Does anybody on here know how to figure out a ballpark rating of a custom leaf spring? I can provide the thickness, lenghts, and number of leaves.

I started with a 7-leaf Deaver steel spring from Toms diff that was a 360lb rated. Then swapped to a shorten main leaf so I can run it with my offset T-arms and run a 15x10 back wheel(5" BS). Then I took the original main leaf and chopped ends and added it to the spring pack to make a custom 8-leaf pack. I would like to know what rating I'm at now with shortened main leaf and extra leaf added?

This is for a 550rwhp stick shift car that will be drag raced. I already run QA1 adjustable shocks and run them at full stiff setting with my old 7 leaf spring. I was having issues with the car squating to hard and even bouncing in the rear on hard launches at the strip. When I checked the specs on my old spring it was only a 305lb 7-leaf made by Triangle. Even with the QA1 shocks that spring wasnt enough. I was told by a few corvette drag racers to try and get a stiffer spring and "the stiffer the better" with a stick car. Also from what I researched i guess steel is a much better option then fiberglass at the drag strip

I'm guessing my new custom spring is around 400lb rating now but Im not sure and was hoping there was a calculator, program, or formula I could use to confirm the rating.

I will get measurements on spring if anyone can help me, Thanks

 

To many variables to calculate. I believe that steel multi leaf are not linear. As you compress the rear more leafs come into play. I re-arched my steel and added a leaf and it had to be over 500# But it was perfect for drag racing with goodyear slicks.

I have since tried a 420# mono and it was too wimpy so I had Vette Brake make me a 520# Firm but I'm working on how to set it with my Koni adjustables

 

Found this figure in a google search for "multi leaf spring rate"


Figure was on this page:
http://www.timskelton.com/lightning/...sion/leafs.htm


Also found this calculator in a search for "leaf spring rate calculator":
http://www.therangerstation.com/tech...springrate.htm

I don't know how good these are or if they're even close. Let us know what you come up with!

 

I tried to use the webpage posted above and input my numbers but the calculator on that page doesnt work, it just doesn't do anything at all when you hit enter. lol

So I used the formula and did math by hand.

I came up with:

361lbs/inch at original standard length 7 leaf Deaver

425lbs/inch 7 leaf with ends shorten 1.25"

486lbs/inch 8 leaf with shorter main leaf.


Numbers seem pretty high to me. I didn't realize that shortening the main leaf 1.25" each end would cause such an increase in rating.

 

Actually, that wouldn't surprise me too much. You're removing easily the most flexible part of the assembly by a wide margin.

Hey Kid, did you up the ante on your engine? That's a serious amount of RWHP!

 

The numbers for the standard 7 leaf do seem a little high, but the increased amounts from the modifications seems to be realistic.

According to the Duntov site, the standard 9 leaf spring was 196 lbs/in and the 7 leaf was 330 lbs/in.

 

Changed nitrous tune up and made a few tweaks with spark plug gap and fuel pressure. Car made 410rwhp @6-7psi of boost... 493rwhp with 100hp shot... And 541rwhp with 150-175hp shot.. When spraying it on dyno the boost jumped to 10psi. Idk why lol

 

Wow, looking forward to seeing how you do when you make some passes- hopefully with video.