Spring plate math

[47silver]

Our 72 is on a liftr. digital scale on the sill plate shows that the front end is 1.5?degrees lower than the rear.
My spring plate is reading 35.9 degrees.
Is the spring plate actually reading 37.4? And do i have to read ~ 34.8 do i need to get to 36.3 degrees?

[76FJ55]

Not sure I fully understand your question, but will do my best.

I assume you are on a 2 post lift or similar and the chassis is tilted front down by 1.5 deg. and the suspension is in it's fully drooped state.

if you are measuring a trailing arm angle of 35.9 with the car at this attitude, that would equate to 37.4 if the nose of the car was elevated to achieve 0 slope of the chassis.

the last bit of your question is a little less clear. I am assuming you have a target spring plate inclination (level chassis) of 34.8. if this is the case you would actually need to set the arm at 33.3 since raising the front increases the slope of the arm.

[47silver]

The first part is what I thought. So i need to measure 34.8 at the spring plate to achieve 36.3 or so (as calculated on the elephant racings calculator)

[76FJ55]

Originally Posted by 47silver

The first part is what I thought. So i need to measure 34.8 at the spring plate to achieve 36.3 or so (as calculated on the elephant racings calculator)

Yes, you will need to add 1.5 degrees to your measured angle.

[PeteKz]

What are you trying to achieve? Do you want to raise or lower the rear?

And, you should measure the door sill angle and spring plate angle with the car settled on the ground, so you can a calculate how much to change the spring plate angle to get the result you want.

[47silver]

Raising it, have it apart and did not measure. Ill try it at 36 and see what the measurements that porsche recommends

[E Sully]

https://www.elephantracing.com/tech-topics/spring-plate-angle-calculator/

[47silver]

i was using that calculator but was thinking that the tilt of the car would affect the reading
from what I read the sill has to be level when you measure the angle
Since my car is on the lift and it is tilting 1.5 degrees ilower in the front than the rear.
If I set the angle to 36.4 as Elephant recommends then I need to be at 34.9 degrees on the plate.
onh teh lift = 36.4
then on the ground it would be 36.4 +1.5 = 37.9

[E Sully]

Your on the right track. With the car angled 1.5 down at the front (red), If you want to end up with 36.4 level on the ground (black).

I used a protractor from bending electrical conduit that could be set to 0 on the sill, and just adjusted directly to the final angle. The guy doing corner balance and alignment has to fiddle with it later anyway.

[47silver]

Perfect, i have a similar tool