I'm not a rocket scientist, but I'll guess the result will be the opposite of when you move it outward  one inch.

Since the spring perch will now be closer to the ball joint I think it will effectively make the spring stiffer since it is now farther away from the "fulcrum" which is the UCA pivot shaft. Think of the UCA as a lever and you are the upper ball joint trying to lift the weight of the car.

Last edited by Texas! (9/04/2022 12:18 PM)

When I was rebuilding my suspension a few years ago, I made the additional holes to relocate outboard 1” closer to ball joint.

Everything remained the same including shock settings on my coil overs.

Here is what my results were:

1) Raised the front end of the car
2) Camber became more positive
3) Suspension resisted compression with same force pushing down
4) Reduced nose dive with moderate/hard braking
5) Ride became too harsh…too darn stiff

I stopped about 2 miles and changed my shock settings from 7 compression/14 rebound to 5 compression/10 rebound.

Front feels firmer than original setup, but  nowhere as harsh from first test drive.

I did an experiment with my KYB Gas-a-Just shocks/spring perch/spring setup but couldn’t drive it in winter.
I noticed the same effects just never drove it like that.

Figured I’d share the information.

Perhaps an engineer can explain all of the effects…I can’t.

There might be limits with stock style springs as the diameter and spring perch may interfere with tires or other suspension components.

I plan to try it out as I head to visit family and the Bash.

Last edited by Nos681 (9/04/2022 1:20 PM)

I thought that if the spring is vertical….low spring rate.
At steeper angles…higher spring rate.

Now in this situation, the pivot point is being moved at the same time as the angle changes.

If you take the measurements and compare the ratios, you can tell exactly what the change will be. It will be stiffer. It will not change the camber curve. It will likely cause the tire to rub the spring perch if you have aggressive wheel backspacing.

Seems like a cheap, easy way to stiffen the front end, if that is your goal.

Nos681 wrote:

I ran across this information today at Opentracker.

https://opentrackerracing.com/shop/spring-perch-move-1-template/

I made one of these when I did the my Shelby drop years ago, working well.
 

BobE, this template is for spring perch relocation outboard on upper arm.

I was referring to results of spring perch.

I originally tried it with my 620 springs and KYB Gas-a-Just shocks, just never drove it due to winter.

I did see ride height change and effort to compress front suspension.

With the springs I had, I still had tire clearance.  Just depends on spring diameter and design shape.

It was most likely that I found it on Opentracker, I just don’t recall what to expect…other than “motion ratio” was thrown around a lot back then.

Now I understand the concept better after doing it myself.

I’m still learning.

And this was a “time cost” project of making a template and drilling 4 additional holes in a piece of scrap sheet metal.

Fits my budget perfectly and easily.