O 16581 72452 5

This is my temporary solution to my problem. I've an AutoX event coming up the 29th of this month, i need to swap on my suspension from my GSL-SE to my AE86 due to the aftermarket rims and tires being the incorrect offset and rubbing the strut (i can't compete with 165 dry rotted "General" tires). In my swap, i want to drop the car as low as possible before the event by cutting the springs mainly because i won't have time to wait for springs to come in before the event. I may be cutting as much as two coils off, i realize this will make the springs stiffer (which i want), but it will make the springs much weaker (easiest way i can think of it is like taking support beams out of a roof). My 86 is roughly 400lbs lighter than my GSL-SE, i would think i should be safe only driving hard on cut springs for a day and getting real springs ordered afterwards. Any input on this?

reza

I don't think cutting the spring will change the spring rate "stiffer". The heat applied to the metal of spring may change the rate however...

rfreeman27

iTrader: (5)

Yeah it wolnt make it stiffer. you are going to bottom out everywhere slamming the car, and using soft stock springs.

O 16581 72452 5

It really has nothing to do with spring rates, it doesn't change them at all. The car will have a lower center of gravity however causing it to lean less in the turns. That makes them "stiffer" in my opinion.

DamonB

One of the things that effects spring rate is how many coils are within a given distance; fewer coils within the same length of spring gives you a stiffer spring. Since most springs have the last couple coils wound closer together your spring will get stiffer when you cut those off.

IMO there is never an excuse for cutting springs. Aftermarket springs are cheap and readily available. If you need them soon have them shipped FedEx.

O 16581 72452 5

I didn't think of that, but to end the long debate of cutting springs ******* up spring rates, as long as the coils are the same distance, cutting them will do nothing to spring rates. The suspension will just simply have less area to travel and the car will handle slightly better due to a lower center of gravity.

True that there really is no excuse for cutting springs, but i know if i ordered springs through a company there would not arrive here in time.

I have to swap cups from my AE86 to my Rx-7s struts, i figure while the coils are out i might as well chop them.

SleepR1

There's an algebraic equation that descibes spring rates, and in fact the number of coils in a spring DOES affect spring rate--the fewer the number of coils, the higher the spring rate; conversely the higher the number of coils, the softer the spring rate. Perhaps Clayne can chime in, and put up the physics formula LOL (I smell another debate brewing)

DamonB

A coil spring is just a torsion bar wrapped into a coil. If wire diameter, free length and spring diameter stays the same and you add more coils then the torsion bar just became longer, so your spring will get softer. If you were to subtract coils for a given free length the spring will get firmer.

As long as you picture coil springs as torsion bars it's easy to visualize what properties are effected with changes.

Make spring firmer:
Fatter wire (thicker bar)
Fewer coils (shorter bar)
Smaller spring diameter (shorter bar)

Make spring softer:
Thinner wire (thinner bar)
More coils (longer bar)
Larger spring diameter (longer bar)

Progressive springs can be made (cheaply) by altering the distance between each successive coil and/or varying the spring diameter along its length, or they can be made (very expensively) by grinding the spring wire into a cone shape so it gradually gets thinner along its length but winding it with even spacing and diameter.

O 16581 72452 5

Yeah, nevermind.

SleepR1

Well, I guess that's the way to end the debate LOL

Redwood

The advantage to cutting springs, IMO, is that a person can remove the "progressive" coils at the ends of the spring. Done correctly, this can lead to a very linear (and therefore predictable) spring. However, I too cannot condone this and leave it up to those who know exactly what they are doing as it seems it would be difficult to get it to seat correctly and all that.

I have heard of it being done by experienced autocrossers, but in the same sentence I was told to never do it to a car that will see a mile on the street (street contours/bumps are too unpredictable). Find a civic with cut springs and watch it drive on the freeway, it's quite humorous to see the counter-productive/intuitive movement of the wheel.

Redwood

Spool Up

F=kx

O 16581 72452 5

Getting them to seat correctly doesn't seem it'll be a problem, my cups aren't contoured, merely a flat surface.