Anyone cut stock springs?

[JDM-P5]

JDM-P5, that is about where I want it. It is almost too low. My springs are only a 1" dop in the rear and 1.2" in the front.

Didn't I tell you to buy Tein springs in the first place...?

Goodness gracious, you are like my subordinates that work for me...after the fact, they are like oooooh, now I see what you mean.(spank)

 

[cbrcrx]

Didn't I tell you to buy Tein springs in the first place...?

Goodness gracious, you are like my subordinates that work for me...after the fact, they are like oooooh, now I see what you mean.(spank)

I'm really talking about the front compared to the back, not how low it is. Yours looks more even than NCZ13s. It's hard to tell with everybody having different size wheels. I think mine will look a little lower than NCZ13s because it has 17s instead of 16s.

 

[Billy_08MS3]

Damn, I read 9 pages hoping for cut springs and he got Eibach's? Lame...

 

[cbrcrx]

Damn, I read 9 pages hoping for cut springs and he got Eibach's? Lame...

An apostrophe before the s shows posession. You are meaning plural noun. Anyway, I still might have to cut a half of a coil if the front isn't low enough.

 

[Billy_08MS3]

Who gives a s***, cut your ******* springs.

 

[cbrcrx]

Who gives a s***, cut your ******* springs.

Pleasant.

 

[lanny709]

Yeah, to tell you the truth after reading all of this I was kinda pumped for some cut spring pics... Slightly disappointed now

 

[alexelie]

i saw someone who cut his springs on his p5 and i think i was too low...you have to make sure you cut them right in other case you are in some trouble. anyways, springs are not so expensive...

 

[Billy_08MS3]

I just don't understand why you would buy the Eibach springs and cut them when you said cutting the stockers would be so great. Please explain...

 

[gottacatchup]

Man, all you guys and your "scientific" explanations make me laugh...

I would like to start by saying I don't suggest cutting springs to anyone, but IF done correctly, the only adverse effect will be the greater potential of hitting the bump stops.

Now, if I have a spring, doesn't have to be an automotive spring, and cut it in half, does it's spring coefficient change? If it is a linear spring, then no, it does not. I have not altered any of the material properties of the spring in any way (heat treating however, does have an impact and I highly suggest against doing this). Now with progressive springs it's a little different. Progessive springrates mean that as the spring compresses the coefficient (and therefore transferred force) increases. Instead of the force being a direct correlation (F=kx), the spring coefficient, k is now a function of x (F=k(x)*x). So in this case, cutting the spring will cause the rate to change. Cut off too much and the ride becomes bouncy. Cut off just a little and it will only be a little stiffer than stock. It's all about moderation. Too many people are are used to seeing guys cut off WAY too much and killing functionality. Truth be told, if done accurately and carefully, cutting the stock springs will result in a similar springrate and ride height as some of the progressive springrated aftermarket springs out there. I'm not saying you get the same quality, but the end result will be similar, especially with aftermarket shocks.

Woah, timeout. Sorry to bring this back up but I completely missed this post originally. And I'm sorry to say that you're completely and totally wrong in this.

Sure when you have a linear spring the k is constant and the force depends on the displacement of the spring. However the length of the spring plays a direct roll in the value of k.

k is calculated using an equation that relates the modulus of regidity of the material, the diameter of the spring wire, the overall diameter of the coil, and the number of coils in the spring.

By cutting off coils you do change the spring rate.

If you don't believe me you can look at the equation yourself here:
http://www.efunda.com/designstandards/springs/calc_comp_designer_eqn.cfm

 

[red95_240sx]

what if he cuts a progressive spring?

 

[Billy_08MS3]

what if he cuts a progressive spring?

Probably just change the rate range?

The Pro Kit is progressive, let him cut them and tell us how it changes the loading of the springs...

 

[red95_240sx]

most progressive springs have coils that bind together when the car is on the ground.

 

[lil_red_wagon]

most progressive springs have coils that bind together when the car is on the ground.

yeah, when you cut a progressive spring, you are taking away the most firm and rigid part of the spring. that means that you are negatively affecting the spring rating.

 

[slideshow240]

just dont cut springs

/thread

 

[JDM-P5]

Well he got the springs.

Just waiting for the pics now.

 

[DuRWooD]

Cut mine for fun. Liked the ride, left it. Coilovers coming though. Bimmer rides on eibachs with bilsteins.

 

[red95_240sx]

the most firm coils are in the middle. those lil coils at the bottom can almost be compressed by hand, they r there for comfort i believe right?

 

[JDM-P5]

Sure a slammed car looks great...but its all about the end product...which is the ride and the performance.

 

[gottacatchup]

what if he cuts a progressive spring?

Now I'm not as well versed in exactly how progressive rate springs work but here's what I believe happens.

If you look at the equation I linked to in my other post it talks about the number of coils in a spring being a factor. To be more specific it's the number of active coils that determine the spring constant. As a progressive spring compresses those little coils at the bottom fully compress so that they are touching. When this happens they are no longer active coils. So by removing those coils the spring rate increases.

If you were to cut off those smaller, bottom coils you'll reduce or possibly eliminate the "low" spring-rate zone making the car transition to the higher spring-rate at lower cornering forces.