Torsion bars
It is simple math, but you got the physics wrong.
First, your example is clearly for a coil spring set up. Free height and installed height are totally meaningless on a torsion bar suspension, and that matters because unlike a coil spring set up you can't realistically preload the torsion bar. If the UCA isn't pinned to the upper bump stop then the weight of the car is the amount of stored energy. If you change the corner weights on a torsion bar car you're changing the height in the front.
Second, there is no difference in stored energy, not even in your example. The 100 lb spring compressed 10 inches and the 500 lb spring compressed 2 inches have EXACTLY the same amount of stored energy, 1000 lbs. They have different compressed heights, but the same exact stored energy.
So, why do drag racers want light springs? Well it has nothing to do with stored energy. It's about weight transfer. Which is about traction. To go back to the part of your example that you got right, when you mash the throttle you start weight transfer because of acceleration. And the car with 100 lb springs will rise 1" for every 100 lbs worth of transfer you get due to acceleration. With a 500 lb spring you only get .2" of rise for that 100 lbs of transfer. That means that the car with 100 lb springs will be higher in the front, which moves the center of gravity of the car further back, so, more weight on the rear wheels. Which means more traction.
But please note, the same amount of energy was released from the spring. The difference is the change in front end height and the additional weight transfer that occurs because of that change in height moving the CG, not a difference in the stored energy of the spring. The 1" rise in the 100 lb spring and the .2" rise in the 500 lb spring release the same 100 lbs of energy stored in the springs.
A spring is a spring is a spring. And, you are wrong.
I used a coil spring (as I said) because it's easier to visualize, but a torsion bar acts exactly the same way.
A /6 cranked up to the same ride height as a bar that is .880 diameter will have more stored energy. It HAS to. My physics is correct. Your understanding is what's wrong.
I'll say it again. If you have a spring with a 100 pound spring rate, it takes 100 pounds to compress that spring 1 inch. Very simple no?
Now look at a 500 pound spring. It takes 500 pounds to compress the spring 1 inch. You there yet?
Therefore, if what I wrote above is true and correct (and it is) then the exact opposite must be true. To extend the spring 1 inch on the 100 pound spring you must REMOVE 100 pounds from it. To extend the 500 pound spring 1 inch you must REMOVE 500 pounds from it.
You CANT possibly argue that.
Therefore, if you have two springs (IDGAF what type of spring it is, it is math and physics that has been proven forever and you can't change it) of different rates installed to the same height, the spring with the lower rate will have more STORED energy than the spring with the higher rate.
Therefore, it's always EASIER with a spring of a lower rate to move the front suspension with a lower rate spring. Period.
Let's say I need to move the front suspension 4 inches to get the best hook. With the 100 pound spring, I only need to remove (transfer) 400 pounds from the front end. Simple math. Can't argue that.
With the 500 pound spring, to get the same 4 inches of movement (transfer) you'd need to remove 2000 pounds from the front end. That's simple math. And you don't get to change it.
I can post the same math 5 more ways and you'll still argue because you don't get it. That doesn't mean you get to tell people something incorrect just because you don't know it.
The amount of front end separation is controlled by the rate of the spring. The RATE at which it separates is controlled by the shocks extension setting. FACT.
So what I've posted is 100% correct. Chris Alston agrees with me. Dave Morgan agrees with me. Tim McAmis agrees with me. Jerry Bickel agrees with me. Science and math agrees with them.
Sorry, but facts is facts. The simple of it is...the lower spring rate compressed to the same installed height has MORE stored energy. PERIOD. If you don't like my explanation, get the "Doorslammers" book by Dave Morgan. He explains it in more detail.
Not understanding spring rates and shock settings is why so many torsion bar guys leave ET on the table.
