watts link

[CamaroAJ]

where is a good sorce for a watts link set up? i was able to find this one http://www.suicidedoors.com/4-link-kits/thorbecke-brothers/watts-link-universal-kit but i know there has to be others out there. is there a better one than the one i posted or are they all about the same?

[jknight16]

Fays2 builds a very nice Watt's link setup. I just completed the install on my car and am in the tuning and minor refinement phase. It's a really nicely built setup with quality hardware and components. Mark at SC&C can set you up with a kit.

If you're a good fabricator and understand suspension engineering, the kit in the link you posted might be pretty good. For me, the added cost of the Fays2 kit is more than worth it for the time and potential mistakes it saves me.

[CamaroAJ]

link to it?

[jknight16]

http://www.scandc.com/wattslink.htm

http://www.fays2.net/

[CamaroAJ]

cool, thanks.

[ZZ427]

Let me know how this goes , I am also
contemplating on this set - up .

[The WidowMaker]

stick to a chassis mounted watts like the fays. the first link appears to be a diff mounted watts, and not only do they add unsprung weight, but you cant alter the RRCH.

i got all my parts from fays. great guy to work with. or just call mark and get the whole kit.

[JRouche]

For a ready made watts link I like the Fays. And Jim is a great guy to talk with. Give him a call and he may be able to answer some questions.

I kinda built up my own using his center pivot. His center pivot is a really nice piece so I imaging the complete system is well made. JR

Here is mine, the build. https://www.pro-touring.com/forum/showthread.php?t=55420

https://static1.pt-content.com/images/pt/2009/05/c-3.jpg

https://static1.pt-content.com/images/pt/2009/05/d-3.jpg

https://static1.pt-content.com/images/pt/2009/05/e-3.jpg

[CamaroAJ]

i planed on building my own but was unsure about the pivot link. i wanted something that didn't look cheep or flex on me too much. i'm glad you can buy it without the kit, this saves me alot of money having the local machine shop mill me out what i wanted from aluminum.

[Twentyover]

stick to a chassis mounted watts like the fays. the first link appears to be a diff mounted watts, and not only do they add unsprung weight, but you cant alter the RRCH.



I think there's more to it than that. A chassis mounted watts maintains the same relationship between roll center and CG as the suspension articulates.

If the watts is axle mouted, it seems that the change in relationship betwen cg and RCH would kind of cause the rear to 'wag' around a bit , as the roll angle is a function of distance between the two points.

Am I all wet here?

[CamaroAJ]

it would also be sprung weight so that is a plus.

[wendell]

stick to a chassis mounted watts like the fays. the first link appears to be a diff mounted watts, and not only do they add unsprung weight, but you cant alter the RRCH.

i got all my parts from fays. great guy to work with. or just call mark and get the whole kit.
The RRC can be altered in the same maner as a chassis mounted pivot. I would make the range from axel center line to 3" bellow. Also, when executed correctly, the undsprung weight of a diff mounted pivot islighter than the diff brackets needed for a chassis mounted pivot.

Considering the tom foolery going on with most of the rear suspensions being marketed to the "pro-tourers" I wouldn't worry about the roll center migration. If you want a cool watts link, let packaging primarily dictate your design.

[CamaroAJ]

i would like something that works rather than something that looks good. i think i am going to base my design off the LD 3 link.

[wendell]

i would like something that works rather than something that looks good. i think i am going to base my design off the LD 3 link.
What rear suspension are you pairing this with?

[CamaroAJ]

3-link

[The WidowMaker]

I think there's more to it than that. A chassis mounted watts maintains the same relationship between roll center and CG as the suspension articulates.

you are correct, theres a lot more to it than that. its where i would normally enter my "call mark when you have an hour available" plug, but i missed it.


The RRC can be altered in the same maner as a chassis mounted pivot.

on most of the diff mounted i have seen you are correct, but i was referring to the one in the pic above. it appears to have a solid mount.


Also, when executed correctly, the undsprung weight of a diff mounted pivot islighter than the diff brackets needed for a chassis mounted pivot.

im not sure how i see that as being possible. if youre using a 9" and solid mounting the pivot then maybe. but by the time you add the adjustment plate, reinforcement and the bell crank, it would out weigh my 1.5" dom tubing used for my axle mounts. if youre running a 12 bolt, there really is no way since you have to build a cradle that ties in both sides.

[Twentyover]

on most of the diff mounted i have seen you are correct, but i was referring to the one in the pic above. it appears to have a solid mount.




If you're refering to the pictures in post 8, there is adjustment of the propeller elevation (see 1st and 2nd image) It also appears to be a chassis mounted watts

[The WidowMaker]

no, post 1. jrouche (post 8) used the same parts i did, and we both fabbed up a chassis mounted watts.

this is the one i was referring to

https://static1.pt-content.com/images/noimg.gif

[JRouche]

Considering the tom foolery going on with most of the rear suspensions being marketed to the "pro-tourers" I wouldn't worry about the roll center migration. If you want a cool watts link, let packaging primarily dictate your design.

Hey, My name isnt Tom, its John LOL No yer right. There are so many companies out there shoving too many products in our faces that its difficult for the average Joe, (or John) to decide what he needs.

I put in the watts link for the sole purpose of packaging. My car is pretty tight for space at the rear due to the fuel cell that a watts link was the only option for me. I really wanted to keep it simple and use a pan hard bar. But the space was not there.

And as far as a diff or frame mounted pivot point is concerned. Well, I cant say which is better. Because packaging again comes into play. And every car has its own packaging issues.

And for performance. Well, the changing RRC height with suspension travel is something to consider with a rear end mounted pivot. But to be honest, for a street car it may not cause much of an issue.

There are many guys that dont even have to consider that issue. I for one dont. Im not at that level of tuning. But it is a consideration. I think many guys have other areas of the suspension that could use some help with the basics so changing RRC heights are overshadowed. Not to say whittling down on all the details of the suspension is a worthless endeavor. Whittle a lil here and there and before you know it you have cured some issues a lil at a time.

And the unsprung weight issue. Again it may not matter. But if it does the axle clamps I used are prolly lighter than some of the cages I have seen that are used to make a stout axle housing connection point. But to be honest. Some other areas of unsprung weight like heavy brakes, heavy wheels, heavy tires and a heavy axle housing will accumulate to more unsprung weight than an axle mounted watts pivot point will. But for a guy that is looking at ALL the unsprung weight then that might be something to look at. But for the most part I dont think it matters much for the watts link brackets. Compared to all the other heavy items on the axle housing.

IMO the center pivot mounting needs to be so strong that you wont worry if a tow truck hooks up to it and pulls your car sideways. It needs to be that stout. And to make an axle housing mount that stout for many rear ends the cage is gonna be as heavy, more than likely heavier than the axle clamps I used. Oh, and yes, I wouldnt hesitate letting a tow truck hook up to my center pivot and drag the car sideways. Its that strong.

And as far as looks or whatever. CamaroAJ (Umm, the original poster) talked about that. I agree. It should perform first. The looks dont matter IMO. What matters is the job the part is supposed to do. Yer right on there AJ. The function comes WAY before the form. I think the form (the looks) are the last on the books. Function is all that matters for cars that are meant to be driven. Im with you on that one...... JR

[ITLBTU]

Here's a thought... Will an aluminum cover with an adjustable bracket welded on it be strong enough to support the center pivot? That would definately have a lighter unprung weight. The con to doing that is then you would need more weight in bracing two outside brackets that would be adjustable. On a full tube frame race car that's not a problem, but on a street car it may be a different story...

[ITLBTU]

Hey, My name isnt Tom, its John LOL .... JR

John, I like the looks of your watts link, as I am a low buck make it myself type of person... I am curious how your 4-link handles in the curves though. Isn't that more of a drag race set-up?

[JRouche]

John, I like the looks of your watts link, as I am a low buck make it myself type of person... I am curious how your 4-link handles in the curves though. Isn't that more of a drag race set-up?

Hi, thanks. Well, Ill let you know when I drive it LOL YUP.. After 15 years Im still making the car and not driving it. Life got in the way for about ten years. Marriage, new house, kids and job. Now that the job is outta the way I am ramping up the work on the car. Oh, the wife, house and kids are still here :)

Ok, back to the car. You are correct, the 4-link I bought from art morrison was designed for a 1/4 mile track. Or at the time a pro street car. This was back in 95 when I bought it. They still sell the exact same package. Its pretty solid. You can stuff a 1500hp mill in front of it and carry yer butt down the track without worrying about the rear end coming apart.

But that was back then and this is now. I never planned on using the car on the strip. I just needed the endless adjustability of the 4-link while I was building my car. In 95 there was no such thing as an aftermarket rear suspension for a 62 nova. So it was either build my own and that was outta the question, I dont have the skills, or purchase what was available. Art Morrison was there. They asked for all my needed numbers. Like ride height, tire and wheel size, and basically just what car it was going under. It fit like a glove. They had their numbers correct. And remember, its not just a bolt in 4-link. Its a full rear framework that was welded into the sheetmetal of the car.

Ok, I did drive the car, not much, just around my neighborhood. And just those small tours showed me the car wasnt gonna be good for me. Mainly, the super short pan hard bar. It allowed the rear axle housing to wander too much. Kinda scary actually. It felt like the entire rear end was coming out and off the body. Thats just how it felt, it prolly wasnt moving as much as I thought it was. But that was enough. So I looked long and hard to fit a longer pan hard bar under the car. The one I had was only 24" long. Way to short for street driving. Well, after a long look a proper 45" or longer bar wasnt gonna fit. So I decided on a watts link.

One other part of the problem was the location of the "coilovers". They were also set way inside, 24" apart and vertical. The reason? Because with the frame AM supplied I could use as wide of a tire that was made. The coilovers were placed in tight, close together. It was designed to use some very wide tires for the track or pro street. But now Im looking into pro touring. I needed some different performance from the suspension and not as much pro street but more pro touring, I wanted to turn corners.

So I ditched the coilovers and mounted some air springs. Mounted them so they would have more control over the end of the axle housing.

Then there was one more part of the original suspension. Prolly more of what you are asking about. The articulation of the arms within the mounts. The original suspension came with some very stout stainless steel poly rod ends. Problem? They didnt allow enough rotation of the axle housing. The ends were captured tightly within the frame tabs. And the poly would allow for about 3* of axle rotation. But would bind up after that. And so what I saw was the jamb nuts working their way free to allow for the needed rotation. No matter how tight the jamb nuts were. They would break loose and then I had a free control arm. NOT good. The rod ends would be free to rotate on their threads. No good.

So I replaced all the rod ends for spherical ends. Some nice QA1 rod ends with seals-it end caps.

I have a completely fluid rear end now. It will travel through over 6* of rear end rotation with no binding.

And back to your question. Is it suited for the street or turns on the track. YES.. The 4-link I have has very long arms compared to some of the bolt in systems you will see. Specially the upper arms. The spread (vertical distance) from the uppers to the lowers is huge, a plus. My rear seat is gone :( It was not needed anyway. So there isnt any twitchy-ness with a short arm 4-link (short upper arms). And because its a TRUE 4-link it has an endless amount of adjustments for the arms. Talk about too much adjustability to get you into trouble. A proper 4-link will do just that.. Whole nuther discussion....

Ok, here is an example.. A longish lower bar 4-link will have some decent qualities. But the upper bars are usually short (unless its a full four link). So from ride height, in a left hand turn the upper bars start pulling the axle housing dramatically. The shorter the upper bars the worse it is. So it pulls (outside tire) the tire in while the axle housing is going through its travel. You dont want the tire to be pulled forward or pushed back. You want it to stay constant within the vertical plane. But suspensions are on pivot points and they will rotate on those points. But the longer the arm is the less the opposite end of the link will rotate on that pivot. Larger circle (long arms) smaller fore and aft motion of the rear end.

Same thing with the front end. You want as long of a suspension arm as possible to reduce the amount of travel (in and out) that the other end of the arm will travel.

On a rear end its pretty easy to package a long lower arm. Torque arm or Truck arm suspension is a great reference.

But for packaging the upper arms usually fall short. Thats where a three link kinda shines. For packaging its easier to place one long bar in some cars then to place two long bars.

Oh, back to why short uppers have alot of influence. A short upper bar will pull the rear wheel and tire in, more dramatically than a long bar will. So say you are taking a tight left turn. The outside (right tire) will have more influence. In a strong left hand turn the short upper arm will pull the tire in to the front of the car faster and more of a distance than the same car and suspension with a long upper arm. As the rear compresses (right side) on a left hand turn the upper arm will pull the wheel and tire forward. That will cause understeer. Do I have it right? As the rear compresses on a left turn , the top of the outside arm on the right side rotates up and pulls the housing forward. Twisting the rear end counter clockwise as looked from above causing understeer in the left hand turn? Its late and my visual functions have left the house.


I think I have it correct. Its common for cars. Understeer. Short upper trailing arms cause alot of understeer.

Solly.. You asked about my suspension. If it will handle the curves. I think so. Ill let you know if I ever get to drive her ... Errrr. I am close. JR