yessamgerg

You absolutely need to correct for force at the spring. The load at the shock tower can absolutely be more than the weight of the car. You clearly haven't studied engineering as you need to consider the effects of internal and external forces. The weight of the car is being supported by the tire through the lower control arm and then the spring. The force on the tire is magnified through the lever ratio of the lower control arm. This is called the motion ratio. I am not discussing roll ratios at all, just ride dynamics.

You are assuming that the shock tower force is equal to the weight of the sprung mass, this is absolutely incorrect as there are other internal forces in play.

yessamgerg

Ok I was using your claim from the other post of 120-140 lbs lighter. This list actually makes the situation worse for you though. Exhaust saves almost all of its weight from behind the rear axle from removing the stock mufflers. Due to the cantilever effect a pound saved removes at least a pound from the rear axle. Soft top is entirely over the rear axle. Seats are much closer to rear axle than front. Spare and trunk, again all rear axle. So you have saved 90 lbs entirely off the rear axle of the car.

B serious

Well...the car weighs a finite amount. Lets say 600LB.

If you compress a 447LB spring by 1.34", it will lift the 600LB shock tower.

You cannot use the LCA as a lever to compress the spring further...because it will just lift the car rather than compress.

At 1.34" of compression, a 447LB spring acts like a solid, incompressible peice if you're using it to lift 600LB.

B serious

If the car was a FIXED object, then using 700LB on a lever would result in compressing the spring by the lever ratio.

yes?

B serious

A car cannot weigh more at the shock tower than it weighs at the shock tower.

If you were to remove the springs and let the wheels fully touch the ground and let the full weight of the control arms, etc rest...you could put scales under the shock tower and get a FINITE UNSPRUNG weight.

How can you compress the spring more than that unsprung weight will allow?

Or:

-Why has my 447 LB spring only compressed 1.53"?

yessamgerg

It can have more force on the shock tower than the weight of the the car if there is another force also pulling the body down. In this case if you think about the lower control arm forces there is a force up at the outer ball joint. To react that force there is a force at the damper attachment. This however makes a moment which requires an additional force up at the in board upper control arm pivot.

Thus your beloved shock tower hasn't the weight of the car plus this EXTRA force from the LCA attachment. Your ignorance of physics does not change the fact that everyone who has ever studied suspension know that spring force is almost always significantly more than the mass to the sprung components.

B serious

Ok. Lol well...lets put personal insults aside.

I'm afraid I don't see the sense in what you're saying.

What other force besides gravity pulls the body down?

And why did my 447LB spring compress by 1.53"? Remember, the 1.53" INCLUDES the cosine factor.

yessamgerg

Perhaps because there is a ton of stuff you haven to accounted for. For instance, how much force does it take to overcome the gas charge of a DFV. I know the exact amount, you didn't account for it. What is the effect of the bushing on the wheel rate assuming you didn't relax them at your new ride height. How does the rate of the spring change without thrust bearings on each end? Is your 447lb spring still remotely close to 447?

B serious

I clocked my bushings.

what does the airspring charge of the DFV equate to in LB?

B serious

Why did you not account for the same air spring charge in your earlier calculation?