Does cutting springs change the spring rate.
Thread Starter
Race Director
Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
Does cutting springs change the spring rate.
Just for something to do Friday afternoon and for curiousity I took a brand new factory 454 air conditioning spring and run it in a spring checker. This machine is $80,000 and is extremely accurate. Anyway the spring checked out at 330 pounds per inch. I then cut out exactly 1 turn with a chop saw and ran it again. This time I got 360 pounds per inch. Up 30 pounds per inch with 1 cut coil.
I am still considering installing the 460 pound springs but worry about lowering the car. With tall soft morosso springs my ride height is a little high but my deep sump oil pan clears the road by only about 3 or 4 inches and I am worried that the 460 will lower the car too much.
I also read that the 550's are just cut 460 but that would be too much of a jump from just cutting.
I would cut more out of the factory springs but I could still use them if I wanted with just one coil cut out.
I am still considering installing the 460 pound springs but worry about lowering the car. With tall soft morosso springs my ride height is a little high but my deep sump oil pan clears the road by only about 3 or 4 inches and I am worried that the 460 will lower the car too much.
I also read that the 550's are just cut 460 but that would be too much of a jump from just cutting.
I would cut more out of the factory springs but I could still use them if I wanted with just one coil cut out.
Drifting
Joined: Jul 2000
Posts: 1,266
Likes: 0
From: Allen, TX, USA
Re: Does cutting springs change the spring rate. (norvalwilhelm)
HI Norval;
As I remember, the constant depends on the number of coils, the diameter
(probably radius) of the coil and the diameter of the steel.
I don't have the formula on me, but that sounds to be about what I calculate when I was cutting springs. I just didn't know the original spring constant
to double check the figures. 10% sounds about right.
Have any of the other springs to check their supposed spring constant?
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
Re: Does cutting springs change the spring rate. (norvalwilhelm)
Norval - the 460/550 spring has much thicker coils and I believe they're spaced closer together. Hence, chopping them has a greater effect.
The 550 is 1.25" shorter than the 460. All other measurements (ID, OD, and coil diameter) are the same.
-Steve
[Modified by Pacin'California, 8:23 PM 3/22/2003]
The 550 is 1.25" shorter than the 460. All other measurements (ID, OD, and coil diameter) are the same.
-Steve
[Modified by Pacin'California, 8:23 PM 3/22/2003]
Abby Normal
Joined: Dec 2001
Posts: 53,461
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From: Press "2" for English
Re: Does cutting springs change the spring rate. (norvalwilhelm)
hey norval, saw your latest sig pic in another thread (that thing is crazy!).
anyway, i replaced my OEM springs with the VB 460 springs about two years ago. at that time i didn't notice any difference in ride height. now i don't know if that just means the originals were worn out and sagging at 150k or not. since then i've cut 1/2 a coil from the 460s and could not tell a difference in ride (ahem) 'quality'. don't know how they would affect that monster you have in your car though.
anyway, i replaced my OEM springs with the VB 460 springs about two years ago. at that time i didn't notice any difference in ride height. now i don't know if that just means the originals were worn out and sagging at 150k or not. since then i've cut 1/2 a coil from the 460s and could not tell a difference in ride (ahem) 'quality'. don't know how they would affect that monster you have in your car though.
Burning Brakes
Joined: Aug 2002
Posts: 1,090
Likes: 8
From: Indianapolis Indiana
Re: Does cutting springs change the spring rate. (norvalwilhelm)
I installed 460# springs on my stock small block last year and it raised the front at least an inch or 2. Wished I had cut them.
Le Mans Master
Joined: Mar 1999
Posts: 6,744
Likes: 1
From: delmont pa
Cruise-In I Veteran
Cruise-In II Veteran
Re: Does cutting springs change the spring rate. (norvalwilhelm)
a coil spring is a torsion bar wound in a circle. a 300 PPI spring with 10 turns should gain 30# if you cut off 1 full turn. this is not true with progressive wound springs
Melting Slicks
Joined: Jun 2002
Posts: 2,844
Likes: 99
From: Orrtanna Pa.
Re: Does cutting springs change the spring rate. (norvalwilhelm)
I believe you answered your own question about cutting the springs,and rate.
I run the VB 550's and a Moroso 7 qt. kickout pan,and have concerns when driving over road kills,but have no concern about bottoming out the pan due to rough roads. The springs are so stiff,when the roads get rough,you are forced to slow down.Failure to do so would result in your head hitting the glass roof panel.Don't ask how I know this. :chevy
I run the VB 550's and a Moroso 7 qt. kickout pan,and have concerns when driving over road kills,but have no concern about bottoming out the pan due to rough roads. The springs are so stiff,when the roads get rough,you are forced to slow down.Failure to do so would result in your head hitting the glass roof panel.Don't ask how I know this. :chevy
Race Director
Joined: Sep 1999
Posts: 11,361
Likes: 383
From: Plano TX
Re: Does cutting springs change the spring rate. (The Money Pit)
The springs are so stiff,when the roads get rough,you are forced to slow down.Failure to do so would result in your head hitting the glass roof panel.Don't ask how I know this. :chevy
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Thread Starter
Race Director
Joined: Nov 2000
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From: Waterloo ontario Canada
Re: Does cutting springs change the spring rate. (zwede)
zwede I agree with the soft springs. I keep telling myself I should go with heavier springs but I just can't bring myself to do it. I don't want to pound my front end over railway tracks or anything else but I don't like the way the car rises on launch. The front end is like a boat comming out of the water. I would rather stay flat. I don't mind the mustang with it's wheels up launch but not the vet.
My stock car friend Roger also advises agains hard springs to save the front end. I was going to order the 460's tomorrow but have already chickened out.
Clutchdust. By now I thought everyone would now my car. This is I think the 4th season comming up that I ran the blower motor. It is a 460 with a 8-71 blower running 15% overdriven for 12 psi of boost from idle on up, 2 850 double pumper carbs, full roller motor and a very good set of heads.
I also have a full 3 inch exhaust and this summer same as last a TKO. With the same motor and slicks I broke 3 700R's and 4 torque converters in one summer. All I did was install and pull transmissions and take them back for warranty. Warranty was $500 each time. I gave up the slicks and went standard.
The car slowed down but the driving fun went way up.
My stock car friend Roger also advises agains hard springs to save the front end. I was going to order the 460's tomorrow but have already chickened out.
Clutchdust. By now I thought everyone would now my car. This is I think the 4th season comming up that I ran the blower motor. It is a 460 with a 8-71 blower running 15% overdriven for 12 psi of boost from idle on up, 2 850 double pumper carbs, full roller motor and a very good set of heads.
I also have a full 3 inch exhaust and this summer same as last a TKO. With the same motor and slicks I broke 3 700R's and 4 torque converters in one summer. All I did was install and pull transmissions and take them back for warranty. Warranty was $500 each time. I gave up the slicks and went standard.
The car slowed down but the driving fun went way up.
Drifting
Joined: Feb 2002
Posts: 1,987
Likes: 3
From: Manchester, Dead Center in the Middle of TN 25 miles to Jack Daniels,10 miles to Geo Dickle, and .8 mile from the Liquor Store at I-24 Exit 114
St. Jude Donor '05
Re: Does cutting springs change the spring rate. (clutchdust)
I replaced my OEM springs with the VB 460 springs about two years ago. at that time i didn't notice any difference in ride height. now i don't know if that just means the originals were worn out and sagging at 150k or not. since then i've cut 1/2 a coil from the 460s and could not tell a difference in ride (ahem) 'quality'. don't know how they would affect that monster you have in your car though.
Le Mans Master
Joined: Jun 2002
Posts: 8,339
Likes: 24
From: I can walk to MA
Re: Does cutting springs change the spring rate. (zwede)
I agree with zwede, too. I have read various suspension discussions that
address this very issue: soft springs and a mother of a sway bar configuration,
preferrably with solid rod ends. I wouldn't go that far, but a big bar and poly
bushings will do a lot. The basic idea: keep all 4 wheels planted on the pavement.
Norval, have you looked into adjustable drag shocks ? I recall seeing some
that could be dialed in from 10/90 - 50/50 - 90/10. Not sure where I saw 'em.
[Modified by NHvette, 11:37 PM 3/23/2003]
address this very issue: soft springs and a mother of a sway bar configuration,
preferrably with solid rod ends. I wouldn't go that far, but a big bar and poly
bushings will do a lot. The basic idea: keep all 4 wheels planted on the pavement.
Norval, have you looked into adjustable drag shocks ? I recall seeing some
that could be dialed in from 10/90 - 50/50 - 90/10. Not sure where I saw 'em.
[Modified by NHvette, 11:37 PM 3/23/2003]
