jamesjedi

I am upgrading my 86 na stock torsion bars with 28 mm torsion bars. I want to lower it, as the bar is stiffer how many turns should I do? If one turn on a set of bars that have NOT been replaced with stiffer bars is good for 2 1/2 inches, how much less would my stiffer bar lower the car with the same rotation?

Potomac-Greg

Go to Clarks-Garage.com where there is an extensive write up on this. There is a formula and a write up that is so scientific and detailed that it convinced me to just buy coilovers.

Search "torsion bar index" here too.

krystar

lol greg.

it's not turns. it's clicks or splines.

joe made an extensive excel spreadsheet of this. search for torsion bar excel and u'll find it

jamesjedi

I have seen the Clarks-Garage...and read it about 15 times...Very funny!

jamesjedi

I looked at Joe P's sheet, perhaps it is not complete, or the more probable explanation would be that I am not smart or patient enough to fully understand it.

I guess I should try one spline, and see how low it goes? I do not want to do it twice. Which will probably be what I do.

krystar

well...what don't u get?

joe's excel lets u input the before TB, after TB, preferred drop. it then calculates how much angle is needed, how much height at the unloaded suspension should be. inner splines are 9degrees, outer splines are 8.8 degrees. figure out how many inners u need and how many outers u need to get close to the target degrees.

jamesjedi

I did not realize that it was a working spread sheet, the version I found was not a working spread sheet.

Here is the link;

http://az.pca.org/archive/tech/artic...barSetting.xls

Eric_Oz_S2

Not sure what your stock tbars are, but if they were 23, then going to 28 will raise the car by about 97mm. An inner spline click will drop by 67mm, an outer by 60mm. So do 2 x outer and the total drop is about +97-2x60 = 23mm.

333pg333

Also, if you don't already know, but going from 23mm to 28mm is a much larger change than it would appear. I don't have the actual rates to hand but it's amazing what just 1mm makes let alone 5. Unless you are changing other stuff this should entice a lot more tendency to oversteer.

jamesjedi

If I am using the Excel sheet correctly, two outer splines will result in a drop of 3.51 inches, or close to 90 mm? That sounds like allot.

krystar

yup it's alot. your tires will be probably tucking inside the wheel well or at least close to it.

make sure yer shocks can handle that drop

jamesjedi

The shocks are yellow Koni adjustable. Will they be OK?

krystar

yea u'll be fine with koni's.

jamesjedi

Thanks for help. I will be finishing it today or tomorrow.


Thanks again

jamesjedi

I have kids...etc. That job took far too long. My 0.001 cent opinion on the matter is that with the time it took away from the family, perhaps the coil over solution would have been a more reasonable route. Just a thought.