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B-mod rear spring longevity question

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Old Mar 31, 2016 | 05:19 PM
  #31  
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Originally Posted by RobRoss
I'm pretty and will verify in the am but 3C34 CC is a B with an overload. When I say B I am referring to the spring rates (320/670). I will verify tho.
I also think you're pretty..In a manly sort of way of course! (you know you can't edit your post now or people will think I'm a freak)
 
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Old Mar 31, 2016 | 05:37 PM
  #32  
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I think Rob is pretty (awesome!) too! Unfortunately I'm repped out for Rob once again, I hope everyone hits him up for all of his spring info help here!
 
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Old Mar 31, 2016 | 05:50 PM
  #33  
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Oooops, that should have read "I'm pretty sure"...thanks guys!
 
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Old Apr 1, 2016 | 07:11 AM
  #34  
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Yes, 3C34 CC is a B spring or P in this case. The rates are as I metioned earlier, 320/670 lbs/in. Enjoy!
 
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Old Apr 1, 2016 | 08:16 AM
  #35  
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Originally Posted by RobRoss
Yes, 3C34 CC is a B spring or P in this case. The rates are as I metioned earlier, 320/670 lbs/in. Enjoy!
what is the "670" number referring to ?
 
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Old Apr 1, 2016 | 08:24 AM
  #36  
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Originally Posted by pirate4x4_camo
what is the "670" number referring to ?
The rate of the secondary. I know we've discussed this before, the drawings for these springs are simple, load vs. deflection, the points are "no load", "transition" (this is where theoretically the primary rolls into the secondary rate) and "max load" where the spring is flat. I say primary rolls into the secondary because if it engaged like it is shown on the plot, it would be harsh and nobody would be happy.

Make sense?
 
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Old Apr 1, 2016 | 08:50 AM
  #37  
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Originally Posted by RobRoss
The rate of the secondary. I know we've discussed this before, the drawings for these springs are simple, load vs. deflection, the points are "no load", "transition" (this is where theoretically the primary rolls into the secondary rate) and "max load" where the spring is flat. I say primary rolls into the secondary because if it engaged like it is shown on the plot, it would be harsh and nobody would be happy.

Make sense?
first off,
I don't want to get this thread off track or confuse the OP, I just like to follow these suspension mod threads and try to understand the engineering behind them

yes I recall our conversation so no need to rehash that. where I am confused or not understanding is exactly which spring in the B pack are giving a 670 rating to ? and maybe more importantly, how far into the total travel does the "secondary" kick in ?
 
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Old Apr 1, 2016 | 09:59 AM
  #38  
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Originally Posted by pirate4x4_camo
first off,
I don't want to get this thread off track or confuse the OP, I just like to follow these suspension mod threads and try to understand the engineering behind them

yes I recall our conversation so no need to rehash that. where I am confused or not understanding is exactly which spring in the B pack are giving a 670 rating to ? and maybe more importantly, how far into the total travel does the "secondary" kick in ?
That spring has roughly 7" of travel, that is from no load to flat. The secondary rolls in around 5" into the full travel, leaving you roughly 2" before the spring is flat. I'll send you my spreadsheet, there is an "auto" tab that highlights where the theoretical secondary engages by load.
 
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Old Apr 1, 2016 | 11:29 AM
  #39  
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Originally Posted by hstechteacher
So after pulling the pack apart and doing the b- mod I only got the truck just to level. So I pulled it back apart and added the excursion half leaf to the bottom. So now I have a slight rake. If the front x codes don't settle out a little I might switch to the 4" rear block.


I am struggling to understand what or I guess WHY you did this ?

what I see is, you took the stock excursion leaf pack with 6 leafs and a anti wrap bar that had a spring rate of 410lbs in

and replaced it with a "B code" 4 leaf pack + over load spring with a rate of 320 lbs in. + overload and then added 2 bottom leafs from your excursion pack + the wrap bar. to end up with what I am guessing is the same 410lb spring rate you started with.

if you wanted a over load spring wouldn't it have just been easier to add one to you stock excursion pack ? or better yet , put on a set of air bags for when you tow, that would allow you to dial the ride height. overload springs are not meant to be apart of your active suspension. they are more of a safety feature to keep vehicles ( usually pickup trucks ) that keep heavenly loaded from allowing a spring to flex past flat and breaking.

it looks to me like you have built a spring pack with the same spring rate you stared with but have likely disabled the anti wrap bar, added an arguably unnessasary overload spring.

anyhow, just trying to understand the purpose of this modification.
 
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Old Apr 1, 2016 | 11:39 AM
  #40  
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Originally Posted by RobRoss
Yes, 3C34 CC is a B spring or P in this case. The rates are as I metioned earlier, 320/670 lbs/in. Enjoy!
I thought they were the same, but thanks for verifying! When you search you find a ton of info on the B's and almost nothing on the P's. What's strange is the junkyard i got these from had 3 trucks all with P's and none with B codes.
 
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Old Apr 1, 2016 | 03:55 PM
  #41  
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Originally Posted by pirate4x4_camo
I am struggling to understand what or I guess WHY you did this ?

what I see is, you took the stock excursion leaf pack with 6 leafs and a anti wrap bar that had a spring rate of 410lbs in

and replaced it with a "B code" 4 leaf pack + over load spring with a rate of 320 lbs in. + overload and then added 2 bottom leafs from your excursion pack + the wrap bar. to end up with what I am guessing is the same 410lb spring rate you started with.

if you wanted a over load spring wouldn't it have just been easier to add one to you stock excursion pack ? or better yet , put on a set of air bags for when you tow, that would allow you to dial the ride height. overload springs are not meant to be apart of your active suspension. they are more of a safety feature to keep vehicles ( usually pickup trucks ) that keep heavenly loaded from allowing a spring to flex past flat and breaking.

it looks to me like you have built a spring pack with the same spring rate you stared with but have likely disabled the anti wrap bar, added an arguably unnessasary overload spring.

anyhow, just trying to understand the purpose of this modification.
The slappers usual purpose in this app is just to add to the static (unloaded) thickness of the pack for it's 7/16 of height gain times how ever many of it's cut up pieces you add. There was no reason to leave it intact other than maybe the OP does not own a metal chop saw
The stock X spring pack is a single stage (constant till flat). The rear of the X must come up 3-4" after the V or X front mod SO the custom B-Mod will net you a 2 stage, stronger, better riding & handling spring (loaded or unloaded) to as well as bring the rear up. The number of springs you add to the pack allows you decide on the amount of rake (or lack thereof) your X now has.
It's a win,win,win


PS: 670LB is Mo bigger & Mo better than 410LB
 
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Old Apr 1, 2016 | 04:45 PM
  #42  
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Originally Posted by harley4jcs
The slappers usual purpose in this app is just to add to the static (unloaded) thickness of the pack for it's 7/16 of height gain times how ever many of it's cut up pieces you add. There was no reason to leave it intact other than maybe the OP does not own a metal chop saw
The stock X spring pack is a single stage (constant till flat). The rear of the X must come up 3-4" after the V or X front mod SO the custom B-Mod will net you a 2 stage, stronger, better riding & handling spring (loaded or unloaded) to as well as bring the rear up. The number of springs you add to the pack allows you decide on the amount of rake (or lack thereof) your X now has.
It's a win,win,win


PS: 670LB is Mo bigger & Mo better than 410LB
Ummm ok
 
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Old Apr 1, 2016 | 08:26 PM
  #43  
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Originally Posted by pirate4x4_camo
Ummm ok
Was that to technical for you PC
I really don't get you confusion ?? Why would you have spent all the time,money, & energy doing a coil conversion up front ?? Other than to improve the X's ride,articulation,turning radius Ect...Ect... So if you needed to raise the rear, You could just get the appropriate block BUT you would not enjoy the advantages (perceived or otherwise) of the B-Mod...
 
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Old Apr 1, 2016 | 09:13 PM
  #44  
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no not to technical for me, just not my style to state somebody's hypothesis is wrong and I didn't have the time to get into it at the time of my post., I'd rather counter with my therory and then discuss the merits of each so everybody can try and gain a better understanding of how and why things work. we can do that here if desired. I see we have a lot of ground to cover
 
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Old Apr 2, 2016 | 09:18 AM
  #45  
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Looks like a good thread to me..Please start by picking my post apart. You might also tell me why FORD added the anti-wrap spring TO ONLY THE X if the rear spring pack is so great for a 3/4 ton truck
 
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