Torsion bar reindexing for KW V3
02-07-2010, 07:03 AM
#1
Rennlist Member
Thread Starter
Join Date: Jul 2001
Location: Brisbane, Australia (Formerly: Sunnyvale, CA)
Posts: 2,120
Likes: 0
Received 3 Likes
on
3 Posts
Torsion bar reindexing for KW V3
How much lowering required to compensate?
My car is already lowered about 1" from stock, and I thought I'd like to keep it that height after installing the KW V3s.
What I was thinking of doing was to install the KW V3 rear coil-overs, measured to see how much the rear is lifted, and reindex using the calculation +1 outer spline -1 inner spline = ~0.25 in. So if the car was lifted 1", I'd reindex +4 outer splines -4 inner splines, for example.
Then it occurred to me that people have already installed the KW rear coil-overs before reindexing, and can tell me exactly how much the rear suspension lifted... anyone?
Interestingly, in the KW installation manual, they suggest adjusting the eccentric bolts on the spring plate as the method for adjusting the torsion bars. Given that the total range of adjustment for those eccentric bolts is ony about 1" of height adjustment, that suggests the lift isn't very much at all.
Or that the KW installation instructions are somewhat bogus in this regard.
Comments?
My car is already lowered about 1" from stock, and I thought I'd like to keep it that height after installing the KW V3s.
What I was thinking of doing was to install the KW V3 rear coil-overs, measured to see how much the rear is lifted, and reindex using the calculation +1 outer spline -1 inner spline = ~0.25 in. So if the car was lifted 1", I'd reindex +4 outer splines -4 inner splines, for example.
Then it occurred to me that people have already installed the KW rear coil-overs before reindexing, and can tell me exactly how much the rear suspension lifted... anyone?
Interestingly, in the KW installation manual, they suggest adjusting the eccentric bolts on the spring plate as the method for adjusting the torsion bars. Given that the total range of adjustment for those eccentric bolts is ony about 1" of height adjustment, that suggests the lift isn't very much at all.
Or that the KW installation instructions are somewhat bogus in this regard.
Comments?
Last edited by Mark944na86; 02-07-2010 at 09:06 AM.
02-07-2010, 01:13 PM
#3
Instructor
Join Date: Jan 2009
Location: Puerto Rico
Posts: 152
Likes: 0
Received 0 Likes
on
0 Posts
what I understood from the previous posts was that you can keep the torsion bars reindexing them with the stock KW's V3 #285 rear coils and it would compensate with the tbars.
If you want to take off the Torsion bars you'd have to order them at least #450-#500, thats what I've read over here but then some people told me that'd be too stiff. Does #285 plus the torsion bars make the same kind of rigid ride as only #500 without Tbars?
If so, what is the pros and cons about leaving and getting rid of the torsion bar?
If you want to take off the Torsion bars you'd have to order them at least #450-#500, thats what I've read over here but then some people told me that'd be too stiff. Does #285 plus the torsion bars make the same kind of rigid ride as only #500 without Tbars?
If so, what is the pros and cons about leaving and getting rid of the torsion bar?
02-07-2010, 10:38 PM
#7
Three Wheelin'
So if the rear is, say, 1" too high with the coil-overs in, at a guess I'd need to reindex +8 outer -8 inner, for example?
Trending Topics
02-08-2010, 08:01 AM
#9
Three Wheelin'
I indexed mine (koni coilovers with 10" 250# springs) 1 inside spline, and could only drop it by about 10mm. With the 250 rate springs (similar to KW 280 rate), the reduction in height (from tbar = coilover installed) with each spline rotation is approx half. ie IIRC 1 spline inside = 68mm tbars only = 34mm tbars + helpers (ie equivalent to about portion of spring wheel rate divided by total wheel rate) . BUT, when you first install the coilovers with initial preload (as I had to - the springs were already slightly compressed on lowest setting before installation), the ride height went up 35mm - so I was back to where I started. I then had to use the spring plates which dropped it back about 7-8mm (again you only get half the effect based on the ratio of tbar rate to total rate).
I would suggest installing the coilovers first (lowest setting) and measure height change. Then add this increase in height to the drop you want to achieve (if any). Then reindex based on ration of springs (about 2.2) the change you require for the case if you only had tbars.
eg. if height increases 20mm, and you want to allow a drop of say another 20mm using the adjusters, reindex based on 40 * 2.2((137+280*.56)/137) = 88mm. You will end up adjusting both inside and outside to get it just right.
I hope this helps, I went looking for the same info when I did mine and ended up proving the point. I would have had it right but I had to screw up the collars (well actually down towards the ground for the inverted shocks) a bit to avoid hitting the spring plates thus adding additional preloading.
I would suggest installing the coilovers first (lowest setting) and measure height change. Then add this increase in height to the drop you want to achieve (if any). Then reindex based on ration of springs (about 2.2) the change you require for the case if you only had tbars.
eg. if height increases 20mm, and you want to allow a drop of say another 20mm using the adjusters, reindex based on 40 * 2.2((137+280*.56)/137) = 88mm. You will end up adjusting both inside and outside to get it just right.
I hope this helps, I went looking for the same info when I did mine and ended up proving the point. I would have had it right but I had to screw up the collars (well actually down towards the ground for the inverted shocks) a bit to avoid hitting the spring plates thus adding additional preloading.
