front coil over spring rate
#2492388
05/05/18 12:27 PM
05/05/18 12:27 PM
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Joined: Aug 2016
Posts: 20 ca
sergio
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OP
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Joined: Aug 2016
Posts: 20
ca
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Need to order the front coil springs .Car is 4 link a arm fully loaded 2650lb 50/50. Viking dual adj. 110 lb, rear. The car has 450 lb 7 1nch now but they require a lot of spring compression to achieve proper ride height,plus they are junk.I know what the manufactures recommend.Those that have experience ,would you use 475/500 7 inch or a 400425/ 8inch spring .This will be a box car maybe ss/super gas, This will not be a very fast car,i am not concerned with travel, mostly consistency. Its a small block 580ish hp,glide,as big a tire as I want ,currently 14x32 with 4.88 dana . What are you guys using,hoping Dave Hall or Al or Keith Richards will chime in. Car is a 71 cuda with 113 wheelbase
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Re: front coil over spring rate
[Re: sergio]
#2492422
05/05/18 01:40 PM
05/05/18 01:40 PM
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Joined: Dec 2005
Posts: 11,551 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,551
Fulton County, PA
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450 sounds like a lot for that car on a typical Mustang II style A arm. On the front, you usually want to use a lighter spring compressed some and use the shock to control it. On a deal like yours, I've tried tying them down to get a light and it made the car junk. You need some front movement to get some pitch rotation and an aggressive 4 link set up to make it go red.
Who's shocks are on the front? What is the installed C-C on the front shock? Is that 2650 with driver? Not all A arm setups are the same. Take two measurements - lower control arm pivot to lower shock mount and lower control arm pivot to center of lower ball joint.
What gear set is in the trans?
If the results don't match the theory, change the theory.
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Re: front coil over spring rate
[Re: sergio]
#2492500
05/05/18 05:47 PM
05/05/18 05:47 PM
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Joined: Dec 2005
Posts: 11,551 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,551
Fulton County, PA
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Your car sounds just about identical to one I'm working on right now, except for the 4 link and this one is a few percentage points lighter on the nose. That and it has a 900 horse SB2 in it. We're putting Strange DAs with 8" 350# springs on the front and 125# springs on the rear to try to calm the ladder bar suspension down. I'd like to have the front shocks in at about 9.75" with the spring compressed 2.5" or so. Front spring rates aren't as critical as rears, but I like to have them compressed a bit to make the front end a little more "lively" and control it with the shock. I'm going to put this thing together and on scales in the morning to see if my results match my arithmetic.
That 8" spring is compressed 1/2" when it's on that short shock with the spring seat all the way down. Then compress it another 1 1/2" to get the shock in at the correct length. My arithmetic says a 400 spring will be compressed ~2" at ride height. A 350 spring will need to be compressed ~2.5".
You mean a 1.90 in a Glide?
If the results don't match the theory, change the theory.
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Re: front coil over spring rate
[Re: sergio]
#2493404
05/07/18 11:06 PM
05/07/18 11:06 PM
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Joined: Dec 2005
Posts: 11,551 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,551
Fulton County, PA
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Spent part of the day setting up a car very close to yours weight and front suspension wise using 8" 350 springs. I expect the 375s will be way heavy for your situation. 350s are compressed very little at the shock length we are using, but should be fine on this car at the power level he has.
If the results don't match the theory, change the theory.
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Re: front coil over spring rate
[Re: sergio]
#2493671
05/08/18 03:51 PM
05/08/18 03:51 PM
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Joined: Dec 2005
Posts: 11,551 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,551
Fulton County, PA
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I doubt you can get the shock closed up to 10" with a 350# at your front corner weight. Maybe, but you won't have them compressed to store any energy to help rotate the car.
Last edited by CMcAllister; 05/08/18 03:53 PM.
If the results don't match the theory, change the theory.
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