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Front coil over spring rate? #2547589
09/08/18 01:31 PM
09/08/18 01:31 PM
Joined: Aug 2009
Posts: 235
Central Mississippi
mopar97 Offline OP
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mopar97  Offline OP
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Hello y’all
I am trying to get some weight and adjustability in the front of my B Body drag car. I hope this group can help me.
I have Magnum Force Upper control arms and HDK bolt on upper coil over mounts.
I have lots of shocks set up for coil over mounts from my dirt track days and I want to use those if possible. Easy ups, hold downs, 50-50, etc...I have the QA1 shock specs from HDK so I’m good as far as compressed/ extended lengths so I’m good there, but I do not think 3 in travel is enough for what I want to do. What I I need help/ advise with is a beginning spring rating. I want to know what spring I need to get stock ride height.
Does anyone know a starting weight rating, or a usable calculator? I have done a google search for a conversion calculation but evidently I am not smart enough to use them.

My thoughts are to remove the torsion bars and use the shocks/ coil overs to tune the front rise/ fall rates without changing ride heights. It’s worth a try I think.

Thanks in advance.


Mopar born, Mopar breed, when I die, call me Mopar dead!
Re: Front coil over spring rate? [Re: mopar97] #2547612
09/08/18 02:17 PM
09/08/18 02:17 PM
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Medina, OH
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dart440_72 Offline
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I'm not sure on a chart. I have an HDK k member with Summit brand coil overs. I went with the recommended 450# springs. It's great on the street. I spoke with Denny not to long ago. He recommended 300# springs for my Dart. I haven't put them on yet though. I would give Denny a call and see what he says.

Last edited by dart440_72; 09/08/18 02:17 PM.

72 Dart 500" low deck Indy SR heads. 10.40 @129 best so far
Re: Front coil over spring rate? [Re: dart440_72] #2547676
09/08/18 07:44 PM
09/08/18 07:44 PM
Joined: Aug 2009
Posts: 235
Central Mississippi
mopar97 Offline OP
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Thank you! What part number Summit Coil over?


Mopar born, Mopar breed, when I die, call me Mopar dead!
Re: Front coil over spring rate? [Re: mopar97] #2547677
09/08/18 07:46 PM
09/08/18 07:46 PM
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Porter67 Offline
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What does your front weigh?

Ive #350 on my a body coil over car, #300 was a no go if you still drive on the street and have a pan or trans pan within 2 inches of the road.

Re: Front coil over spring rate? [Re: Porter67] #2547788
09/09/18 01:20 AM
09/09/18 01:20 AM
Joined: Aug 2009
Posts: 235
Central Mississippi
mopar97 Offline OP
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It’s a full body with fiberglass hood, fenders, and bumper but it still has the inner fenders. I don’t think it’s lost over 100 lbs. 350 bottoms out so the 450 May be the way to go?
Thank you


Mopar born, Mopar breed, when I die, call me Mopar dead!
Re: Front coil over spring rate? [Re: mopar97] #2547838
09/09/18 10:35 AM
09/09/18 10:35 AM
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Frostbitefalls MN (Rocky&Bullw...
gregsdart Offline
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I would go with the softest spring that won't coil bind at any part of travel. Then control the rate of rise or compression with shocks.


8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
Re: Front coil over spring rate? [Re: mopar97] #2547839
09/09/18 10:39 AM
09/09/18 10:39 AM
Joined: May 2004
Posts: 12,383
Taxes & Virus's R-US, NY
Dragula Offline
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I run 450 on my Cuda with a MF kit....I switched to Viking shocks with longer extension to allow more travel.


'70 Cuda,...605 EFI Hemi Street Car (6.20 best pass, 1.33 60ft)
https://www.youtube.com/watch?v=WYw6RA-k5Bk (6.25 at 108.75mph from inside car)
https://www.youtube.com/watch?v=3zQEb9uxFng (6.25 at 108mph from outside car)
https://www.youtube.com/watch?v=JCvfzsC4NgM (9.9)

'66 Barracuda AWB Stretched nose Blown 440 Car in build stage

'71 Duster Drag Car 400 Low Deck 512 best 6.002 at 115.44mph
https://www.youtube.com/watch?v=Znuo3jMUXTk
Re: Front coil over spring rate? [Re: mopar97] #2547842
09/09/18 10:51 AM
09/09/18 10:51 AM
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Posts: 314
Medina, OH
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dart440_72 Offline
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Originally Posted By mopar97
Thank you! What part number Summit Coil over?


Mine are part number SUM-G773601


I'm an A body though


72 Dart 500" low deck Indy SR heads. 10.40 @129 best so far
Re: Front coil over spring rate? [Re: Porter67] #2547843
09/09/18 10:52 AM
09/09/18 10:52 AM
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Posts: 314
Medina, OH
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dart440_72 Offline
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Originally Posted By EV2Bird
What does your front weigh?

Ive #350 on my a body coil over car, #300 was a no go if you still drive on the street and have a pan or trans pan within 2 inches of the road.


Thanks for the heads up on this. I have 300# waiting in my garage to put on. Is weight transfer better with the 350#'s


72 Dart 500" low deck Indy SR heads. 10.40 @129 best so far
Re: Front coil over spring rate? [Re: mopar97] #2547888
09/09/18 12:24 PM
09/09/18 12:24 PM
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Charlotte, North Carolina
sgcuda Offline
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The heavier the spring, the stiffer the suspension. Lower pressure springs will give you quicker weight transfer, but will bottom out faster when street driving.


[image][/image]
Re: Front coil over spring rate? [Re: sgcuda] #2547892
09/09/18 12:33 PM
09/09/18 12:33 PM
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Posts: 12,383
Taxes & Virus's R-US, NY
Dragula Offline
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Originally Posted By sgcuda
The heavier the spring, the stiffer the suspension. Lower pressure springs will give you quicker weight transfer, but will bottom out faster when street driving.


Exactly...The spring has to be compressed to store the energy...


'70 Cuda,...605 EFI Hemi Street Car (6.20 best pass, 1.33 60ft)
https://www.youtube.com/watch?v=WYw6RA-k5Bk (6.25 at 108.75mph from inside car)
https://www.youtube.com/watch?v=3zQEb9uxFng (6.25 at 108mph from outside car)
https://www.youtube.com/watch?v=JCvfzsC4NgM (9.9)

'66 Barracuda AWB Stretched nose Blown 440 Car in build stage

'71 Duster Drag Car 400 Low Deck 512 best 6.002 at 115.44mph
https://www.youtube.com/watch?v=Znuo3jMUXTk
Re: Front coil over spring rate? [Re: Dragula] #2547961
09/09/18 03:05 PM
09/09/18 03:05 PM
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Posts: 11,521
Fulton County, PA
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CMcAllister Offline
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Fulton County, PA
Originally Posted By Dragula
Originally Posted By sgcuda
The heavier the spring, the stiffer the suspension. Lower pressure springs will give you quicker weight transfer, but will bottom out faster when street driving.


Exactly...The spring has to be compressed to store the energy...


True. Lighter springs will have to be compressed more to support a given amount of weight at a given ride height. This makes the suspension more "lively", stores energy in the spring and helps with separation. A good DA shock is needed to control the suspension when going this route, front or rear.


If the results don't match the theory, change the theory.
Re: Front coil over spring rate? [Re: sgcuda] #2548148
09/09/18 10:54 PM
09/09/18 10:54 PM
Joined: Aug 2009
Posts: 235
Central Mississippi
mopar97 Offline OP
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Thanx for the assistance..


Mopar born, Mopar breed, when I die, call me Mopar dead!






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