Engine/Transmission (1994 - 1998) 4link coil conversion opinions wanted

[Mhannink]

well like the title states im looking for opinions on how to do a 4 link for my truck. the ideas i have in mind are one regular non triangulated 4 link w/ panhard bar like the front. second idea is triangulate the front and leave the bottom ''normal''. with this though im not sure whether or not i need the panhard bar. the third one is to triangulate the top and bottom inverse of each other. this would eliminate the need for the panhard bar. the first one if the one ive been thinking about doing most since its like the front and the front flexes pretty well. this would also elminate the axel wrap that i have in the rear which is the biggest reason for doing this. i am looking for opinions on the rest though too so i can decide which one is best. it is the 95 in the sig and it does a fare amount of off roading. not just mud either to a more hardcore off road suspesnion is something i would consider as long as it can handle weight keep axel wrap in check and obviously flex a good bit. this truck will eventually pull and so that is also something that needs to be keept in mind. well thanks in advanced for the help now lets hear what all have to say

 

[MMcCallie]

All you need to cure axle wrap in the rear is stiffer suspension. That or traction bars. If you triangulate both the uppers and lowers opposite each other for your front 4 link you are right, i don't think you'll need a Panhard Rod/Track Bar. Probably so with only one set triangulated as well.



I don't like Panhard rods because you have to get the angles perfectly aligned with the angle of the tie rod between the Pitman arm and steering knuckle or you get bump steer. They must be parallel. I think they should both ideally be parallel to the ground as well, assuming suspension droop and up travel are about equal.



If you're going to rock crawl, you might want to make your upper links longer than your lower links for ground clearance. Ability to do so will largely depend on how much lift your giving your rig, and how much fabricating you can manage. If you use a sway bar that will help locate your axle as well.

 

[Mhannink]

mmccallie i know that a stiffer suspension or trac bars would help axel wrap but im trying to also improve my suspension and ultimetly just build things. i am a fabricator by trade or will be anyways (goign to school and doing really well also is the biggest reason for doing this) so desiging, enginering, and building it is not hard for me to do. the 4 link i want to build is for the rear i am only going to beef the front up since it does fine. the panhard bar therefor is not as big a deal as it is in the front. if i where building the front then i would have to worry about that. however in the rear i do not think this is a great concern. as for the lift right now im doing it to stock hight putting coils in where the leafs should be and the 4 link to hold it all there. later i plan on doing a 4'' lift w/ 35/12. 5/17 toyo open countries mts. anyways ive been thinking a paralell 4 link w/ the panhard bar because it is easier to set up and i know will transfer weight like i want it to as far what would be axel wrap into down force which will allow me to drag and pull better(both i intend to do a little bit) and give me more flex then leaf springs to four wheel with. as for off roading i dont quiet rock crawl but the flex that this suspesnsion offers would definatly help me out. for those looking to put their opinions up im basically looking for a nice suspension that can do all the listed above rather well maybe not the best for each field but will still be improvement over the leafs. any other suspensions that will do this besides some type of 4 link will be appreciated. though i must admit im rather stuck on the 4 link just not sure how best to set it up whether its paralell, upper triangulated, or double triangulated. again all thoughts and opinions are appreciated and wanted so please give thanks again matt

 

[wildmanben]

check out Scotts BigBadDodge. He has a setup that he built

 

[CSchafer]

I have done quite a bit of reasearch on the topic because it was my plan to 4 link my first gen. The best set up would be a triangulated 4 link as you mentioned. The problem is that the fuel tank and other stuff seams to be in the way or at least make it a pain. a paralell link setup would be much easier and a panhard bar may have it's disadvantages but bottom line is it's a strong link doing nothing but keeping the axle under the truck and that is a good thing to have. Another problem with the triangulated setup is the fact that your dealing with fairly long links and such a heavy truck. I learned the hard way how much steel it takes to keep a diesel pickup from wondering around.



A couple other ideas would be too use a ladder ber design. With the rear end you don't have to worry about caster angle so there is really no point to have a 4 link. They are much easier to design and build and offer traction,strength and articulation. A panhard bar would have to be used agian but agian I like them. The only draw back is the coolness factor but I think they still look cool. The other idea and maybe the best idea would be a 3 link wishbone type. The botom links would be the same as a parallel 4 but the top link is a triangle with one conection in the center of the truck and two connections at the axle. This setup would do away with the need for a panhard bar, provide much more strength and be easier to build. Check out fabtechs jeep TJ system for some pictures.



No matter what you decide I would strongly recomend the use of rubber joints or a full ball and socket style joint (johny joint) not hiems as they wear pretty fast. Rubber joints flex alot more that most people think(or hope )



Sorry for the long post, I love suspension design

Make sure to take pictures and tell us about how you do it.

Cade

 

[Mhannink]

cschafer thanks for the input those are the ideas and reasonings im looking for. one thing id like to mention is that i did think about doing ladder bars but to me it doesnt seem much easier(could be wrong) and 2 you dont have the adjust ability that you do w/ the 4 link. also w/ the ladder bars. as i see it when the axel flexes your wheel base changes which may or may not be good. again i could be wrong but since the ladder bars only connect in one spot on the frame the tend to move in an arc and there for moving your axel forwards as it flexes up or down. i dont like the idea of that since it would pull on your drive line and stress that out which could get you into all kinds of other problems. thats whats attracted me to the 4 link when it flexes it holds the axel in the same spot only letting it move veritical up and down and not moving fowards or back. again i could be wrong about that and if so please correct me.



so far i am still leaning to the paralell 4 link w/ a panhard bar though im not conviced and still want to hear all ideas and concepts. maybe someone will have something better. so keep the ideas coming. also im would be willing to possibly be a guinea pig if someone has an idea they have been working on and has a way of sending me the plans/idea for me to work on. i too love the challenge of desgining suspension.

 

[JPittinger]

cschafer thanks for the input those are the ideas and reasonings im looking for. one thing id like to mention is that i did think about doing ladder bars but to me it doesnt seem much easier(could be wrong) and 2 you dont have the adjust ability that you do w/ the 4 link. also w/ the ladder bars. as i see it when the axel flexes your wheel base changes which may or may not be good. again i could be wrong but since the ladder bars only connect in one spot on the frame the tend to move in an arc and there for moving your axel forwards as it flexes up or down. i dont like the idea of that since it would pull on your drive line and stress that out which could get you into all kinds of other problems. thats whats attracted me to the 4 link when it flexes it holds the axel in the same spot only letting it move veritical up and down and not moving fowards or back. again i could be wrong about that and if so please correct me.



so far i am still leaning to the paralell 4 link w/ a panhard bar though im not conviced and still want to hear all ideas and concepts. maybe someone will have something better. so keep the ideas coming. also im would be willing to possibly be a guinea pig if someone has an idea they have been working on and has a way of sending me the plans/idea for me to work on. i too love the challenge of desgining suspension.

A 4 link still moves in an arc similar to ladder bars. The slip on your driveshaft allows "the wheelbase to change" like you said. Draw it out on a piece of paper with a compass to prove it to yourself.

 

[MMcCallie]

The more suspension travel you have, the more your Panhard rod will push your axle to either side. This will affect traction during extreme articulation. Yes, it can be easily adjusted and helpful to center your axle at normal ride height, but i'd try to steer away from it if possible.

 

[CSchafer]

correct on the four link still moving in an arch. The key to that is long bars to make it a bigger arch. Check out the wishbone I think it's best of all worlds.

 

[Mhannink]

well after i made the post i was thinking on what i had said and realized my error on the 4 link and ladder bars but thank you anyways for pointin out that error. a wise man learns from his mistakes. anyways mmccallie yes i know the panhard bar will move the axel side to side in extreme articulation however since the front has one from the factory i think ill be fine with one in the rear since there is really no point to have more articulation in the back if the fronts cant get over it to let you flex the rear. however i do see your point and do agree if you have a good reason though why more flex in the rear could be benifical ill definatly not ignore you.



cschafer tell me more about this wishbone suspension setup advantages/disadvangatges the whole 9.

 

[MMcCallie]

Make sure both front and rear are angled in the same direction or you'll get sidetracked. Meaning, if the front mounts on the driver's side to the frame and the passenger's side to the axle, the rear will need to do the same. Otherwise, your truck will feel like it is travelling sideways under articulation.

This way, when your suspension droops, front and rear tires will swing out toward the driver's side. However, when you encounter bumps at speed, the truck will also seem to rock to the side.

 

[CSchafer]

Crude drawing of the three link wishbone suspension. It provides great flex and strength while doing away with the need for a panhard bar and also will change you pinion angle with suspension movement, for the better if done correctly. Fabtech builds one for the jeep tj and it is big in the mini truckin world. In fact get a copy of mini truckin magizine and it will have all kinds of linked suspensions for you to look at.



I can change the color of the links to match your truck if you want. :-laf

 

[Mhannink]

Crude drawing of the three link wishbone suspension. It provides great flex and strength while doing away with the need for a panhard bar and also will change you pinion angle with suspension movement, for the better if done correctly. Fabtech builds one for the jeep tj and it is big in the mini truckin world. In fact get a copy of mini truckin magizine and it will have all kinds of linked suspensions for you to look at.



I can change the color of the links to match your truck if you want. :-laf

lol yeah truck is red and black. ok that looks good to me now whats the trick to get the pinion angle to change in a good way

 

[JoshPeters]

Great stuff guys! I've had a mental picture in my head of a 4 link with air bags for my truck. This is just the type of discussion I was looking for!



JP

 

[CSchafer]

As said before a piece of paper and a compass will tell you what radious the axle will follow for the given length of links. By drawing out the senirios you can see what the axle will do at sag and compressed with differnt length bars. It all depends on what angle your bars and pinion will be at set at ride height. But since this is not a race car and it is just the rearend I would make the links as level as possible, as close to the same length as possible and make them as long as possible. I have a video of a 4 linked, air baged,twin turbo cummins powered suburben on 44's. It's links were six feet long. It was SWEEEET.

 

[Mhannink]

cschafer ive got a ? for you w/ the 3 link would it be possible to reverse it. put the 1 connection point on the axel. would it still locate it. reason i ask is i think it would provide a little more flex expecilly w/ some johnny joints in there and hiems or equivelent on the chassis. what do you think?



joshpeters its funny you mention bags. my intention after doing all of this is to add air bags on down the road. my plan is to lighten the spring rate so that they are softer then adjust the ride w/ the air bags. am also planning to put rancho shocks i think they are the 9000 series w/ the in cab controler to adjust them. i figure it would ride like a cadilac, pull like a freight train, and off road w/ the best of them.

 

[JoshPeters]

Untill this thread came along I was basically planning on doing what Scott has/had done with BBD. I was also going to take some pictures of Semi Trucks suspension and see what they do. Problem with that is... . I think they just use one really big arm to the bottom of the axle and a Track Bar.



I do like the idea of the V shaped deal to the top of the differential as well. Mine won't see off road, so I don't know if that is nessissary.



JP

 

[CSchafer]

shouldt matter on witch way the wishbone gets put in. My 90 is set up with leaf springs that are too soft and It actually rides on the air bags. The springs do most of the work so I don't have to run so much pressure in the bags. Works pretty good and rides alot better than it did.

 

[Mhannink]

josh semis use leaf springs w/ the air bag connected where there normaly would be a shakel. as for what we are cooking up here they offer more options and adjustability. plus they are going to ride a lot nicer then the ones the semis use. as for bbd's setup i havent seen it so i wouldnt know. the wish bone/3 link that we are talking about will probably be best all around since it will negate the need for a track bar which moves the axel side to side as it flexs. not a big deal for you if your not offroading but still works good. basically anyone of these would help you out. giving you the options to mount air bags or what not to make the ride real nice. cshcafer im thinking i might use your suspension idea the 3 link sounds like the best of all worlds. im still deciding though so who knows. look for pics to come sometime in january.

 

[JPittinger]

... and off road w/ the best of them.

Unfortunately, Rancho shocks and airbags WON'T let you offroad with the best of them. The Rancho's will overheat and self destruct on the first sustained high speed blast and the shafts are too skinny to take a hit. King or Fox is a great way to go.



The airbags won't give enough articulation for a rock crawler unless you mount them forward of the axle, which will put extreme strain on your tubing based 4 link.