2000 3 link build

[AzRat]

So I was tired of bending leaf springs, and I had some time, so I started my three link swap. Basics of the truck:
3.4L S/C URD, HP60 FF14, Marlin 4.7, PSC assist. Lowers links are 2.5/.375 DOM with 3" Ballistic joints. Upper is 1.5/.250 DOM with 2.5" Ballistic joints. Hiems all the way around, double shear on on steering arms and pitman arm. Links and tierod are 3/4" hardware. Steering and panhard all 1.5"/.250 DOM. This has been a huge learning experience so far and plan on hearing more here, both good and bad.
Some pics
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Currently adjusting the seperation at the frame for the upper link. It is at 2" and needs to go to 4.5" since the axle sep is 9". The axle was rolling forward too much and the tierod got into the pitman arm. You can kind of see it in the pics. Started the CO mounts this weekend. Should be able to get some pics up soon.

[tnxjjeeper]

That is looking good, pretty similar to mine. What size coilovers?

[Booger Weldz]

nice! tight fit in there!

[AzRat]

Originally Posted by tnxjjeeper

That is looking good, pretty similar to mine. What size coilovers?

16" SAW's. I think I may have choosen the wrong spring rate. I went with 250 over 300 and it may be too soft. Should have it on its own weight by the end of the weekend...fingers crossed!

[AzRat]

Originally Posted by Booger Weldz

nice! tight fit in there!

That has been the biggeet challenge. Although it is nice with links in that things travel on a single path, or radius if you will, no moving around like with leafs having a few minor interference issue, but should be able to resolve fairly quickly.

[alienjeep]

too soft on the springs? mine was too stiff with 300 and 275 (2.7L motor), i'm trying a different route that a guy here in pirate told me so i'm giving a shoot to a 14" 90lb spring over a 18" 300lb with a helper spring, we'll see how she handles.
trucks looks really good man, congrats!!!

[ErikB]

Wow, that's some major beef!

Originally Posted by AzRat

16" SAW's. I think I may have choosen the wrong spring rate. I went with 250 over 300 and it may be too soft. Should have it on its own weight by the end of the weekend...fingers crossed!

Originally Posted by alienjeep

too soft on the springs? mine was too stiff with 300 and 275 (2.7L motor), i'm trying a different route that a guy here in pirate told me so i'm giving a shoot to a 14" 90lb spring over a 18" 300lb with a helper spring, we'll see how she handles.
trucks looks really good man, congrats!!!

Don't know if you guys have played with Billavista's coilover bible and his excel spreadsheet in there, but it can definitely help playing with spring rate numbers.
You are basically shooting for a ratio of rig weight (sprung weight) to spring rate, which is the "Fn" (natural frequency).
You can get a very good idea of your sprung weight by setting your rig on its coils and measuring how much they compress, then multiplying the spring rate times the inches compressed.

If you like high speeds and/or drive it on the street, you'll want to go towards the higher Fn numbers like 1.4. If its slow rock trails only, then you can you can get away with lower numbers, but lower numbers also mean it will lean more and you may need sway bars, etc.

I started off on my 4runner with 275/200 (116 combined), which was way low. It leaned badly on the street, and the chassis torqued a lot under power (no sway bars), and was generally fairly mushy feeling. I've got a sprung weight of about 800lbs/corner up front, so that gave me an Fn of about 1.19. Swapping to 350/275 (154) puts me up about 1.37, and it feels a lot better so far . I know 350/250 (146) is a fairly common rate on swapped Taco/4runners and is pretty close too. (I'm also running sway bars now too, and it handles GREAT on the street while still doing well offroad)

300/250 > 136
300/90 > 69 way low for a heavy rig!
If your front corners are 700(?? then that would give you an Fn of about .98, which is way down in the rock buggy only range. I guess that could be ok if that's what you're after. It will probably suck for most anything but crawling.

I've got helper springs on there too. All they do is help hold everything together at full droop. They don't factor into spring rates or handling, etc. They can affect what spring lengths you can fit though if you are running out of room.

One thing you can do to help handling/body roll too is to set your dual rate slider stop ring so that the higher rate kicks in fairly early, like after only 1" or so of compression travel. You might have to play with different spring lengths to be able to get the stop ring to hit where you want it to though.

[whiteDI]

What are the lengths of the lowers and upper?

[AzRat]

Thanks for the explaination ErikB. I played with the calculator and knew I would be wrong. My sprung weight per front corner is around 1200lbs. I do drive it on the street and do like a little high speed stuff as I used to race in the California Rally Series.

WhiteDI, the lowers are 43" eye to eye, and the upper is 37".

[alienjeep]

Originally Posted by ErikB

Wow, that's some major beef!





Don't know if you guys have played with Billavista's coilover bible and his excel spreadsheet in there, but it can definitely help playing with spring rate numbers.
You are basically shooting for a ratio of rig weight (sprung weight) to spring rate, which is the "Fn" (natural frequency).
You can get a very good idea of your sprung weight by setting your rig on its coils and measuring how much they compress, then multiplying the spring rate times the inches compressed.

If you like high speeds and/or drive it on the street, you'll want to go towards the higher Fn numbers like 1.4. If its slow rock trails only, then you can you can get away with lower numbers, but lower numbers also mean it will lean more and you may need sway bars, etc.

I started off on my 4runner with 275/200 (116 combined), which was way low. It leaned badly on the street, and the chassis torqued a lot under power (no sway bars), and was generally fairly mushy feeling. I've got a sprung weight of about 800lbs/corner up front, so that gave me an Fn of about 1.19. Swapping to 350/275 (154) puts me up about 1.37, and it feels a lot better so far . I know 350/250 (146) is a fairly common rate on swapped Taco/4runners and is pretty close too. (I'm also running sway bars now too, and it handles GREAT on the street while still doing well offroad)

300/250 > 136
300/90 > 69 way low for a heavy rig!
If your front corners are 700(?? then that would give you an Fn of about .98, which is way down in the rock buggy only range. I guess that could be ok if that's what you're after. It will probably suck for most anything but crawling.

I've got helper springs on there too. All they do is help hold everything together at full droop. They don't factor into spring rates or handling, etc. They can affect what spring lengths you can fit though if you are running out of room.

One thing you can do to help handling/body roll too is to set your dual rate slider stop ring so that the higher rate kicks in fairly early, like after only 1" or so of compression travel. You might have to play with different spring lengths to be able to get the stop ring to hit where you want it to though.

with my 90lb and 300lb springs im sitting right where i want to be, i know the 3rd spring only holds everything in place under full drop, i know is gonna be a little too soft, BUT you can always play with your valving which you didn't mentione. mine is not street driven at all so it don't matter, the way i have it set up its for multipurpose, i have 6" uptravel, i don't do much fast stuff maybe a jump here and there but not much. like i said, i haven't try it yet will see how she handles once i take it out.
and yes i read billavista bible, some of that stuff is just way over my head

[AzRat]

"Wow, that's some major beef!"

Yeah, I come by the nickname "Overkill" honestly. However, the Az rocks have a way of making even the badest rigs groan.

[AzRat]

Took some ideas on previous designs and came up with this CO mount. I was cringing about the fact that I had 2 11" pieces of 2.5/.375 DOM from my lowers and put them to use. I sleeved it about 4" down with a scrap piece of 1.5/.250. Gussetted it and even with tacks it won't deflect pushing as hard as I can from the side. Anyway, to the other side...
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[Booger Weldz]

beefaroni!!

[AzRat]

[alienjeep]

really nice man! keep it coming!!

[ErikB]

I was wondering how your rig could be 1200lbs/corner up front sprung weight (~50% heavier than my 4runner ) but seeing how you build stuff, maybe that's not so far off after all!

That 2.5x.375 tube is nearly 9lbs per foot all by itself!

[AzRat]

Yep, the trails out here have a way of eating even the best built rigs. I am 5400 lbs total, 3250 front, 2150 rear. Figure wheels and tires weigh 300lbs for the front two, and another 750 lbs for the front axle with all the steering stuff. That leaves about 2200lbs of sprung weight, or about 1100lbs per corner, +/-. All that weight helps keep the COG low though

[AzRat]

Some updates
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The last picture shows one of the clearance issues I am having. Uner full stuff, the top/side of the high steer arm hits the coil. Also, on the driver side the coil hits the frame side panhard mount. I really dont want to shorten the panhard but might have to move it about 3/4". For the top plate on the steering arm I am thinking about chamfering the edge with the grinder. I only need about 1/2" to clear the coil seat. Thoughts??

[Bigger Valves]

Originally Posted by alienjeep

..... i know is gonna be a little too soft, BUT you can always play with your valving which you didn't mentione.

But do you want your shocks to be fighting your springs and making up for the work they should be doing or do you want them to work together? Think about it. It's a lot more fun to "play with valving" when your springs are performing their intended function properly. I'm not saying 69 lb/in won't work, just saying keep this in mind. Out of curiosity what makes you say 300/275 was too stiff?

Originally Posted by alienjeep

and yes i read billavista bible, some of that stuff is just way over my head

Sorry!

[AzRat]

Got it down on all fours today!
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[Booger Weldz]

holy fawkin sweet!!!!

[AzRat]

So, knowing very little about coilovers.....question. I did not preload the CO's before I dropped the truck on it weight. The adjusting collar is all the way to the top and the truck is sitting at the intended ride height. Is it normal to not have to put any preload on the coils? I could not lower it unless I mover the upper mount. Right now I am at about 4.5" of uptravel.

[Bigger Valves]

Originally Posted by AzRat

Is it normal to not have to put any preload on the coils?

Yes. This is the reason helper coils are so popular.

There is another way to lower it and keep the same suspension frequency (if you wanted to) along with moving the upper mount and that is to use shorter free length spring/s. Sounds like your setup needs helpers anyways.

[AzRat]

I see. I will look into that some more. I have a lot to learn about spring rates, valving, and such. I know lots about leaf springs though

[ErikB]

If/when you add helpers, it will take up space in the coil stack and lift you further (~3/4"), so you might want to install some shorter springs at the same time. If you've got two 16's, then switch a 16 and a 14, and move the adjuster down 2" (or 1-1/4" with the helpers) and you will be the same height if you use the same spring rates. You'll probably want the top spring to be the shorter one.

I'm running a 14 and a 12 on my 14's, with helpers.


It looks like your drag link/pitman are over your TR, limiting up-travel quite a bit?