear ASB bushings were both mounted "flat" to the cross-member, which might have caused the angle. So, I'm not sure what is causing the mismatch. I don't think the bar arms are out of parallel (didn't notice before install anyway). I had the issue with both factory trailing arms and heim links. So, I don't suspect bent arms distorting knuckle placement.
For those of you familiar with the C4 rear suspension, is this something common? Any idea of the cause or the corrective action? Conversion to heim links would allow me to form links of different lengths, which would address the mismatch, but I think that might be treating the symptom more so than the cause.
Thanks for any advice.
I have a 96 C4 and recently upgraded from a 24mm hollow to 26 mm solid ASB in the rear. I installed the bar with both wheels in the air and coilover shocks fully extended. So, the "geometry" on the right and left side should be symmetric.
Once I attached the passenger side of the bar to the knuckle, I noticed the driver side of the bar was at least an inch higher than on the passenger side.
So, in order to connect the driver side, I had to pull the bar down, which effectively reduces the driver side spring pre-load and increases the passenger side preload. So, the car sits with a lean to the driver side -- about 3/8" ride height difference from driver rear to passenger rear.
To compensate, I increased the coilover spring preload on the driver side and reduced the passenger side, which leveled the car. (Raised driver side spring seat 1/8" and dropped pax side 1/4".)
I verified the rear ASB bushings were both mounted "flat" to the cross-member, which might have caused the angle. So, I'm not sure what is causing the mismatch. I don't think the bar arms are out of parallel (didn't notice before install anyway). I had the issue with both factory trailing arms and heim links. So, I don't suspect bent arms distorting knuckle placement.
For those of you familiar with the C4 rear suspension, is this something common? Any idea of the cause or the corrective action? Conversion to heim links would allow me to form links of different lengths, which would address the mismatch, but I think that might be treating the symptom more so than the cause.
Thanks for any advice.
03-06-2013, 04:24 PM
#2
Safety Car
if you have coil overs that is why it doesn't match.
when you set the car (corner weight) the actual heights will differ that is why the adjustable end links are then used. So to answer your question use adjustable end links corner weight with one link disconnected, set the car on it's suspension (the ground) bounce it then adjust the end link to slide in easily. when corner weighting the car should be as driven with the drivers weight added to the front seat.
Most any good race shop can do this
when you set the car (corner weight) the actual heights will differ that is why the adjustable end links are then used. So to answer your question use adjustable end links corner weight with one link disconnected, set the car on it's suspension (the ground) bounce it then adjust the end link to slide in easily. when corner weighting the car should be as driven with the drivers weight added to the front seat.
Most any good race shop can do this
03-06-2013, 07:52 PM
#3
Drifting
turnbuckle length on the bars ends up being what ever it ends up being in order to not load (put any tension on) the bar once the ride height it set and the car is corner balanced with 1 side of the sway bar disconnected (both front and rear).
03-11-2013, 12:29 AM
#5
Thanks
Thanks for the responses.
I currently have fixed-length factory links installed, but they don't align well. So, I've ordered some heim rod ends that will allow me to use differing lengths on each side - front & rear.
Glad to know different length end links (from side to side) are of no consequence -- nothing to worry about.
I currently have fixed-length factory links installed, but they don't align well. So, I've ordered some heim rod ends that will allow me to use differing lengths on each side - front & rear.
Glad to know different length end links (from side to side) are of no consequence -- nothing to worry about.