Spring rates

[bracketracer]

At a 100% or close to that won't work on all cars...........So why did I buy shocks for the back of my car then

[BillyShope]

At a 100% or close to that won't work on all cars...........So why did I buy shocks for the back of my car then

Please view my post in another thread in this same forum.
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[Bob West]

Stored energy in suspension springs is of no concern in a dragcar ??? It sure is if you are running a small tire and you need transfer to hook it. My car came to life after installing Santhuff springs up front

[BillyShope]

Stored energy in suspension springs is of no concern in a dragcar ??? It sure is if you are running a small tire and you need transfer to hook it. My car came to life after installing Santhuff springs up front

We don't disagree. We're just not using the same words. You profited from a lower spring rate, not from what is normally defined as stored spring energy.
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[want-a-be]

Stored energy in suspension springs is of no concern in a dragcar ??? It sure is if you are running a small tire and you need transfer to hook it. My car came to life after installing Santhuff springs up front

We don't disagree. We're just not using the same words. You profited from a lower spring rate, not from what is normally defined as stored spring energy.
http://home.earthlink.net/~whshope
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It's what I consider stored energy.

[bracketracer]

Stored energy in suspension springs is of no concern in a dragcar ??? It sure is if you are running a small tire and you need transfer to hook it. My car came to life after installing Santhuff springs up front

We don't disagree. We're just not using the same words. You profited from a lower spring rate, not from what is normally defined as stored spring energy.
http://home.earthlink.net/~whshope
over 150,000 page views

So Billy if that is not "Stored energy" in Bobs front springs then what do "you" call it????????? And tell us what you define as "stored energy"

[BillyShope]

So Billy if that is not "Stored energy" in Bobs front springs then what do "you" call it????????? And tell us what you define as "stored energy"

I'm using the terms "spring stored energy" and "spring rate" as they're defined in any physics book. If you'll look again at my post on the first page of this thread, you'll see that I described two very different cars with two very different amounts of stored energy, but with the same spring rate. When the same amount of weight is transferred from the front of each car, the upward travel of each is the same and is calculated by using the spring rate. Yes, spring stored energy is lost during the upward travel, but the change in spring stored energy is not used to calculate the amount of travel. In fact, the total potential energy at the front of the car is not "lost" at all. It's form is merely changed. The change in spring stored energy is converted to stored energy in the form of "energy of elevation," as, again, the physics books call it. In other words, the mass of the front of the car is raised. When the car is brought back to the pits, the front ride height has returned to its pre-launch value and the spring stored energy has also returned to its pre-launch value.

So, if the spring stored energy is only temporarily altered in form, but eventually returns to its original value, it's not of much use.

But, when the spring rate is used to calculate the change in front end bumper height, we see that something else has happened which can definitely be of use. The center of gravity height has increased, which means more weight transfer to the rear wheels. And, if you can't otherwise pull the fronts on launch, lower spring rates...and the resultant higher CG...can definitely be desirable.

Of course, everyone's free to use words as they like, so, if you're not going to be calculating anything, anyway, it's perfectly all right to use your own definition of "energy." I'm just trying to help those who might want to finally get a chance to use what they learned in high school physics. (I've taught physics in both high school and college and students were always asking, "When am I ever going to need this junk?".)
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[BracketNova]

Sounds like we need to just replace the shocks and srpings with a solid bar then so that we won't have to worry about it. PLus think of the money we could save. em dare shocks and springs are spensive.

Hardtail dragster???

[nj]

Bracketeer,
Want-a-be is entirely correct and the important words for you to pay attention to are "stored energy." With a softer spring, which compresses more, so we can "preload" the spring more. The trick is to better use the amount of spring stroke you have available in your coil springs. A spring with more stroke (made available with thinner wire diameters and fewer coils) will compress more and store more energy.
Just take this as an update, NHRA Pro Stock cars weigh 2350 pounds, so at 2160, you're way over-sprung.
In my seminars, I explain this concept...
Imagine you have a weight of 600 pounds resting on your spring. A 200-pound spring will compress three inches once the 60 pounds is placed on the spring. This means that we will need 200 pounds to compress the spring when placed in the car. It will take 200 pounds to raise the fender by one inch, or 200 pounds to compress the spring by one inch. If you replace that spring with a 150-pound spring, it will compress four inches. It will also take 150 pounds to raise that fender one inch, or 150 pounds to compress that fender one inch. What is the result? The car is springier, or bouncier. In other words, it pitch rotates faster and give us better weight transfer. The only problem is that the front of the chassis will have to raise four inches before it yanks the front tires out of the beams, instead of the three inches you had with the 200-pound spring... so your reaction time will probably get slower, even though your traction is improved. The trick is in having three inches of suspension travel (for the better reaction time), using the 150-pound spring (better traction.) But you've already done the math, right? YOu multiplies 3 X150 pounds = 450 pounds and you have 600 pounds of weight on the spring. You're thinking that you can support 600 pounds of load with a 150-pound spring and three inches of travel. BUT, what if you raised the bottom of the 150-pound spring one inch (or in other words, preloaded the spring.) Now you have stored 150-pounds of energy in the spring and when you add the 150- pounds of stored energy to the 450 pounds you got from the three inches of travel and 150-pound spring, guess what, you have 600 pounds of spring force to support 600 pounds of weight. You made a 150-pound spring do the work of a 200-pound spring. Always pay attention to how high the lower platforms are on your coil-overs because when you are able to compress the spring more, you are better able to store energy in that spring and improve traction. I'll bet you a hot dog that if you try to use those 125-pound springs on your light car, you'll get instant spin.
I hope this helps,
Dave

Dave so if you have a car that has a 110 lbs rear spring and the bottom spanner nut is all the way to the bottom (No more adjustment to lower ride height) you could put a lighter spring say 85 or 95 lbs raise the bottom spanner nut to get your ride height with the same result as the 110 spring?

[bracketracer]

NJ..........I had 125lb springs in the back of my car. And they needed to be set at 16"...With the car jacked up and the rear hanging they would be off the adjuster nuts a good inch or so....I went to a 110lb spring and had to crank them up to get me 16"....So now I have some "stored energy"....But billy calls it something else