Results 1 to 16 of 16
  1. #1
    Join Date
    Sep 2006
    Posts
    207
    Country Flag: United States

    watts link clarification

    Using a watts link on my setup on a 1968 Impala. Rear suspension is a factory 4 link style setup. My question comes at the addition of a sway bar. Is it customary to run the watts link with a sway bar?

    setup:
    global west custom lower control arms for air ride. umi tubular uppers not adjustable. fays 2 watts link.

    Thanks for the help,
    D

  2. #2
    Join Date
    Oct 2007
    Posts
    1,734
    NO a sway bar and a watts link are not common..
    From a place you will not see comes a sound you will not hear....

    67 Camaro In progress

    https://www.pro-touring.com/showthre...-Tap-67-camaro

  3. #3
    Join Date
    Apr 2009
    Location
    Michigan
    Posts
    155
    Country Flag: United States
    I agree that it's not particularly common to see both, probably because there's usually not a lot of extra real estate available for a nice sway bar setup when you add a watts link into the mix. With a watts link, you can raise the roll center height easily, which can negate the need for a sway bar, but that comes with undesirable side effects.

    If it were up to me, I'd run both a sway bar and a watts link if you have that option. Keeping the sway bar will let you get away with a lower spring rate and a lower roll center height for better grip in bumpy corners. Plus, the lower spring rate will give you a better ride.
    - Ryan

  4. #4
    Join Date
    Apr 2007
    Posts
    170
    If you want a Watt's link with a lower roll center then you re-configure the center link and it becomes a Mumford link

  5. #5
    Join Date
    Aug 2004
    Location
    Austin, Tx
    Posts
    452
    Country Flag: United States
    I don't know about customary, I don't think that a lot of cars run a Watt's link, but the two serve different purposes and are complementary. So I would use both if you and are after performance and tunability.

    The Watt's link primary purpose is side-to-side location with the secondary benefit of rear roll center height control.

    The sway bar is there to help control roll/body lean, and with adjustable arms is yet another tuning tool.

    I have both on my car (71 Firebird). A good bit of work went into packaging the bar install. There's not a lot of room back there but it certainly can be done.
    Bryan (a.k.a. Carbuff)

    70 Camaro RS Hunk'o'Metal - Previous Project
    71 Firebird Project T.O.W. - New Project

  6. #6
    Join Date
    Jun 2012
    Location
    Chicago burbs
    Posts
    158
    Country Flag: United States
    Quote Originally Posted by carbuff View Post
    I don't know about customary, I don't think that a lot of cars run a Watt's link, but the two serve different purposes and are complementary. So I would use both if you and are after performance and tunability.

    The Watt's link primary purpose is side-to-side location with the secondary benefit of rear roll center height control.

    The sway bar is there to help control roll/body lean, and with adjustable arms is yet another tuning tool.

    I have both on my car (71 Firebird). A good bit of work went into packaging the bar install. There's not a lot of room back there but it certainly can be done.
    ^^^My thoughts exactly. I set up my 69 442 with the hellwig bars front and back and loved the improvement. Then I installed the Fays2Watts. The addition of the Watts was primarily to prevent the axles lateral shift allowed by the triangulated 4 link, but soon found that the adjustable roll center allowed me to tune the car's under/oversteer with a single 3 minute bolt change.

    For what it's worth, Ive never adjusted the rear bar, I set it to SC&C's recommended hole and use the watts for tuning.

    1969 442 6.0L LQ9 T56
    Fab9 w/ custom 3 Link conversion
    FAYS2 Watts link
    Thanks to Mark at SC&C for his honesty and passion for the sport, and Ron Sutton for the wealth of knowledge that has helped shape so many of the cars on this site.

  7. #7
    Join Date
    Aug 2012
    Location
    Peoria, AZ
    Posts
    1,648
    Country Flag: United States
    First off, I suggest you watch this video of a 4 link suspension and what happens when a watts links added.

    https://youtu.be/EDM9_-4kjHg

    The only way to NOT restrict travel is to use super compliant rubber bushings at all control arm mounting locations. I know some have been happy with this compromise, I just never could get past it once we did the test shown in the video.
    Lance
    1985 Monte Carlo SS Street Car

  8. #8
    Join Date
    Apr 2009
    Location
    Michigan
    Posts
    155
    Country Flag: United States
    Quote Originally Posted by SSLance View Post
    First off, I suggest you watch this video of a 4 link suspension and what happens when a watts links added.

    https://youtu.be/EDM9_-4kjHg

    The only way to NOT restrict travel is to use super compliant rubber bushings at all control arm mounting locations. I know some have been happy with this compromise, I just never could get past it once we did the test shown in the video.
    Excellent video, thanks for sharing. Makes you wonder how much of the rear roll-stiffness tuning people do with a watts link is actually due to roll center height change vs introducing / removing bind during articulation.
    - Ryan

  9. #9
    Join Date
    Aug 2004
    Location
    Austin, Tx
    Posts
    452
    Country Flag: United States
    Quote Originally Posted by stab6902 View Post
    Excellent video, thanks for sharing. Makes you wonder how much of the rear roll-stiffness tuning people do with a watts link is actually due to roll center height change vs introducing / removing bind during articulation.
    Lance can correct me if I'm wrong, but I think the issue demonstrated in that video is specific to the 4-link. The 4-link itself is working to keep the axle centered, or at least under control (as it appears to move quite a bit without the Watt's). Thus the 4-link is fighting with the Watt's link unless their roll center heights are matching. When the bellcrank was lowered, the roll center heights were very different and were in contention.

    On a 3-link or other suspension that doesn't have another means of side-to-side location, you wouldn't have that type of binding.
    Bryan (a.k.a. Carbuff)

    70 Camaro RS Hunk'o'Metal - Previous Project
    71 Firebird Project T.O.W. - New Project

  10. #10
    Join Date
    Apr 2009
    Location
    Michigan
    Posts
    155
    Country Flag: United States
    Quote Originally Posted by carbuff View Post
    On a 3-link or other suspension that doesn't have another means of side-to-side location, you wouldn't have that type of binding.
    I totally agree. I was referring to the triangulated 4 link cars we've been discussing in this thread (GM A, G, and B-bodies).

    - Ryan


  11. #11
    Join Date
    Aug 2012
    Location
    Peoria, AZ
    Posts
    1,648
    Country Flag: United States
    Look at it this way, the only way a watts link will work without binding on a triangulated 4 link setup is if the roll center on the watts is very close to the roll center of the 4 link. When you consider that...what's the sense of even putting a watts link in then?
    Lance
    1985 Monte Carlo SS Street Car

  12. #12
    Join Date
    Sep 2010
    Location
    Beach Park IL
    Posts
    2,405
    Country Flag: United States
    B bodies aren't triangulated enough to call them triangulated, they have a panhard bar stock.

    To the OPs question: Rear sway bars or anti roll bars are tuning tools. The need for an ARB is independent of what type of lateral locating device you are using on your rear axle.
    Donny

    Support your local hot rod shop!

  13. #13
    Join Date
    Apr 2009
    Location
    Michigan
    Posts
    155
    Country Flag: United States
    Good point Donny. I had the later B-bodies in mind. I think 1971-1996 were triangulated with no panhard bar.
    - Ryan

  14. #14
    Join Date
    Aug 2012
    Location
    Peoria, AZ
    Posts
    1,648
    Country Flag: United States
    Quote Originally Posted by dontlifttoshift View Post
    B bodies aren't triangulated enough to call them triangulated, they have a panhard bar stock.
    Thanks Donny, I did not know this...
    Lance
    1985 Monte Carlo SS Street Car

  15. #15
    Join Date
    Feb 2013
    Posts
    523
    Country Flag: United States
    The LCA's are parallel enough for these cars that it's a common anti-sway bar mounting point. I looked but unfortunately don't have a clear picture of the rear suspension at the moment.
    Here it is:
    Name:  rear axle.jpg
Views: 63
Size:  147.0 KB
    Last edited by JustJohn; 04-07-2020 at 12:24 PM. Reason: added pic

  16. #16
    Join Date
    Jun 2012
    Location
    Chicago burbs
    Posts
    158
    Country Flag: United States
    Quote Originally Posted by SSLance View Post
    Look at it this way, the only way a watts link will work without binding on a triangulated 4 link setup is if the roll center on the watts is very close to the roll center of the 4 link. When you consider that...what's the sense of even putting a watts link in then?
    A quick observation on that really nice vid is that this situation is worsened if the car is lowered(roll center moves into the trunk, or if you have antisquat relocation bars(combined moves it reallly high in the trunk).

    I have about a years worth of driving while running the triangulated 4 link and the watts installed simultaneously before I burned in a 3 link setup. Below are some of the pro's and cons I noticed.

    Pros:
    Lateral stability improvement was massive. When you dip into a corner with the stock triangulated 4 link, the body shifts, then the axle, then they play a small round of ping pong before stabilizing, which makes each corner a guessing game. The watts addition made jumping into corners so much more stable. I should mention by this time I was alreayd running SC&C stage 2 up front. I also had an issue with rubbing 295's because the axle was shifting over 3/4 '', which was cured by the watts.


    Cons:
    Two Roll centers. As you move the roll center down on the watts to gain more rear traction, it fights the roll center defined by the upper arms(this is confirmed by the video Lance linked(thanks btw). Usually, protouring cars don't run more than 3 or so inches of travel, so it's uncommon for the axle to articulate so much you start putting twist into the frame. Well. at least for most positions of the watts bolt-when I ran mine all the way down on the street and drove aggressively I noticed that before mid corner the rear end would bind, then unbind sometimes later. Really not a great feeling, but those lowest settings really shift the car heavily into Understeer, so the nice balance is up near the middle anyways.

    After about a year, I converted the rear to a 3 link. although the fighting roll centers definitely played a role in the decision, I also wanted to adjustable antisquat, and new gears and a bunch of other stuff.

    MY experience with it, knowing what I know now...if I couldn't add the 3 link, I would still add the watts, just for the stability it provided and a way to control the roll center to create a more favorable roll axis.

    again, this is just my experience with using this setup for a while, hope it comes across that way.

    Your Quarantine Pal,
    Scott

    1969 442 6.0L LQ9 T56
    Fab9 w/ custom 3 Link conversion
    FAYS2 Watts link
    Thanks to Mark at SC&C for his honesty and passion for the sport, and Ron Sutton for the wealth of knowledge that has helped shape so many of the cars on this site.