cut springs post?
03-21-01, 08:29 AM
#16
time to cut bait or fish....
Ok, can someone post a pic of the who, what, where and how of cutting a stock SC spring. I figure might as well go ahead and chop it now, since I can always get an aftermarket.
Of course for under 300 bucks is it easier to just order the Eibach or something? I'll do it this weekend if someone can walk me through this & will post the pics.
Check out the car now at: My new toy car
Thanks!!!!
Of course for under 300 bucks is it easier to just order the Eibach or something? I'll do it this weekend if someone can walk me through this & will post the pics.
Check out the car now at: My new toy car
Thanks!!!!
03-21-01, 03:31 PM
#18
nice job!
I like it with the 18's and lowered. What tires are you running? I am looking at epic 18x8 rims with Dunlop 9000's. Yes I need more spring help: lexus@mycrobyte.com thanks!
03-22-01, 11:59 AM
#20
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Re: Cut Springs Post
The idea of cutting the springs is intriguing, cause it seems like a low-buck way to lower the car to whatever point you want (within reason, of course). In response to whether cut springs would be softer or stiffer, I think the latter is true.
The formula for spring force is F = kx, where F is the force the spring exerts on the car (& your butt), k is the spring rate and x is how far the spring compresses. The spring rate k can be expressed as k = JG/L, where J = polar moment of inertia(a property of the spring dependent on the diameter) , G = modulus of rigidity (a property of the spring steel) and L = length of the spring.
Assuming you haven't changed the spring steel properties by grinding or heating the spring, J and G will be constant after the coil-cutting. Therefore, factoring these out, the stiffness or force you feel = x/L.
A cut spring should feel stiffer, which corresponds to the experience of FastSC. As a drastic example, if you cut off half the length of the spring( 1/2L), to compress the spring the same distance, it would take twice the force, or feel twice as stiff. I wonder how the aftermarket springs (Eibach, etc.) differ from stock in diameter, spring rate and # of coils.
That's today's impromptu physics lesson from an admitted non-expert.
The formula for spring force is F = kx, where F is the force the spring exerts on the car (& your butt), k is the spring rate and x is how far the spring compresses. The spring rate k can be expressed as k = JG/L, where J = polar moment of inertia(a property of the spring dependent on the diameter) , G = modulus of rigidity (a property of the spring steel) and L = length of the spring.
Assuming you haven't changed the spring steel properties by grinding or heating the spring, J and G will be constant after the coil-cutting. Therefore, factoring these out, the stiffness or force you feel = x/L.
A cut spring should feel stiffer, which corresponds to the experience of FastSC. As a drastic example, if you cut off half the length of the spring( 1/2L), to compress the spring the same distance, it would take twice the force, or feel twice as stiff. I wonder how the aftermarket springs (Eibach, etc.) differ from stock in diameter, spring rate and # of coils.
That's today's impromptu physics lesson from an admitted non-expert.
03-22-01, 01:42 PM
#21
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I was waiting for someone to post some applied physics equations to this thread.
As for Eibachs, I have seen them, they probably are wound a little tighter/stiffer with higher spring rate, but they are still SHORTER than that of stock springs.
Scot Hail
FastSC300
Ps...thanks for that great insight, I will write that down.
As for Eibachs, I have seen them, they probably are wound a little tighter/stiffer with higher spring rate, but they are still SHORTER than that of stock springs.
Scot Hail
FastSC300
Ps...thanks for that great insight, I will write that down.
03-23-01, 12:26 PM
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Re: Cut Springs Post
Glad to be of help. Hey FastSC, for the benefit of the SC community, could you tell us how many coils you cut off, and /or the finished length of the cut spring? I and others are thinking of trying this option. As you said, Eibachs are shorter than stock, so they could be equivalent to cut-off and repackaged stock springs as far as I know. Thanks.
03-23-01, 01:47 PM
#23
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hey Lexcoupe
On the front I cut about a 1.3/4" off the front and approximately 1" off the rear, I was afraid if I cut them more I would rub on the tires when the springs were compressed hard(285's). I realize now I could have cut a little more(1/2") or so, to set it down a little more. I haven't rub at all with the current hight of the car, and that's even road racing it hard too.
As for the process if you are interested in doing it, just make sure you have some way to cut the spring. The springs are a ***** to cut and no one would cut the spring for me. So I recommend finding someone who will cut them before you take them off. Hacksawing and jigsaw will NOT work on the spring. Ask me how I know:eek:
Here is my number if you have any questions:
832-687-8950
Scot Hail
On the front I cut about a 1.3/4" off the front and approximately 1" off the rear, I was afraid if I cut them more I would rub on the tires when the springs were compressed hard(285's). I realize now I could have cut a little more(1/2") or so, to set it down a little more. I haven't rub at all with the current hight of the car, and that's even road racing it hard too.
As for the process if you are interested in doing it, just make sure you have some way to cut the spring. The springs are a ***** to cut and no one would cut the spring for me. So I recommend finding someone who will cut them before you take them off. Hacksawing and jigsaw will NOT work on the spring. Ask me how I know:eek:
Here is my number if you have any questions:
832-687-8950
Scot Hail
03-23-01, 02:23 PM
#24
Lexus Champion
I stand corrected. It did cause me to do a little additional reading and thinking. A spring is actually a wound torsion bar. The longer the bar the less resistance to a given deflection. Cutting the spring shortens the bar, viola, increased rate.
Scot, how much coil did you cut? 1 coil? 1/2? 1 and 1/2? to get the drop you have?
Your frustration with cutting the springs is due to the hardness of the spring steel (very hard). A cuttoff wheel, plasma cutter or cutting torch are the way to go.
Scot, how much coil did you cut? 1 coil? 1/2? 1 and 1/2? to get the drop you have?
Your frustration with cutting the springs is due to the hardness of the spring steel (very hard). A cuttoff wheel, plasma cutter or cutting torch are the way to go.
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