"Gonna do it right...maybe!!??" Fuller's new XJ build!!!

wait a minute..so it takes 186 lbs to compress the spring 1 inch...so I need the spring to compress roughly 4" or so to work in the rear (keep my ride height at what it is now...so that would require 744 lbs to compress the spring 4"????? am I following this right
 
This is my full droop and at ride height...am I just being too obsessed now (doesn't look as compressed as I was thinking maybe?)
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Loganwayne said:
Shit our metal suppliers are giving us price increases every 15 days


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Well damn...my last company dealt with Delaware Valley Steel, and (at that time) I don't recall constant increases, definitely weren't increases often in the employee sale/scrap side of things, but they may have been pitching us a deal too. But that still brings the suck nonetheless...
 
Just fucking run it and find out. You really need a taller free height spring so it'll stay seated at full droop, but give it a shot.

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marty79 said:
This is my full droop and at ride height...am I just being too obsessed now (doesn't look as compressed as I was thinking maybe?)
View attachment 265303 View attachment 265304
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Don't know what you mean by "doesn't look as compressed," but it looks to me that your shocks are acting as your limiting straps while checking full droop. I'd disconnect those to check for binding. Checking travel for full bump/droop includes removing springs and shocks, and checking travel, both compressed and drooped, and articulating one side then the other. If your shocks are your limiters, I'd add a limiting strap in at each corner so you don't kill your shocks the first time out.

EDIT:

Chris_Keziah said:
Just fucking run it and find out. You really need a taller free height spring so it'll stay seated at full droop, but give it a shot.

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What he said.
 
so I just calculated all the cage and it's materials....292lbs WTH am I missing something or does this sound right...why was I expecting this number to be like 500lb or more like 6-700 the way everyone has made it sound. 300 lbs just doesn't justify enough for the amount of steel and mind your this is not just the cage but the rockers too. (not the boad sides and frame plating, didn't count that since that sits midline and would seem not to affect it as much I would think
 
Chris_Keziah said:
Just fucking run it and find out. You really need a taller free height spring so it'll stay seated at full droop, but give it a shot.

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see what I'm doing now lol, I'm getting all paranoid and meticulous about stupid crap wondering if it's gonna "hold up" but I'm being cautious cause this is the last time I'm touching this suspension since it's my ideal size and setup I want.
Good Point though, just chill run it and see how it does!
 
Scooter402 said:
but it looks to me that your shocks are acting as your limiting straps while checking full droop.
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for now, will make some limiting straps too. Hoping to find/buy longer travel shocks as the 9" droop isn't enough for what I was wanting.
 
Scooter402 said:
Checking travel for full bump/droop includes removing springs and shocks, and checking travel, both compressed and drooped, and articulating one side then the other
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done it already when I first mounted springs, all was great. was really amazing how "free" moving the 4 link is/was (maybe cause of the Heims since I've always had bushings)
 
marty79 said:
This is my full droop and at ride height...am I just being too obsessed now (doesn't look as compressed as I was thinking maybe?)
View attachment 265303 View attachment 265304
Click to expand...

Looking at both pictures, and the position of the shock, my guess is you need more up travel to make the suspension work correctly. Maybe find a taller free height spring (as suggested) and move the upper shock mount higher. From what I have seen suspension that is closer to 50/50 up and down travel works better. Just a guess though....
 
marty79 said:
so I just calculated all the cage and it's materials....292lbs WTH am I missing something or does this sound right...why was I expecting this number to be like 500lb or more like 6-700 the way everyone has made it sound. 300 lbs just doesn't justify enough for the amount of steel and mind your this is not just the cage but the rockers too. (not the boad sides and frame plating, didn't count that since that sits midline and would seem not to affect it as much I would think
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You sure you didn't forget to carry the 2 or something? That sounds awful light... Post up some dimensions of the materials...I need something to do lol
marty79 said:
for now, will make some limiting straps too. Hoping to find/buy longer travel shocks as the 9" droop isn't enough for what I was wanting.
Click to expand...
Yeah, 9" shocks definitely aren't enough for a suspension like that. I know you probably don't want to get shocks twice, but I found some el-cheapo's on eBay once upon a time that were long. IIRC they had something like 13-14" travel. Mind you, they were CHEAP...but they worked. Unless you want to save your nickels and dimes for some good ones, that'd probably be the better route.
marty79 said:
done it already when I first mounted springs, all was great. was really amazing how "free" moving the 4 link is/was (maybe cause of the Heims since I've always had bushings)
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Oh, my bad...I was assuming (emphasis on the first syllable, on my part :rolleyes:) that you were checking for binding. Nevermind, carry on.
 
junkxj said:
Looking at both pictures, and the position of the shock, my guess is you need more up travel to make the suspension work correctly. Maybe find a taller free height spring (as suggested) and move the upper shock mount higher. From what I have seen suspension that is closer to 50/50 up and down travel works better. Just a guess though....
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i wanted that but unfortunately my lower links will only go up 3.75" before hitting frame which is fine with me. So I plan on getting shocks eventually and springs to have 3.5" up travel and 12-14 down, that's my goal.
 
marty79 said:
wait a minute..so it takes 186 lbs to compress the spring 1 inch...so I need the spring to compress roughly 4" or so to work in the rear (keep my ride height at what it is now...so that would require 744 lbs to compress the spring 4"????? am I following this right
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Assuming a linear spring rate - yes.

EDIT:

But, if those springs have been cut (I didn't study the pics), the spring rate is higher than 186 lb/in.
 
Scooter402 said:
You sure you didn't forget to carry the 2 or something? That sounds awful light... Post up some dimensions of the materials...I need something to do lol
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LOL LOL. yeah I just went and double checked..
add 92 lbs for rear bumper and materials in gas tank hold down area. so now we're at 384 lbs.
100lbs for winch..
door skins and random plates I have from doing leaf spring moutns figure another 25lbs..puts me at 509lbs...suppose that sounds more like it.

So is 500lbs a lot though? figure doors, windows, rear hatch, factory roof, windshield and back glass, pillars, carpet, dash, console, heater box, all the plastic pieces and headliner, speakers all had to weight what 200lbs?? so maybe gained 300 ish lbs in a cage when all said and done?
 
51.6 ft of 2.5x2.5 3/16 wall square
30 ft of 1.75" tubing .120 wall
43 ft of 2" tubing .120 wall
20 ft of 2" tubing .250 wall
10k winch
bumpers are 60" roughly of 2.25x2.25 .187 wall
that's the main stuff
 
Scooter402 said:
Assuming a linear spring rate - yes.

EDIT:

But, if those springs have been cut (I didn't study the pics), the spring rate is higher than 186 lb/in.
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so what you think of trying to use the 4" TJ rear springs then...even if it went up an inch, 4 1/4" lift wouldn't be that bad right? (can't cut the rear TJ springs since they are same small size on both ends and taper out way bigger)
 
Scooter402 said:
Yeah, 9" shocks definitely aren't enough for a suspension like that. I know you probably don't want to get shocks twice, but I found some el-cheapo's on eBay once upon a time that were long. IIRC they had something like 13-14" travel. Mind you, they were CHEAP...but they worked. Unless you want to save your nickels and dimes for some good ones, that'd probably be the better route.
Click to expand...
I have a set of 11.5 travel shocks I bought when I first built it ...they were like cheap cheap, older dodge rear shocks, good for travel but SUCK BAD for ride so I put on these 6.5" lift gas shocks that are really strong....for now
 
51.6 ft of 2.5 square .188 wall = 320 lbs
30 ft of 1.75 .120 wall = 65 lbs
43 ft of 2" .120 wall = 105 lbs
20 ft of 2" .250 wall = 90 lbs
60" of 2.25 square .188 wall = 25 lbs

Sounds to me like your total weight for the cage is ~580 lbs. Then 25 lbs each for the bumpers, add winch, etc. etc. I was just calculating total cubic inch of the steel, ballparking the density to be .283 lb/cu.in.
 
marty79 said:
so what you think of trying to use the 4" TJ rear springs then...even if it went up an inch, 4 1/4" lift wouldn't be that bad right? (can't cut the rear TJ springs since they are same small size on both ends and taper out way bigger)
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I don't know the differences in static spring heights, much less their rates. Those things can be sourced online. If I have a free moment tomorrow morning, I can look up some things to try to help. What springs do you have there now?
 
You should check the suspension movement with a driveshaft in it and see IF it'll even work. You may bind up a u joint in its yoke. That's definitely not something you want to find out the hard way.
 
Scooter402 said:
I don't know the differences in static spring heights, much less their rates. Those things can be sourced online. If I have a free moment tomorrow morning, I can look up some things to try to help. What springs do you have there now?
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currently the rear is stock XJ front springs
Croatan_Kid said:
You should check the suspension movement with a driveshaft in it and see IF it'll even work. You may bind up a u joint in its yoke. That's definitely not something you want to find out the hard way.
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wish I could but no yokes yet. the driveshaft will have plenty of travel in it. it's got plenty of pinion angle
 
a_kelley said:
F=½kx²

Where k is spring rate, x is compression from free length and F is force.

To calculate compression,
X=Sqrt(2*F/k)

Should be accurate for linear springs.
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mmm...I love it when you talk Physics to me. :D

But for springs, the spring equation is F=-kx. The equation you posted is work to compress/stretch a spring, or energy stored in the spring once it's moved. So that would be W=1/2kx^2.
 
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