Watts link for first gen camaros

[LV42DAY]

so i recently bought a four bar/link kit for my 68 camaro convertible. the kit came with a panhard bar, which a lot of people swear by but i have been doing a lot of research on the watts link and am now dead set on getting one.

there is not a lot of aftermarket support for the watts link as far as i can tell so despite searching for the last few weeks, when time aloud me, i did not find too much for the first gen camaro. they seem to be big in the mini truck industry primarily due to the insane amount of suspension travel those guys use on their trucks.

the only direct bolt on kit that found is the fays2 kit for $650+shipping, found here: http://fays2.net/fays2_watts_link_15_.html

it does look like a solid kit and resembles the older lateral dynamics three link watts link that are found on some of the other high end PT camaros on this site. unfortunately, this is the only one i could find that is specifically for a first gen camaro.

other kits that could easily be modified to work:

KP Components:
Rear gear cover mounted $369:
http://www.kplinks.com/product.php?productid=306&cat=79&page=1

Dallas hotrods has three different style:
rear gear cover mounted $250:
http://dallashotrodparts.com/wattsrearcovermount.html
axle mounted $229 (thinking about getting this one):
http://dallashotrodparts.com/wattsminitruckhdheim.html
chassis mounted $299:
http://dallashotrodparts.com/chassiswattsrg.html


now i've done a lot of reading regarding the watts link location. i've seen some people say that the axle mount is the way to go due to better articulation of the rear end in comparison to the chassis mount and vise versa.

anyone want to chime in and potentially clear up what really works and what works best.

please keep this thread factual.

here is a good thread with good information despite the cat fighting that was going on during the debate:
http://www.thirdgen.org/techboard/suspension-chassis/484938-anyone-see-new-watts.html

site showing how the watts link works for anyone who might not know or wants to learn more:
http://en.wikipedia.org/wiki/Watt%27s_linkage

[CamaroAJ]

i have an early LD 3 link and it uses a fays2 bell crank. i think there is a reason that LD and fays2 doesn't axle mount the bell crank.

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

[Vicinity]

Gonna tag this, I'm interested. I've been looking at the Fays2 link, don't really understand it, does it utilize the leafs?

[Gitter Dun]

Yes you can use them with leafs.

I have a Fays2/leafs in my car but haven't had a chance to put it to the test yet. Completed install about 2 weeks ago. I have been making suspension changes to my car and documenting results after each change by comparing lap times. I've been told that you can get into the throttle sooner coming out of a corner but we will see.

[Vicinity]

Yes you can use them with leafs.

I have a Fays2/leafs in my car but haven't had a chance to put it to the test yet. Completed install about 2 weeks ago. I have been making suspension changes to my car and documenting results after each change by comparing lap times. I've been told that you can get into the throttle sooner coming out of a corner but we will see.

So it does nothing to affect ride quality, just allows better traction in curves? I'm wondering how different it and a 3 link (like the LD posted above) would really be.

[zamora7]

So it does nothing to affect ride quality, just allows better traction in curves? I'm wondering how different it and a 3 link (like the LD posted above) would really be.

The watts link and a panhard bar is used to keep your rear end center with the car. The watts is actually better since the rear end stays centered at all times compared to a panhard bar which in hard cornering can still shift the rear end/car to one side. In other words, if your tires are sticky enough the rear end will stay put and the body shifts towards outside of the turn and your tires will rub, like my 4th gen T/A:crying:. Also, if you lower a car with a panhard, you'll need an adjustable one to re-center the rear end or you will need tires real quick.

[Gitter Dun]

So it does nothing to affect ride quality, just allows better traction in curves? I'm wondering how different it and a 3 link (like the LD posted above) would really be.

I haven't noticed any difference in ride quality. The main reason for the watts link is to keep the differential centered under the car. Before my last track day I lowered the rear of the car another 1 1/2". After a few sessions on the track I noticed that my tires were rubbing my quarter panels and my tail pipes which meant that in hard cornering the differential was shifting close to 1" from side to side. The watts link should keep this from happening. I will post some pics tommorrow night.

[zamora7]

This from Sam Strano on ls1tech.


This was asked elsewhere, about the rod-ends vs. bushings. At this time, it's rod-end only. This isn't a toy piece and is meant for the best axle to body location. Adding deflection via bushings compromises this, and again, good rod-ends (in this case Aurora or FK, neither of which are junk) aren't noisy like cheap ones.

As for handling. Yes, it's meant for handling improvements. It helps the way the rear acts. With a PHB, which is effective and much better than say a G-body or Mustang 4-link, the roll centers move around depending on which way you are turning. It lowers when you turn left, raises when you turn right. This happens because the PHB is bolted to the axle and the body, but the relationship changes between both in opposite ways as the car moves in different directions. Do you need to autox for this to happen to you? Nope. And FWIW, there have been stock cars Watts Links on them. Even way back in 1978-1985... The Mazda RX7 had a Watts as OEM equipment 30 years ago. But they cost more, which is why you don't see them more (and the fact there are few solid axle cars anymore).

This is a supsension location, and geometry part. It's an improvement from a PHB. It costs more to be sure, but if you can swing it, and find your car acts differently in lefts than in rights and or rubs tires on one side more than the other a Watts can help you out a lot. It won't be for everyone, and in all honesty, I'm not sure what the issue you are having is... but I see Bilstein HD in your sig, and they aren't what they used to be, primarily in the rear. Shocks and springs and all that still matter, and a Watts can't fix a problem that is related to springing or damping.

[killer69]

The watts link and a panhard bar is used to keep your rear end center with the car. The watts is actually better since the rear end stays centered at all times compared to a panhard bar which in hard cornering can still shift the rear end/car to one side. In other words, if your tires are sticky enough the rear end will stay put and the body shifts towards outside of the turn and your tires will rub, like my 4th gen T/A:crying:. Also, if you lower a car with a panhard, you'll need an adjustable one to re-center the rear end or you will need tires real quick.

just woudering how much side to side movement you think there is with a panhard bar? if you are running a 32" long bar that is level at ride height, and you have 3-4" of total suspension travel, how much do you think the rear end is gong to shift 1/4" maybe.
all i have read says if you don't chassis mount the pivot then the entire system is useless.to be perfect the bars should be set level and parellel. then there is the exhaust. yes the roll center is adjustale, so is an adjustable panhard bar
if you are using a panhard bar it better be adjustable. if it has heim joints it will not deflect. and your tires will not rub unless you only have an 1/8" clearance???. there is something to be said about simplicity also, there are a couple cars that run a watts link penny and one lap that do well with it, i think you will find more that run a panhard and do well.. DSE Speedtech, Jakes, just to name a couple that come to mind. not to say the watts is no good but why add 20-30 pounds to your car

my .02

[JRouche]

I have a watts link. I had a pan hard bar, it was WAY to short and there was no way to fit a longer bar under the car. Believe me, I looked high and low to figure out how to make a long bar pan hard work to keep it simple. I just dont have the space.

So the watts link setup was a better option because it occupies some dead space that wasnt being used. A lil close to the fuel cell housing, but some simple clearancing solved that.

I use a frame mounted center pivot (a fayes bellcrank). I made the other parts.

As far as handling goes. I couldnt be happier. And this is before I even played with the adjustments to move the RC. Before I put it in the car felt like it was swimming back and forth over road level changes in a turn. Now I make the same turn and its really solid, the suspension is taking the variations and the body doesnt even get upset at all.

And as far as lateral locating (which what it does) it keeps the rear end centered under all conditions. I have 3/4" clearance between my tire side wall and the inner quarter panel and even under some rough road conditions (vertical movement) and some hard turns (body roll) the tire does not touch the inner pannel. The watts link keeps the housing centered during all of the conditions I have seen.

One of these days I will play with the adjustability of the RC height and see what difference it makes. But so far Im really happy.

Now as far as chassis mounted or rear end housing mounted center pivots go. I like the chassis mounted for a couple of reasons. And both are easy to see.

One is unsprung weight. Chassis mounted puts all the weight on the frame which is suspended with the suspension. A rear end mounted unit places alot of the weight on the unsprung rear end housing. Kinda loads up the rear end and makes it slow. You want to keep the housing as light as possible, it makes it a fast reacting suspension. Too much weight on it makes it heavy and slow (it can over come the shocks). You want it to be light and fast so it travels the road. Keeps the tires planted during fast transitions in the road surface. Thats why independent suspensions are so fast, the main center section is chassis mounted, just half the axle weight and wheel/tire weight (and maybe some bar weight for the roll bar).

Next is the traveling RC height. And to be honest, Im not all that sure how much that will play into the actual feel of the car.

I have driven a couple of cars. And it seems I can get used to the way the car handles. Its always a learning curve if I want to drive it fast and be in control. And control seems to be the selling point with a non-changing RC height lateral device such as a chassis mounted center pivot watts link. The rear RC height will always move with the car, its unchanging.

Where a suspension mounted center pivot will move the rear RC as the cars ride height changes during driving.

And really, as small of the change is I dont think its a point. If you have a race car then yeah, maybe you want to control the rear RC to a T for the ultimate predicability with how the car feels.

But for a steet car I really dont think its a selling point.

Suspensions do SO many odd changes during the travel so I think the slight amount of RC height with a rear end mounted pivot wont be as noticeable for the street car as it might be for a race car. It will just be an aspect of the handling of the car that we all get used to.

Here is a pic of my watts link. JR

https://static1.pt-content.com/images/pt/2009/05/x-1.jpg

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

[Bryce]

I run a watts link in my falcon. I design and built my own with a chassis mounted bell crank.
https://static1.pt-content.com/images/pt/2010/11/tn_full_DSC03443-1.jpg (http://www.motortopia.com/photos/585372)

https://static1.pt-content.com/images/pt/2010/11/tn_full_DSC03444-1.jpg (http://www.motortopia.com/photos/585373)

https://static1.pt-content.com/images/pt/2010/11/tn_full_DSC03445-1.jpg (http://www.motortopia.com/photos/585374)

https://static1.pt-content.com/images/pt/2010/12/tn_full_DSC03454-1.jpg (http://www.motortopia.com/photos/587457)

It is really easy to calculate the lateral translation of a PHB. A 32" PHB level at ride with 2" travel in either direction will move .063, thats 1/16"

If it moves 4" in either direction than you get .251" of lateral translation.

[killer69]

i just had to check, i measured the side to sid movement on our Torque Arm with a 32" panhard bar. 6" of travel 3 up 3 down the axle will move 1/8" of 1 inch or you could just read Bryces post above and get the EXACT measurement to the thousandths of an inch.
our pan hard bar weighs 4.84 lbs that includes the bar the housing mount and the hardware. it also takes 30 seconds to adjust. i am not saying a watts is not better , just not required
Jrouche
that is 10 pounds of suspension in a 5 pound bag lol is it a old prostreet car you ar converting? or are you keeping it a drag car? i can see in your case that a long PHB could be a bitt tricky. is that pic at ride height?

[killer69]

Bryce that is a nice looking peice!!

[Bryce]

Thanks Blake, Since almost every piece of mine is aluminum it only weighs 8.4 lbs.

I calculated it at 3" of travel and its to .141"; close enough to 1/8"; 16 thousands different. HAHA.

[68Formula]

Wow Bryce, it's a shame that'll be hidden under the car!

[LV42DAY]

i just had to check, i measured the side to sid movement on our Torque Arm with a 32" panhard bar. 6" of travel 3 up 3 down the axle will move 1/8" of 1 inch or you could just read Bryces post above and get the EXACT measurement to the thousandths of an inch.
our pan hard bar weighs 4.84 lbs that includes the bar the housing mount and the hardware. it also takes 30 seconds to adjust. i am not saying a watts is not better , just not required

thats what i hear. but then i speak with people with a watts link and they swear they will never go back to a pan hard. apparently that little bit of difference makes all the difference. and after all, every little bit helps.

[LV42DAY]

I run a watts link in my falcon. I design and built my own with a chassis mounted bell crank.
https://static1.pt-content.com/images/pt/2010/12/tn_full_DSC03454-1.jpg (http://www.motortopia.com/photos/587457)

that's beautiful. how much did it cost when it was all said and done? do you have any installed photos of what i looks like?

granted that is pretty thick aluminum, are you not worried the tabs that hold the bell crank will bend after repeated use of hard cornering?

[SIK02SS]

Yes you can use them with leafs.

I have a Fays2/leafs in my car but haven't had a chance to put it to the test yet. Completed install about 2 weeks ago. I have been making suspension changes to my car and documenting results after each change by comparing lap times. I've been told that you can get into the throttle sooner coming out of a corner but we will see.

I'm interested in your results Gaetano! Let me know after you hit the track please

[LV42DAY]

i know lateral dynamics went out of business, but does anyone know someone that used to work there? preferably one of their designers.

i will email Fays2 and ask them if they would like to participate in this thread. help them represent there product so no false accusations are thrown out there.

BMR, has a watts on there torque arm kit for the first gen camaro. theirs is set up with the axle mounted watts link instead of the chassis mounted like the LD or fays2. i will also email them to see if they will take part.

if neither of them want to join in, i will post whatever info they send me back, verbatim.

by making this thread i am trying to seek out those that have actually made the switch to a watts link. there is no better comparison then a before and after on the same car. if all you ever had in your car was a pan hard bar, then how can you speak on what a watts link can do???

trying to keep it factual.

[SIK02SS]

that's beautiful. how much did it cost when it was all said and done?

granted that is pretty thick aluminum, are you not worried the tabs that hold the bell crank will bend after repeated use of hard cornering?

No worries on thickness in that piece. It's plenty strong to hold a lot of force

[Bryce]

that's beautiful. how much did it cost when it was all said and done?

granted that is pretty thick aluminum, are you not worried the tabs that hold the bell crank will bend after repeated use of hard cornering?

Tons of design time by me. Aluminum, about 60 bucks, aluminum Rod ends 40 each, aluminum links 10 each, bushings and fasteners around 20 total axle clamps 70. So about $280. Plus alot of fabrication time. I would say 80-120 hours of design and 40 hours of fab.

[Bryce]

No worries on thickness in that piece. It's plenty strong to hold a lot of force


Thanks and if you look through m build thread (see signature) you will see that it also attaches to the floor and it will have a back up plate inside the trunk.

[SIK02SS]

Thanks and if you look through m build thread (see signature) you will see that it also attaches to the floor and it will have a back up plate inside the trunk.

It really is a great looking piece! I saw the extra holes drilled and figured it was going to have a pretty rigid installation. Did you do this with a mill or do you have CAD/CNC capabilities?

[Bryce]

Sik02SS,

Take a look at my build thread. You might like some of the other things I have built. I used CATIA, a cad program to help with the design of this piece. But everything was cut at home on my bandsaw then hand finished with a die grinder.

[Bryce]

Wow Bryce, it's a shame that'll be hidden under the car!

Thanks 68Formula! I hope it will work as good as it looks!

[JRouche]

Jrouche
that is 10 pounds of suspension in a 5 pound bag lol is it a old prostreet car you ar converting? or are you keeping it a drag car? i can see in your case that a long PHB could be a bitt tricky. is that pic at ride height?

Hahaha.. I know. Too much right? It was in 95 that I decided to put a new rear end housing in the car and Art Morrison was the only company providing the needed parts I wanted. The 62 nova stock is a unibody car, no real frame. So I looked at, and bought their 4-link rear clip. http://www.artmorrison.com/2006cat/33.pdf

It is a lil over kill for this car. 2x4 rails, heavy brackets. Its a rear clip thats good for a 2500hp car that launches hard off the line, which mine is NOT. But I couldnt beat the cost at the time and it really has changed alot over the years.

And no, I didnt buy it to be set up as a pro street car, I always had intentions of making it handle, I just needed a nice set of frame rails to connect everything to. And I dont regret my purchase of the AM rear clip. I DO regret that it took me 15 years to get it on the road and that was because life happened (job change, babies on the way, new house).

Whats nice about having some solid metal back there is I can modify it without worry of stressing the frame rails or brackets.

Its still a parallel 4-link which hasent seemed to cause any problems. The rod ends did. They were large, nice stainless steel poly units and they would actually break free (the jamb nut) because I needed more "twist" than they could handle. So the spherical bearing rod ends went in. They dont come loose now.

It is a busy rear end, all the links. And yes, looks heavy. But the car is light. And the small block really moves the car out. I havent scaled it yet. Im gonna just take a stab and guess the weight is 2800-3000lbs. I have a set of digital race scales, I need to weigh the car just to see where its at. But with a small hp 350 it really takes off, so Im thinking she is pretty light.

And I showed two pics. You asked about if it was at ride height. The first pic is, the one with the solid struts in place for welding the shock mounts. The second pic is with the shockwaves in place but aired down and relaxed. JR

[JRouche]

by making this thread i am trying to seek out those that have actually made the switch to a watts link. there is no better comparison then a before and after on the same car. if all you ever had in your car was a pan hard bar, then how can you speak on what a watts link can do???

trying to keep it factual.

Im a lil lost. You got two examples of a switch. Do you want more or do you think the two examples are not what you were asking for?

You sound a lil perturbed like you arent getting the examples you were asking for. Can you clarify? JR

[Rod]

I'm liking this thread!!

[JRouche]

I run a watts link in my falcon. I design and built my own with a chassis mounted bell crank.
https://static1.pt-content.com/images/pt/2010/11/tn_full_DSC03443-1.jpg (http://www.motortopia.com/photos/585372)

https://static1.pt-content.com/images/pt/2010/11/tn_full_DSC03444-1.jpg (http://www.motortopia.com/photos/585373)

https://static1.pt-content.com/images/pt/2010/11/tn_full_DSC03445-1.jpg (http://www.motortopia.com/photos/585374)

https://static1.pt-content.com/images/pt/2010/12/tn_full_DSC03454-1.jpg (http://www.motortopia.com/photos/587457)

It is really easy to calculate the lateral translation of a PHB. A 32" PHB level at ride with 2" travel in either direction will move .063, thats 1/16"

If it moves 4" in either direction than you get .251" of lateral translation.

Ummm, once again Bryce, SUPER WORK!!!.. I wish I had the welding and design skills that you have. Even a fraction of it would be nice. Any pics of it in the Falcon? Buy the way, I love the old Falcons.

Crazy to see an engineer with great mechanical skills also. Very nice work, JR

[Bryce]

Ummm, once again Bryce, SUPER WORK!!!.. I wish I had the welding and design skills that you have. Even a fraction of it would be nice. Any pics of it in the Falcon? Buy the way, I love the old Falcons.

Crazy to see an engineer with great mechanical skills also. Very nice work, JR

Thanks JR! I wish I could weld that good. But I had a friend (professional welded) do the welding for me. I was a car guy before I was an engineer. An engineer with hands on skills makes a better engineer. Check my build thread in the next few days. Final assembly will happen soon.

[Rod]

:seizure: ARRRGGGGG i want one!!!

https://static1.pt-content.com/images/pt/2011/03/aatn_full_DSC03454-1.jpg

[Bryce]

:seizure: ARRRGGGGG i want one!!!

https://static1.pt-content.com/images/pt/2011/03/aatn_full_DSC03454-1.jpg

I dont think anyone would want to pay me to build one.

[Kenova]

That bracket and bell crank is seriously cool. It kind of throws the "it's heavier than a panhard setup" out the window.
All aluminum!? Dude!

Ken

[Gitter Dun]

I meant to take pic's of my Fays2 watts link and post them awhile back. At my last track day my rear tires were rubbing quarter panels and tail pipes due to rear differential shifting from side to side in the corners so I decided to install a watts link. I also narrowed my tank and re-routed my tail pipes inside of my leaf springs. I haven't had a chance to test this on the track yet but will let you know if if there is an improvement on lap times after my next track day.

https://static1.pt-content.com/images/pt/2011/03/WattsLink101-1.jpg
https://static1.pt-content.com/images/pt/2011/03/WattsLink100-1.jpg
https://static1.pt-content.com/images/pt/2011/03/WattsLink099-1.jpg
https://static1.pt-content.com/images/pt/2011/03/WattsLink098-1.jpg
https://static1.pt-content.com/images/pt/2011/03/WattsLink097-1.jpg
https://static1.pt-content.com/images/pt/2011/03/WattsLink096-1.jpg

[Bryce]

That bracket and bell crank is seriously cool. It kind of throws the "it's heavier than a panhard setup" out the window.
All aluminum!? Dude!

Ken


Thanks Ken. Yep almost all aluminum there are some stainless steel threaded backup plates. and steel fasteners.

[Bryce]

I meant to take pic's of my Fays2 watts link and post them awhile back. At my last track day my rear tires were rubbing quarter panels and tail pipes due to rear differential shifting from side to side in the corners so I decided to install a watts link. I also narrowed my tank and re-routed my tail pipes inside of my leaf springs. I haven't had a chance to test this on the track yet but will let you know if if there is an improvement on lap times after my next track day.

https://static1.pt-content.com/images/pt/2011/03/WattsLink101-1.jpg
https://static1.pt-content.com/images/pt/2011/03/WattsLink100-1.jpg
https://static1.pt-content.com/images/pt/2011/03/WattsLink099-1.jpg
https://static1.pt-content.com/images/pt/2011/03/WattsLink098-1.jpg
https://static1.pt-content.com/images/pt/2011/03/WattsLink097-1.jpg
https://static1.pt-content.com/images/pt/2011/03/WattsLink096-1.jpg


Looks good. I hope to see some lower lap times. I also like the low-profile lock nuts. Thats what I used as well.

[Gitter Dun]

Thanks Bryce. the packaging was really clean and came with a colored instructional booklet. Really top knotch!! Now lets hope it was worth it.

[Ron.in.SoCal]

^ Gae, I'll bet you a beer it was worth it! Before you psoted that I was about to reply saying it looks really stout. Nice job packaging it in there...

[clancj]

should'nt the bars reach from the frame on one side to the axle on the otherside? i dont see how the bars will pull/push when both bar ends are essentially on the axle?

i must be missing something? explain?

[The WidowMaker]

should'nt the bars reach from the frame on one side to the axle on the otherside? i dont see how the bars will pull/push when both bar ends are essentially on the axle?


on a panhard bar, yes. but this is a watts. on a chassis mounted watts, you have a crossmember that ties into the frame on both sides and allows the bellcrank to be mounted in the middle. that point is then stationary and takes the place of the frame rail mount. the two links then travel in either direction from there and mount to the axle. the bellcrank cancels out the lateral movement caused by the links arc.

[clancj]

on a panhard bar, yes. but this is a watts. on a chassis mounted watts, you have a crossmember that ties into the frame on both sides and allows the bellcrank to be mounted in the middle. that point is then stationary and takes the place of the frame rail mount. the two links then travel in either direction from there and mount to the axle. the bellcrank cancels out the lateral movement caused by the links arc.

thanks for watts info. So, i gather its purpose is to keep the axle stationary between the frame rails? (a good thing) If one side were tied to a frame rail, (like a panhard bar) would it function the same? would it also have anti-sway properties (more of a good thing)?

Sorry for all the questions, just try to get a handle on how all these suspension components work.

[Kenova]

I believe Steve Rupp posted a video of Penny's Watts link in action. The video does a good job of illustrating exactly how it all works.
I was surprised at how little the bell crank actually moves.

Ken

[Gitter Dun]

^ Gae, I'll bet you a beer it was worth it! Before you psoted that I was about to reply saying it looks really stout. Nice job packaging it in there...

Thanks bro, yeah, it worked out pretty good. Cant wait to put it to work. I'm glad I've documented my track times with each change or addition I've done to the car. Helps me know if I'm moving forward or not.

[The WidowMaker]

thanks for watts info. So, i gather its purpose is to keep the axle stationary between the frame rails? (a good thing) If one side were tied to a frame rail, (like a panhard bar) would it function the same? would it also have anti-sway properties (more of a good thing)?

Sorry for all the questions, just try to get a handle on how all these suspension components work.

i dont think anybody will ever have problems with questions, and im still learning myself :twothumbs:. its purpose is the same as a PHB, a lateral location device. a watts that is tied to the both frame rails and the center of the axle is known as an axle mounted watts. neither has any anti sway properties. there are pros and cons of both, but both will allow the axle to migrate slightly. it gets more extreme as the roll center is moved away from the axle centerline height. i did some math in the other forum (link at beginning) but those guys dont like math. i need to do some accurate drawings to show my findings.

[Gitter Dun]

thanks for watts info. So, i gather its purpose is to keep the axle stationary between the frame rails? (a good thing) If one side were tied to a frame rail, (like a panhard bar) would it function the same? would it also have anti-sway properties (more of a good thing)?

Sorry for all the questions, just try to get a handle on how all these suspension components work.

No worries on all the questions, this is a great site with alot of knowledgable folk. Yes, the watts link's main purpose is to keep the differential stationary just like a panhard bar. The difference between the two is that the panhard bar is attatched to a fixed location on one side of the car and creates an arc when in motion on the other side of the car. The arc it creates allows for a little bit of side to side differential movement to where the watts link wont. In a correctly installed panhard bar the movement isn't much and I believe the key is to make the panhard rod as long as possible.

I am certainly no expert and would love for anybody else to chime in on this and correct me if I'm wrong.

On your other question, thats a good one. I'm not 100% sure that the chassis mounted bell crank style watts link wont help with a bit of anti-sway.

[MonzaRacer]

On a panhard bar you will have an induced arc, yes it needs to be as long as possible, preferably mounting should run from outside of one frame rail to at least the other frame rail in width. and angularity needs to be low so as to not cause binding points.
BUT you also have to remember the a panhard bar will upset Roll Center, thats the point that the cars left/right balancing point(think corndog stick through car lengthwise) is in the rear.
Quick and dirty the front roll center can be assumed as approximately the camshaft centerline, and this is also the design point we also draw through when figuring suspension too.
but as your car rolls over in turns the side to side shift, while minute may cause instability.
with a watts link there is no bind, no movement side to side and you can raise or lower it to help predict the RC height. Lower, and the car tends to "roll" over or lay over to the inside of the turn, and this tends to make weight transfer and load the inside tire harder. Higher and it will do less rolling thus not loading the tires with top weight but will load more sideways.
Basically the Watts will reduce or eliminate SOME cars need for a stabilizer bar. and it changes shock valving needs.
All in all after many years of NOT understanding the design as I should I finally got it to soak in. My terminology may be off but after seeing suspension video(dont ask i cant remember where I saw it one of those great sites you can never find again) on a suspension sight it explained a lot and let me et a handle on it,,, now I want a watts link in my Monza,,, and maybe my Caprice if I redesign the rear suspension.
Mainly casue a triangulated 4 link doesnt work well with a watts.

[Gitter Dun]

Thanks Lee. I have a question. When I installed the watts link I made sure the rods coming off the bell crank to the axles were level at ride height. If I am to adjust the bell crank up or down they will no longer be level. Can you tell me how this may affect the car?

[Bryce]

Thanks Lee. I have a question. When I installed the watts link I made sure the rods coming off the bell crank to the axles were level at ride height. If I am to adjust the bell crank up or down they will no longer be level. Can you tell me how this may affect the car?

That will have no affect as long as the bell crank does not bind at full suspension travel. The rule for Watts link is the links need to be parralel at somepoint in the travel.

[Bryce]

On a panhard bar you will have an induced arc, yes it needs to be as long as possible, preferably mounting should run from outside of one frame rail to at least the other frame rail in width. and angularity needs to be low so as to not cause binding points.
BUT you also have to remember the a panhard bar will upset Roll Center, thats the point that the cars left/right balancing point(think corndog stick through car lengthwise) is in the rear.
Quick and dirty the front roll center can be assumed as approximately the camshaft centerline, and this is also the design point we also draw through when figuring suspension too.
but as your car rolls over in turns the side to side shift, while minute may cause instability.
with a watts link there is no bind, no movement side to side and you can raise or lower it to help predict the RC height. Lower, and the car tends to "roll" over or lay over to the inside of the turn, and this tends to make weight transfer and load the inside tire harder. Higher and it will do less rolling thus not loading the tires with top weight but will load more sideways.
Basically the Watts will reduce or eliminate SOME cars need for a stabilizer bar. and it changes shock valving needs.All in all after many years of NOT understanding the design as I should I finally got it to soak in. My terminology may be off but after seeing suspension video(dont ask i cant remember where I saw it one of those great sites you can never find again) on a suspension sight it explained a lot and let me et a handle on it,,, now I want a watts link in my Monza,,, and maybe my Caprice if I redesign the rear suspension.
Mainly casue a triangulated 4 link doesnt work well with a watts.

the roll center in dependent on suspension geometry. The Cam centerline is the approximate center of gravity.

The pivot point on a watts link defines the roll center as long as the other suspension link are parralel.

If you transfer more weight you load the outside tire harder.

Im not sure why the wattsl ink would change the need for a sway bar? Roll stiffness is dependent on CG, roll center and spring rates. The panhard and watts could both have the same roll center. therefore the same need for a sway bar.

Why does a tri-4 link not work well with a watts link? If a watts is no bind in vetrical travel then it would work fine with a tri-4

[Gitter Dun]

Thanks Bryce. Now from what I understand, the leaf spring and watts link each define roll center. If thats the case do i want to match roll centers by adjusting bell crank. I have a feeling I want to lower my bell crank so that the center of bell crank is parrallel with leaf spring perch.

[Bryce]

I am not up on my leaf spring geometry but I think on parralel leafs its the front spring eye height that defines roll center. On leafs that converge as they go forward the RC is the height of the convergence point. If you add a watts its now a roll axis.

Im sure someone else could better answer this.

[MrQuick]

partially, but correct.

you have to watch the watts height cause often times an added watts will actually raise the roll center height or not even change it.

Gaetano's just going for tire track locking and adjustability. He's also 2 steps closer to getting his 3 link made.

[The WidowMaker]

That will have no affect as long as the bell crank does not bind at full suspension travel. The rule for Watts link is the links need to be parralel at somepoint in the travel.

correct. people forget that the car is at ride height very little while driving. something is always happening and something is always moving. if it needed to be parallel at ride height it would never be there for long.


Why does a tri-4 link not work well with a watts link? If a watts is no bind in vetrical travel then it would work fine with a tri-4


with a c4l and a watts you have two roll centers. in addition, the bushings must have compliance or a c4l will bind. the watts complicates the movement of the c4l and can induce even more bind. running rubber bushings usually solves this issue.

[MrQuick]

Tim, would you know at what point of travel a converged 4 link would bind?

vince

[Bryce]

A C4L is always in bind; it's an over constrained system, that is why it needs a compliant bushing. What I was saying is a watts would not add more bind to an already bound system.

With compliant bushings or heim joints the suspension can articulate around 6 degrees. That is plenty for these cars.

[AMC Racer]

Why is a C4L over-constrained? There are 6 degrees of freedom with a solid axle rear axle suspension so you need 4-links to constrain the axle movement to get just 2 degrees of freedom of jounce (up & down) and roll. More than four links is over-constrained. A link by definition is free to rotate about it's pivot point and can only take loads along its axis. Limiting freedom of movement at the link pivots constrains the system so causes bind and bending in the link, e.g. fitting rigid bushings or bushings with limited compliance. Proper selection of bushing material is needed to minimize constraint in the system or use sphericals (heims).

A C4L has 4 links so is not over constrained. A parallel 3-link with watts or panhard has 4 links so is not over constrained. A parallel 4-link with watts or panhard has 5 links so is over constrained. Adding a watts or panhard to a C4L adds a 5th link so over constrains the system. I've done layouts of various link suspensions and all will bind in roll if the links aren't free to rotate at the pivots. In most cases the amount of movement at the pivot is small, so the bushings don't need much compliance. Some link suspensions using particularly short links (i.e. Mustang) need significant link movement to accommodate roll so tend to bind - particularly if fitted with relatively rigid bushings.

A properly designed C4L will accommodate much more than 6 deg. roll and should keep the axle centred in jounce without the need for secondary lateral control.

[parsonsj]

A C4L suspension is over-constrained because the links aren't parallel. Bryce already said it, but I'll say it again: without compliant bushings, brackets and control arms, the C4L would allow zero roll.

jp

[AMC Racer]

Do the links in a parallel link system stay parallel in roll? Must be missing something as the layouts I've done show all systems need freedom of movement at the link pivots or you get zero roll, i.e. it's not an inherent issue just with the C4L? :confused:

[parsonsj]

Do the links in a parallel link system stay parallel in roll?Of course. The brackets move with the rear end housing, so the links remain parallel: both top to bottom and left side to right side. A parallel link 4 link (more commonly called a 4 bar) is only limited by the joint articulation. Compare that to a C4L: the links aren't parallel in either plan, side, or front/rear view. As a C4L suspension rolls, the linkage arms need lengthen/shorten to allow for roll. As others have noted, a small amount of compliance will allow enough roll for passenger car usage.

jp

[AMC Racer]

Thanks. Will give the parallel link layout another try ... couldn't get it to roll without modelling link ends as sphericals and 4bar needed to remove one of the forward links (i.e. make it a 3 link with watts). :confused: The T4L seemed to roll fine - the axle just moves fore/aft slightly and rotates slightly to accommodate the roll. By fine tuning link lengths and angles could minimize the axle movement.

[Twentyover]

.............Im not sure why the wattsl ink would change the need for a sway bar? Roll stiffness is dependent on CG, roll center and spring rates. The panhard and watts could both have the same roll center. therefore the same need for a sway bar.



First, my understanding is that a watts imposes it's roll center loation on a car as a C4L has compliant bushings, leaf springs bend and twist, etc..

If you use the watts to move roll center height close to CG, there will be very little roll, mitigating the need for an antisway bar. Not suggesting this is a desireable design, but say you use a mumford link (similiar in concept to a watts, but can move the roll center below ground on a live axle car) with the RC at ground level, it would require a bigger rear bar because the moment arm between RC and CG is greater.

[The WidowMaker]

Tim, would you know at what point of travel a converged 4 link would bind?



that depends on lots of factors. others have discussed how its possible in roll, but its also possible in bump and rebound. i first realized this when i had poly bushings and took the shocks off the rear on the chevelle. before anything made contact, the rear suspended itself because of the bind.

hard to explain in type, but think about it this way. if your uppers converge at 45*, are 17" in length, have mounts that are narrower at the axle and they are built to be parallel to the ground at ride height we get a few numbers. first, the axle is 12" away from the upper frame mounts and the axle mounts are 24" closer together than the frame mounts (12x2). now, the further we extend the length of the upper control arm, keeping the angle constant, the closer together the axle mounts would need to be. the shorter we make the upper control arm gets us the opposite effect. so, at ride height our arms are parallel to the ground and the axle is the furthest from the upper frame mounts in plan view. as we raise or lower the rear, we decrease the distance between the frame mount and the axle mount requiring that either the frame mounts narrow, the axle mounts widen or the angle changes. since neither of the first two can happen, we rely on bushings to allow the arms to change angle and keep us from binding.

think about this another way. take the same numbers from above and attach your upper control arm to only the frame mount and let the axle end drop. it will hang straight down from the frame. pick the axle end up until its parallel to the ground and the axle end will move inboard 12". that requires compliance from the bushings.

[AMC Racer]

Double-checked models of 3-link, 4 Bar and Triangulated (or converging) 4-link:
- zero compliance model (zero deformation permitted in any links, chassis, etc.)
- spherical joints in link ends and mating chassis and axle points (links are free to swivel but no translation allowed)

4-Bar with Watts:
- parallel, equal length links
- will roll freely when watts links are parallel to each other and perpendicular to the watts crank
- binds in combined bump & roll when watts roll centre moves away from 4-bar centre
- links do not remain parallel in roll, but do keep symmetry
- unequal length links or non-parallel links will not roll freely without compliance (links need to translate as well as swivel)

Triangulated 4-link (converging 4-link):
- tested converging uppers, converging lowers, both converging
- all behave similarly
- full freedom in roll & jounce - ZERO BIND (contrary to conventional wisdom)
- requires swivel joints in links for total freedom in roll and jounce

3-Link with Watts:
- full freedom in roll within normal limits, ie. normal limits of Watts

In all cases, using bushings instead of swivels (heims or similar) causes restraint so bind. Link length and geometry is a significant factor in the amount of swivel required at the link ends. Typical OEM T4L geometries can require more swiveling of the links for free movement, so with bushings may bind at low roll angles or limited bump/droop (likely the reason the T4L has the reputation for binding) ... however, kinematically the T4L is free in roll, bump and combined movements when links have swivels. Rigid urethane bushings are likely a poor choice.

Hope this helps.

Triangulated 4-link in roll video:
http://s41.photobucket.com/albums/e273/RedDevil401/?action=view&current=RearT4Lnobindinroll.mp4

4-Bar (Parallel, equal length 4-link with Watts) in roll video:
http://s41.photobucket.com/albums/e273/RedDevil401/?action=view&current=Rear4-bar-rollnobump.mp4

4-Bar (Parallel, equal length 4-link with Watts) in combined bump & roll - note side movement when link is removed (suspension was in bind):
http://s41.photobucket.com/albums/e273/RedDevil401/?action=view&current=Rear4-barbump.mp4

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

[The WidowMaker]

binds in bump or droop when watts roll centre moves away from 4-bar centre


im not sure i follow you here. is this bump or droop with roll as well? if so, your model may be reporting binding if it does not not allow for axle migration. there is side to side movement with both style watts links. there is no binding with with regular bump and jounce.

[AMC Racer]

Sorry, yes ... the "bump" shown is combined bump and roll. With pure bump or droop or pure roll, the 4-Bar & Watts linkage moves freely ... but combined bump and roll needs compliance. Updated post to clarify.
Thanks!

[JRouche]

Umm? Can I pipe in. I have used the pan hard bar in my car. It was an art morrison setup. Looked to be more for strait line driving. Like 1/4 mile cars, or pro-street cars.

Not good for street driving. Its a proper four link setup. Plenty of bind. It would lossen up the jamb nuts on the links just to get more travel. Not good.

So I swapped out the stainless steel (nice) rod ends that were poly ends for some decent qa1 spherical ends. Capped them off with some covers and Im hoping they will survive.

Now I can get a good 5-6* of body rotation and the ends dont bind. It sucks to have to go through this amount of work and money. But its my fault. Back in the mid 90s I didnt know what the plan was, and really, pro-street cars were the ticket. Now that I know better (and have more options) handling is higher on the ticket. I have a watts link. Along with it and the new rod ends and some decent roll bars the car is scary fast in the turns.

Its nice to drive AROUND a newer honda when Im on the outside lane. Kinda funny seeing a 1962 nova driving around a new light honda. Its fun. JR

[SIK02SS]

problem with putting covers/boots over rod ends, is once dirt and grime finds its way into them (which it will), it's stuck in them.

also, rod ends have different strengths, do you know what yours are? Hopefully XMR or better..and over time rod ends wear out, especially on street cars with high use, meaning they'll get very loud (clunky) and need replacing...but yes, they are bind free if installed properly :)

another bind free and quiet option are roto joints. UMI sells roto joint items..

[NewSpin]

I know this thread is a bit old, but i'm curious about the Watt's link kit for my '71 Nova
and a friend is curious for his '75
what was the final conclusion? Was is worth it?
I recently sold a Chassisworks triangulated 4-link I was never able to install, but I'd be open to keeping leafs and adding a Watt's link kit if it will really do the job.

[BMR Sales]

I know this thread is a bit old, but i'm curious about the Watt's link kit for my '71 Nova
and a friend is curious for his '75
what was the final conclusion? Was is worth it?
I recently sold a Chassisworks triangulated 4-link I was never able to install, but I'd be open to keeping leafs and adding a Watt's link kit if it will really do the job.

I don't think there is much benefit of a Watt's Link unless you get rid of the Leafs.

We make a Torque Arm w/ Watts Link for Novas & Camaros

Here the Watts Link that we just put in my '73 Camaro

https://static1.pt-content.com/images/noimg.gif (http://s24.photobucket.com/user/TractionControl/media/posted/73Camaro/_MG_2959_zps6qm10j8c.jpg.html)

Here's how a Watts Link works

https://static1.pt-content.com/images/noimg.gif (http://s24.photobucket.com/user/TractionControl/media/posted/73Camaro/Watts_linkage_zpsyrqpxqwv.gif.html)

[F-Body International]

I know this thread is a bit old, but i'm curious about the Watt's link kit for my '71 Nova
and a friend is curious for his '75
what was the final conclusion? Was is worth it?
I recently sold a Chassisworks triangulated 4-link I was never able to install, but I'd be open to keeping leafs and adding a Watt's link kit if it will really do the job.

Update to heavy duty leaf shackles/bushings and you should have less lateral flex.

[NewSpin]

I've already got heavier multi-leafs on my car, I knew how it worked I was just wondering how this particular kit worked out for the OP.
BMR that looks pretty snazzy, is it bolt-on?

[F-Body International]

I've already got heavier multi-leafs on my car, I knew how it worked I was just wondering how this particular kit worked out for the OP.
BMR that looks pretty snazzy, is it bolt-on?

Yes, their kit is bolt-on. Most other link suspension kits require welding at some point.

[BMR Sales]

I've already got heavier multi-leafs on my car, I knew how it worked I was just wondering how this particular kit worked out for the OP.
BMR that looks pretty snazzy, is it bolt-on?

Yes, that is all Bolt-On