G-Body guys ... Watt's Link !!!

[RobG]

Originally Posted by JRouche

Looking good!! I am in the process of moving my coilovers from the rear position on my four link to accommodate the watts. I have all the parts for the watts now, thanks to Tim at Fayes and Marc at SC&C, thanks guys.

My question is how or where are you gonna locate the pivot point for the center pivot? How are you gonna determine where to set it? Is there a formula that you will go by or seat of the pants driving to adjust the RC? JR

Well, in my frame I tried to get everything as centered as possible. The cradle, the axle brackets and then the propeller. The propeller needs to be at about a 10 o'clock and 5 o'clock position for proper articulation, it can't be straight up and down. I hope that helps a little.

[deuce_454]

Originally Posted by RobG

The propeller needs to be at about a 10 o'clock and 5 o'clock position for proper articulation, it can't be straight up and down.

dude... step back away from the keyboard....

When setting up the watts, only two things are super critical... (assuming everything is installed correctly)

1. the two arms need to be exactly!! the same length, i say this because on the fays setup they are adjustable.... you cant use them to offset the axle to one side.. as the lengths wont be identical and axle wont stay centered....

2. when you have the car at rideheight set the propeller straight up and down and clamp the axleclamps so both arms are exactly!! level...

after this you can adjust the propeller up or down to tweak the rollcenter as needed, WITHOUT changing the length of the watt-link arms or the position of the axleclamps... the clocking of the propeller isnt overly critical... it will allow ample traven in both directions if its about vertical at rideheight... 5 and 11 o-clock wont hurt or help compared to 6 and 12,

be warned that on a g body the conflicting rollcenters (intersection of UCA´s and the fixed watts propeller) adds roll resistance, so when you think you are only moving rollcenter and keeping sway bar setting same... the resistance to roll will actually increase when you move the propeller downwards... this is especially true if you are running polyurethane upper bushings in the rearend... (UMI solid upper bushings will break somthing as you need the compliance of the elastomer bushing)

[Marcus SC&C]

Okay let`s clear things up a little bit here. First off it`s best to run compliant rubber bushings in the axle housing if you plan to run a watts. Let the watts handle the lateral axle location and RC locating duties and just let the UCAs handle controling pinion angle. Beefy arms are fine just use compliant bushings in the axle housing. It will work with poly in the housing but run the watts in one of it`s 3 highest settings to prevent RC conflict. As far as running the watts with beefy upper arms AND hard bushings or bearings in the axle housing, just don`t do it. It`s dumb.
PS. Lowering the rear RC with the watts actually requires a big increase in rear spring or swaybar rate. That`s one reason we designed the watts and Spohn adj. rate rear bar to work together. I still prefer to run the watts relatively high, 16" or so. We haven`t seen any measurable gains from lowering it much more and it requires an uncomfortable increase in spring rate and sway bar rate to keep the car neutral. Been there,done that. Mark SC&C

[ProTouring442]

Originally Posted by Marcus SC&C

Okay let`s clear things up a little bit here. First off it`s best to run compliant rubber bushings in the axle housing if you plan to run a watts. Let the watts handle the lateral axle location and RC locating duties and just let the UCAs handle controling pinion angle. Beefy arms are fine just use compliant bushings in the axle housing. It will work with poly in the housing but run the watts in one of it`s 3 highest settings to prevent RC conflict. As far as running the watts with beefy upper arms AND hard bushings or bearings in the axle housing, just don`t do it. It`s dumb.
PS. Lowering the rear RC with the watts actually requires a big increase in rear spring or swaybar rate. That`s one reason we designed the watts and Spohn adj. rate rear bar to work together. I still prefer to run the watts relatively high, 16" or so. We haven`t seen any measurable gains from lowering it much more and it requires an uncomfortable increase in spring rate and sway bar rate to keep the car neutral. Been there,done that. Mark SC&C

Good info! I do not have a G-body, but rather an A-body (72 442) and was thinking of a Watts, factory style lower arms, and a torque-arm. Any thoughts on this?

Shiny Side Up!
Bill

[JRouche]

Originally Posted by Marcus SC&C

Okay let`s clear things up a little bit here. First off it`s best to run compliant rubber bushings in the axle housing if you plan to run a watts. Let the watts handle the lateral axle location and RC locating duties and just let the UCAs handle controling pinion angle. Beefy arms are fine just use compliant bushings in the axle housing. It will work with poly in the housing but run the watts in one of it`s 3 highest settings to prevent RC conflict. As far as running the watts with beefy upper arms AND hard bushings or bearings in the axle housing, just don`t do it. It`s dumb.
PS. Lowering the rear RC with the watts actually requires a big increase in rear spring or swaybar rate. That`s one reason we designed the watts and Spohn adj. rate rear bar to work together. I still prefer to run the watts relatively high, 16" or so. We haven`t seen any measurable gains from lowering it much more and it requires an uncomfortable increase in spring rate and sway bar rate to keep the car neutral. Been there,done that. Mark SC&C

Hey Marc, great info. And I hate to hijack this thread. But I have a couple questions. The pivot point for the propeller. Can you steer me to a good description of a baseline to start with to weld it in. I have read up on roll center and I "kinda" get it, still kinda baffling. I gotta try and wrap my mind around that issue.

What I have is a AME 4-link, poly bushed Air Ride tech shockwaves. The car is a light 62 nova. Im just trying to determine the correct location, height wise to mount the adjustable plate for the propeller. I have as much room up and down that I need. Im just lost as to where a good starting point would be. Centered on the axle housing with equal amounts of adjustability up or down? A lil lower, a lil higher??

And the spring rate issue you talked about? With these air springs Im kinda stuck. I think they are fairy progressive in spring rate, being an air spring.

Dont mean to be a pest, or to hijack this post (sorry). Any help would be gratefully appreciated. Thanks... JR

[The WidowMaker]

figure out where your stock RRCH was, and dont put an adjustment at that height. you should have 5" or so of adjustment, so if you get a range of 12-17" you would be golden. some guys are running them around 10, but like mark said, the coresponding rates would have to be really large.

a good starting pt is equal or just above the rear axle centerline.


deuce - good pt about the bars being equal and also about setting the arms level. they dont have to be level (just equal and opposite), but that makes it more complicated to set up.

Tim

[deuce_454]

the stock RRCH is alittle funky to find.. it is at the theoretical intersection of the rear UCA's .. on a non lowered car about 6 inches behind and 6 inches above the center of the rear end... on a lowered car its somwhere in the trunk!

i have mine set at axle center and it works awesome, i havent recieved the adjustable swaybar from markus yet... but he assures me that its on its way, so íll be able to play arround with RRCH and swaybar rate to find the sweetspot...