CadVetteStang
CadVetteStang New Reader
5/10/14 6:43 a.m.

My research has come up with conflicting information on the stiffness added to a coil spring by cutting coils:

I am working with a coil spring that has 8 active coils.

Once source states that each coil is 1/8 (12.5%) of the “give” in the spring, so cutting one coil off equals a gain of 1/8 (or 12.5%) in strength. If that is true, then cutting the spring in half would make it 1.5 times as strong.

The other source states that cutting a spring in half makes it 2 times as strong…. In that case, cutting one coil (1/8 of spring) would equal a gain of 2/8 (25%) in strength.

Edited to remove second part as it made no sense... it is too early and I am not awake yet. lol

but I do need some help figuring out ride height before I cut the newer/stonger spring.

thanks in advance,

        Cody
Zomby Woof
Zomby Woof PowerDork
5/10/14 7:30 a.m.

Google spring rate calculation, take some measurements, and calculate the new rate. Then forget it and cut 1/2 a coil at a time for the desired ride height.

CadVetteStang
CadVetteStang New Reader
5/10/14 10:59 a.m.

TOP: replacement spring (uncut) BOTTOM: stock spring [URL=http://s798.photobucket.com/user/kaywoodcove/media/0507141717_15.jpg.html][/URL]

According to the calculator, cuttiong 2.5 coils off makes it a 775# spring. cutting 2.7 coils off makes it a 805 lb. spring.

the stock 279# spring does not support the weight of the car. although, I like the height, I need to raise it about an inch to keep the exhaust from dragging in my driveway.

Here is the spring in the fully extended suspension: [URL=http://s798.photobucket.com/user/kaywoodcove/media/0507141600a.jpg.html][/URL]

CadVetteStang
CadVetteStang New Reader
5/10/14 11:07 a.m.

however, the coil spring calculator shows my stock 279# spring to be a 331# spring

fritzsch
fritzsch Dork
5/10/14 11:46 a.m.

Are you measuring the actual diameter of the metal in the spring? If there is some sort of coating that will throw your measurements off.

CadVetteStang
CadVetteStang New Reader
5/10/14 11:58 a.m.

I am going by the MOOG problem solver and using published data.

Dusterbd13
Dusterbd13 Dork
5/10/14 3:39 p.m.

Is there a way to figure out how much to cut for a given lowering?

novaderrik
novaderrik PowerDork
5/10/14 9:17 p.m.
Dusterbd13 wrote: Is there a way to figure out how much to cut for a given lowering?

Zomby Woof covered it a few posts back...

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