cutting my springs

[rps13kid]

ok how many coils can i cut so it will not ride so hard and how much will it drop if i cut 1 1/2 or 1 coils????? anybody do it ??

[PabloHoney]

Are you dumb??? Cutting your springs is about as ghetto as it gets. It's not gonna change how the car rides for one. The stock springs have a linear spring rate, not progressive. The only thing you will change is the ride height. Just buy some Eibach springs. DO NOT CUT YOUR SPRINGS!

[rps13kid]

yea i am getting some tein springs next month and i am bored rite now and wanna do something so i felt like doing my springs so i can get the bolts off easier when i do my other springs,i know it is getto but if you cut like 1 coil it dont ride that bad i guess,i just want the drop,...

[Yoshi]

Originally posted by rps13kid
yea i am getting some tein springs next month and i am bored rite now and wanna do something so i felt like doing my springs so i can get the bolts off easier when i do my other springs,i know it is getto but if you cut like 1 coil it dont ride that bad i guess,i just want the drop,...

Get the bolts off easier? so u plan to cut the springs while under load? so is self mutilation the objective here or what?

[THX1138]

If you're getting new springs in a month and you're bored right now, there are plenty of better things you can do than cut your stock springs. Change your oil, put in some better brake pads, read a book, bake a cake, take your girlfriend to the movies, or just take a nap, but don't cut your springs *ESPECIALLY* under load.

[Natty]

Originally posted by Yoshi
Get the bolts off easier? so u plan to cut the springs while under load? so is self mutilation the objective here or what?

Stop giving him ideas and nature will take its course
Jeff

[Chernobyl]

Ok, don't kill me for this, but I'd really like to see some proof that cutting springs screws up the rates. By shortening a spring, you raise the rate, and production springs can't be THAT far off that cutting exactly the same amount off each one will throw off the whole balance of the car. I've had cut springs on another car of mine back in the day, and it was done out of necessity (using 280z struts on a 240z, different perch heights), and of course the ride was stiff, but with good tokicos it didnt bounce and was actually quite firm riding and looked great. So what I'd really like to see is some spring rate tests on a set of cut springs or something that PROVES that it screws things up.

By the way, my current s14 has RSR springs. However nice the 240z rode with the cut springs, I'm not going to jimmyrig anything on this car..

[russian]

dude what the ****? you gonna replace the shocks/struts too in a month? if you cut springs it will blow your suspension prety quick. and cutting under car load is waaay silly. dont do what accord ownerz around my town do, they bounce all over the place. **** dat!

[Dousan_PG]

i thought i replied this......hrm.

its ok to cut your springs, just depends HOW MUCh you cut off.
i know 2 people who use cut springs.

one of them he cut at least 5 sets before he got it 'perfect'

people automatically associate cut springs with crap ride. its true because most people just chop it and do it incorrectly


personally i would NOT suggest it. just chill for a month and hang tight.

[andrave]

I'd say you could remove at least 5 or 6 turns off the front, even more out back.
It would probably help your ride if you were to actually weld the spring perches together, the top and bottom ones. that would mean no coil springs, and like... a foot of drop. as we know, a stiff suspension is a high performing one, so no springs at all is the best possible sporting suspension.

[SaintlyCharBoy]

a spring can be cut right, and still work fine - sometimes better (esp. with progressives) but often when someone cuts springs he just do more harm than good

1 he/she/it cuts away too mush of the spring - duh

2 aforementoined body cuts the spring perpendicular to the angle of the winding, rather than the central axis of the spring, so it will no longer seat -> bad

3 doofus goes nuts with a hacksaw, rotary tool, or torch to cut the springs and beats the hell out of the temper, making the spring no longer have the sproing

please please please just wait a month

the tein springs i installed were short enough that they didn't need a compressor - plenty worth the wait

[Tubed4evr]

Alright if you cut a linear spring then the spring rate will not change (take it from a mechanical engineer). The harm in doing this is that you are taking away from the available suspension travel. That's perfectly fine until you hit a bump and "ask" the suspension to travel farther than its "allowed" to. This is when you "bottom out" the suspension and it becomes worthless and your ride quality ( along with handling ability in most cases) goes to caca. Cutting springs is generally not a good idea and can be very dangerous if not done properly.

Ryan



P.S. I can supply equations for anyone who is interested in the first statement.

[rps13kid]

ok heres what happend i did it and it dropped it bout an 1/2 in and yea for all the work it was not worth it so i am ordering the springs and struts tommrow,, it rides the same as b4 too but yea i think it is not worht it....what a way to spend a night so yea
thanks for your help.

[240silvia]

NO, no one has done it b/c number 1, it messed up your stock suspension, and 2 it's just flat out cheap. Come on Bro, spend some money.

[s13fastback]

just wait a month .... for your real springs

[Chernobyl]

Originally posted by Tubed4evr
Alright if you cut a linear spring then the spring rate will not change (take it from a mechanical engineer). I can supply equations for anyone who is interested in the first statement.

You are right, maybe I should check my physics books more often. F(spring)=kx, with K being the constant and x the distance the spring is compressed or stretched. But I can't find anything that tells me how the value of the constant is calculated, into which I still believe the length of the spring comes into play. If you know an equation or have some chart for this, I'd like to see it.

Edit: I think about it this way: a spring with say 5 coils will distribute a force applied to it onto all 5 coils. One with 4 coils distirbutes the load across 4, and thus each coil will exert a higher force back... Hmm, maybe I should just go in the garage and cut a spring and measure, but I have finals in an hour and don't have time. Anyone experimented with this in controlled conditions before?

Take a brick or something, weigh it, place it on the spring, and measure the amount of deflection in the spring.

K=(m*g)/X where deflection is X, m is mass (kg) and g is gravitational constant (9.81)

then cut a coil off the spring and use the same brick, and measure deflection again. calculate K, the spring rate again and compare... any changes?

[hookedup240]

Originally posted by rps13kid
ok heres what happend i did it and it dropped it bout an 1/2 in and yea for all the work it was not worth it so i am ordering the springs and struts tommrow,, it rides the same as b4 too but yea i think it is not worht it....what a way to spend a night so yea
thanks for your help.

why did you bother posting and asking if you did it anyway?

[rps13kid]

Originally posted by hookedup240
why did you bother posting and asking if you did it anyway?

ok i asked if anybody did it.because i was gonna do it

[AceInHole]

Originally posted by Chernobyl
Edit: I think about it this way: a spring with say 5 coils will distribute a force applied to it onto all 5 coils. One with 4 coils distirbutes the load across 4, and thus each coil will exert a higher force back... Hmm, maybe I should just go in the garage and cut a spring and measure, but I have finals in an hour and don't have time. Anyone experimented with this in controlled conditions before?

Ok. Take it from another mechanical engineer. You're correct. Cutting 1 coil off a 5 coil spring raises the rate something like ... 5/4's. Pretty much for the exact reasons you said. Distributing load and such. Wow. Making sense is cool.

from a quick GOOGLE search:
http://www.masterspring.com/library/fr_eng_tips.htm

Adding a coil weakens the rate. Removing a coil strengthens the rate.

P.S. I have half a coil cut off my Sportlines. If handling is crapped out because of it.... I must be 1 very good driver.

[Chernobyl]

Thanks Ace, that's what I was getting at. I spent all day pondering this, and came to the conclusion I stated. I was sure the unladen spring length had an effect on spring rate.

My only beef is: why do you call yourselves "mechanical engineers"? Are you actally certified and working for a design corporation, or are you still in college? Sorry if I'm wrong, but I'm assuming both of you are still only ME students, not actual ME's. If you are actually an ME and not a student, disregard this last paragraph...

BTW, I just finished my 2nd year of my ME major.

[AceInHole]

Originally posted by Chernobyl
My only beef is: why do you call yourselves "mechanical engineers"? Are you actally certified and working for a design corporation, or are you still in college? Sorry if I'm wrong, but I'm assuming both of you are still only ME students, not actual ME's. If you are actually an ME and not a student, disregard this last paragraph...

Heh... i'm an 8th semester ME student at UConn. But, does interning count???

BTW, I just finished my 2nd year of my ME major.

Good luck. Doesn't get any easier IMO.

[Chernobyl]

Eh, I'm just a humble person at heart. Its just my peeve when kids at school say they are MEs while still in college... graduate first. Nothing personal against you obviously.

[AceInHole]

Originally posted by Tubed4evr
P.S. I can supply equations for anyone who is interested in the first statement.

I'd like some equations to back up your:

Alright if you cut a linear spring then the spring rate will not change (take it from a mechanical engineer).

Because... both a Mech Eng undergrad student (ok. I typed the extra letters) and a Physics grad student (a very notable one in the 240sx community) disagree with your equations.