G Body bolt in Watts Links done!

[Marcus SC&C]

The bolt in G Body watts is done and shipping. There`s been talk about it on and off for a while now but after much testing and tuning it`s done and we`re really happy with it! First a few basics. Technically the triangulated 4 link factory suspension already locates the rear axle laterally and defines the roll center so a watts link shouldn`t be needed. However the factory suspension does a very poor job at both. The rear axle can move a great deal laterally (up to 1" to each side!) and efforts to reduce lateral movement have a tradeoff in increased binding and ride quality. Arms like the Currectracs are a very good compromise but they`re still a compromise. The roll center of the factory suspension is too high and migrates both vertically (a LOT!) and laterally. Combined with lateral axle movement and roll steer this makes for a very unpredictable rear suspension that`s hard to drive fast. We partnered with Fays2,the industry leader in watts link packages to design one that would compliment the factory suspension. The watts locates the rear axle laterally with almost surgical precision. It stays perfectly centered at all times, period. It also defines and dominates the roll center. Initially we had concerns about having conflicting roll centers but testing has shown that as long as the watts is run with the roll center in roughly the same neighborhood that the stock one roamed around in that the results are nothing but positive. We recomend rubber UCA bushings in the axle housing to allow plenty of compliance. The result is that we can still lower the RC several inches on a lowered car and we can keep it right there. Because it`s a frame mounted watts the rear moment arm (from CG to RC) always remains exactly the same length also. The end result is that the rear suspension now feels linear for the first time and all of the "squirm" is gone! The watts has a general calming effect on the suspension. We had one client say that the car felt slower with the watts installed. We asked him to try the same turns again but note his speed vs. his speeds without the watts and he was suprised to find he was going much faster! The watts made the car so much easier to drive at speed it didn`t feel like he was driving as fast. Comments like that let us know we`re doing our job! :)
We`re also working on one for A body which is a much bigger challenge. We`ll probably have one out for A body ElCamino and station wagon in a short time. A body coupes will take some serious re engineering to package in the small space they have but we`re dedicated to getting it done. In the mean time, the G Body guys finally got something before the A body guys did. :cool:
Here are a few pics of preproduction units installed. Note the first 2 pics are shown at full droop. The last pic (a Camaro) shows what the links look like at ride height. Mark SC&C

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[Samckitt]

How does this work with factory over the rear style exhaust?

[project hotrod]

Rock on.

Marcus,

At some point in time I would like to discuss using this or the universal with a 3 link set up in a G-body.

The universal watts may need to be used depending on what I do with the rear frame rails and the car will also have a 9 inch.

[The WidowMaker]

cant wait to see what you come up with for the A body. i dont think its going to fit mine, but we'll have to see.

[ScotI]

..... The result is that we can still lower the RC several inches on a lowered car and we can keep it right there.

What does one consider "a lowered car"?

I've set my G-bodys up with > 3" drops which I think is more than typical. For the car I have now, I'm wanting it as low as my previous cars w/o the compromises (dropped spindles up front & cut coils in back).

I want to make this car as stable as a new car would be engineered. I purchased the Currie arms from you & relocation brackets so I should be off to a good start but I'm not sure what to expect & hopefully this Watts set-up will help.

[rq375]

will it work with 3" exhaust and Monte tails?

[Samckitt]

will it work with 3" exhaust and Monte tails?
X2?

[Marcus SC&C]

Since the watts in vertically adjustable clearance changes with setup. Overall it`s pretty good though. Generally almost any tail pipe will fit on the side with the low link. The other side can cause fit issues with prebent pipes. The good part is that there is room there, the tail pipes may just have to be modified on that side. On our Stage 2 test car the 442 style drivers side pipe hit the link but changing the radius of the pipe took care of the problem and they fit good now. 3" will be tight on that side but there is room for them.

Project hotrod, we`re putting one on our G5/3 link car now (the FabFit). It`s a no brainer. I expect it to work even better than the super long panhard bar that`s on there now.

ScotI, I mentioned that because as G bodys are lowered the RC goes up even more than stock. I don`t recomend using the watts to drop it dramatically because off the shelf springs and swaybars won`t work well anymore. But if a stock G body rear RC is 19" and a lowered one`s is 21" (higher than the CG at this point and it could jump to as much as 23" at full bump) we can drop it to say 16"-17" stabilize it and keep it there under all conditions. That might not sound like a lot at first but it is when you think about it and the difference in actual performance and drivability is very impressive. Mark SC&C

[project hotrod]

Project hotrod, we`re putting one on our G5/3 link car now (the FabFit). It`s a no brainer. I expect it to work even better than the super long panhard bar that`s on there now.



From my research a watts link seems better than a panhard by far.

And, I didn't know your G5 car had a three link it. Way cool.

One thing that concerns me is RC propagation as the vehicle is lowered which you mentioned in this thread. My goal is the standard 4.5" to 5" static ride height.

[ScotI]

......One thing that concerns me is RC propagation as the vehicle is lowered which you mentioned in this thread. My goal is the standard 4.5" to 5" static ride height.
As measured from the bottom of the frame rail?

[project hotrod]

As measured from the bottom of the frame rail?

Real world, that is what I would like. But it depends on the front crossmember. I can't remember if it is that much lower than the frame rail from my last g-body. And, I don't pick up the new car
next weekend.

At this point it's safe to assume the front crossmember will receive
some modification for clearance of the LSx pan.

Overall the plan is to have the car as low as possible.

[Marcus SC&C]

4.5"-5" from the frame rails in front of the rear tires to the ground? I just measured two G bodys we have in the shop with Hotchkis and SPC Performance springs and they`re closer to 7" at that location. Real world, 2.5" more drop will ruin the rear suspension geometry and leave you with no usable bump travel. The car tucking 285-40-17 rear tires only has 1.5" of tire clearance in bump so 2.5" is out for sure on that car. Super low looks cool but it very seldom works cool unless the chassis was specially built. The watts will allow for about another inch of rear drop than normal for a total of about 2" but even that adds more compromise to the geometry. Don`t get too fixated on ride height. Work out the height the car will work best at then tweak the cars stance around that. Mark SC&C

[project hotrod]

4.5"-5" from the frame rails in front of the rear tires to the ground? I just measured two G bodys we have in the shop with Hotchkis and SPC Performance springs and they`re closer to 7" at that location. Real world, 2.5" more drop will ruin the rear suspension geometry and leave you with no usable bump travel. The car tucking 285-40-17 rear tires only has 1.5" of tire clearance in bump so 2.5" is out for sure on that car. Super low looks cool but it very seldom works cool unless the chassis was specially built. The watts will allow for about another inch of rear drop than normal for a total of about 2" but even that adds more compromise to the geometry. Don`t get too fixated on ride height. Work out the height the car will work best at then tweak the cars stance around that. Mark SC&C


Would you mind discussing this a little further via PM?

I'd like to keep this thread on track, and also not let a few things about my combination out of the bag just yet. :naughty:

[GBodyGMachine]

No Way. Its Finally Done! Yeah

[Marcus SC&C]

PH, sure PM away or better yet e mail me. I check e mail several times a day but don`t get the time to check PMs everyday on every forum we sponsor. Mark SC&C

[project hotrod]

PH, sure PM away or better yet e mail me. I check e mail several times a day but don`t get the time to check PMs everyday on every forum we sponsor. Mark SC&C

Sounds good.

I assume the tech addy in your sig is the one I use?

[jackfrost]

ScotI, I mentioned that because as G bodys are lowered the RC goes up even more than stock. I don`t recomend using the watts to drop it dramatically because off the shelf springs and swaybars won`t work well anymore. But if a stock G body rear RC is 19" and a lowered one`s is 21" (higher than the CG at this point and it could jump to as much as 23" at full bump) we can drop it to say 16"-17" stabilize it and keep it there under all conditions. That might not sound like a lot at first but it is when you think about it and the difference in actual performance and drivability is very impressive. Mark SC&C

at risk of sounding like a n00b, what affect does roll center have on handling characteristics of the car? what does it feel like? why would you want it to be lower?

[nowukno]

at risk of sounding like a n00b, what affect does roll center have on handling characteristics of the car? what does it feel like? why would you want it to be lower?

x2'

[Marcus SC&C]

PH, yep that`s the one.

We could spend pages and pages on roll centers,their locations on various cars and what effects it has under different conditions. In a Post It Note version a car leaning or rolling in a turn becomes an inverted pendulum. The roll center is the pivot point of that pendulum. The distance between the CG (center of gravity) and the RC (roll center) creates a moment arm. Think of it as a big lever prying the car over in the turns. The "hand" prying the bar is centriufugal force acting on the mass of the car. In the rear end of a G (or A) body the rear roll center is almost as high as the CG so the moment arm is very short. Lower the car and in this case the RC goes up and can reverse the moment arm entirely. Go over a bump and the RC moves up and down several inches,changing the length of the moment arm dramatically. As the car leans it also migrates laterally. These changes in the rear suspension (in addition to lateral axle movement,roll steer etc.) make the rear of the car behave,feel and respond differently with each change as they change constantly in every turn! Short answer it makes the rear end of the car behave erratically when you push it hard. A lot of clients have refered to it as squirm. There`s a LOT more to roll center locations and how watts links work than that,roll center height changes also alter spring rate,shock dampening rate and anti roll bar rate requirements etc. etc. but the basic goal here is to locate the rear axle as perfectly as humanly possible, locate the roll center in a slightly more favorable location and keep it and the rear moment arm length constant so the rear suspension behaves in a much more linear and predictable manner.
The end result is improved overall performance and a car that`s MUCH easier to drive fast. Basically if your ProTouring G body could take a "35mph turn" at 45mph without the watts you may be able to take it at 50mph with the watts and you`ll have the sense of control you did when you were only going 40mph. Does that make any sense? Mark SC&C

[nowukno]

PH, yep that`s the one.

We could spend pages and pages on roll centers,their locations on various cars and what effects it has under different conditions. In a Post It Note version a car leaning or rolling in a turn becomes an inverted pendulum. The roll center is the pivot point of that pendulum. The distance between the CG (center of gravity) and the RC (roll center) creates a moment arm. Think of it as a big lever prying the car over in the turns. The "hand" prying the bar is centriufugal force acting on the mass of the car. In the rear end of a G (or A) body the rear roll center is almost as high as the CG so the moment arm is very short. Lower the car and in this case the RC goes up and can reverse the moment arm entirely. Go over a bump and the RC moves up and down several inches,changing the length of the moment arm dramatically. As the car leans it also migrates laterally. These changes in the rear suspension (in addition to lateral axle movement,roll steer etc.) make the rear of the car behave,feel and respond differently with each change as they change constantly in every turn! Short answer it makes the rear end of the car behave erratically when you push it hard. A lot of clients have refered to it as squirm. There`s a LOT more to roll center locations and how watts links work than that,roll center height changes also alter spring rate,shock dampening rate and anti roll bar rate requirements etc. etc. but the basic goal here is to locate the rear axle as perfectly as humanly possible, locate the roll center in a slightly more favorable location and keep it and the rear moment arm length constant so the rear suspension behaves in a much more linear and predictable manner.
The end result is improved overall performance and a car that`s MUCH easier to drive fast. Basically if your ProTouring G body could take a "35mph turn" at 45mph without the watts you may be able to take it at 50mph with the watts and you`ll have the sense of control you did when you were only going 40mph. Does that make any sense? Mark SC&C
Got it mark....

[slimneverdies]

I sorta understand what you talking about. My friend has a 86 elco dropped 3" all around. Could you tell me exactly what it is to look for when driving, like when in turns, high speeds, etc... If I know what it should drive like then I will do as you suggest. He has had his like this for 3 years and probably doesnt realize the bad effect thats going on.

[The WidowMaker]

He has had his like this for 3 years and probably doesnt realize the bad effect thats going on.

thats one of the main issues i struggle with; ive only driven to the limit of my cars and never beyond, so i dont know what a good car would handle like compared to mine. so, when building the new car my initial plan was to build the car better than before, but mark has pushed me to build it to its best ability. why spend the money and do it good, when you can spend the same money and do it great?

the biggest problem with lowering a car is the geometry that results from that bitchin stance. lowering my chevelle ~3" put my roll center higher than the cog, gave me a huge understeer %, raised my AS to over 150% and gave me a really short IC. none of this is good for a track car, and its even worse for a street car.

moral of the story, do your homework, call mark and lastly, install a watts!!! it wont help everything, but it will lower your roll center and give you a better roll steer %.

[ScotI]

the biggest problem with lowering a car is the geometry that results from that bitchin stance. lowering my chevelle ~3" put my roll center higher than the cog, gave me a huge understeer %, raised my AS to over 150% and gave me a really short IC. none of this is good for a track car, and its even worse for a street car.
This would be my dilemma as well. I want the 'bitchin stance' while improving the handling.

The previous incarnation consisted of: Bell tech 2" spindles, Suspension Techniques 1.375" solid front bar, ST's 1" 'drop' 644# front springs, Monroe Formula GP shocks, & energy Suspension poly bushings. The rear was boxed GM arms w/poly & rubber bushings, Monroe Formula GP's, ST 1" rear bar & trimmed ST springs (not sure of rate). It was approx 3" or so drop. I loved the stance & it seemed to be an improvement over stock (not too difficult of a task).

My current round of parts now also includes SC&C's Stage 2+ front kit, Currie Trac rear arms, & Spohn relocation brackets. I've been considering the ATS spindle to get some of the 'drop' w/o the g-body spindle issues (dropped or stock) while allowing for some bigger brakes too.

The car is in the design stage (meaning it's disassembled :geek: ) so for re-assembly, I'm trying to select the right parts to meet the goal.

But I'm starting to think I won't improve things much simply because of the lower than normal ride height that's a requirement for my personal taste (air ride has been considered but I like 'em low all the time not just when parked). Is there any hope for my goals?

[slimneverdies]

Well fellas I hope Marcus chimes in with a comment to relive some of this obvious "toss of the coin" syndrome. I too have bought the belltech 2" drop spindles, OPG stockers for the front and 3" for the back.I already bought the upgraded c5 brakes to fit the spindle, also the UCA from speedway motors.
I have researched the @*it out of this and was under the impression that all I needed to get a better camber curve was to buy the large BJ's. I guess like you told me before Marcus, "just because people do things, doesnt mean that they should". Now after reading this its all in vain. I think mostly everyone here was after a bad ass lowered stance. Lastly, you say that the Watts link wont even help with that much drop.
I think Im losing my freakin mind:crying: :banghead: :screwy: Back to the drawing board

[nowukno]

Well. one thing I can say for sure is that with the front SC&C Stage 2+ kit, your front suspension geometry is still better than the factory suspension when lowered 3".

[ScotI]

Well. one thing I can say for sure is that with the front SC&C Stage 2+ kit, your front suspension geometry is still better than the factory suspension when lowered 3".
Kind of how I was thinking. But sooner or later, you reach the point of no return on investment. Like adding a Watts set-up to help w/stability on a car that's lowered 'too much' for it to be a benefit.

Ultimately, one would set-up the suspension for optimum manners/performance & then drop the body on the frame to set the ride height for the body. Sounds expensive though doesn't it :seizure: ....

[The WidowMaker]

the only thing you can do is start moving mounting points for the rear suspesion. i have about 20 hours in planning and design of some new brackets for the rear of my A body. they will drop the rear of the lca, raise the front of the uca, mount my coilovers and a phb. id run a watts, but its not going to be possible on my car since theres no room. the cad files are almost done and see what the end result is.

the watts will improve the roll center and roll steer, but it cant help with the AS and IC. the AS and IC require movement of the mounting pts. but, the AS and IC are huge during acceleration and braking, whereas the RC and RS and during cornering.

[nowukno]

My el camino is lowered 3" front and 2.5" rear with stage II kit and moded rear bar,(Waiting for Marks Rear bar) but the one I use does mount to the chassis and rear end ,not the rear arms and it feels fine to me on the street and on those long sweepiing on/off ramps.That stage II kit works wonders for G bodies.The Watts links has got to be a great add on, Mark,Im still trying to make my mind up on the Watts link.Butt like others I like my lowered stance too and Im just willing to deal with jacked up rear geometry,hey I only drive the car/truck about 500 miles a year if that and only in the summertime and in the winter only if its not raining or one of the cali 70 degree + days. Marcus and I went thru this many times and what I really like about marcus is that he's not out to just take your money,He gives the good and the bad of what your ride hieght will do and is truthful in his advise,that being said find out what your really going to use the car for and spend accordingly.Me my self, "rear geometry way off and loving it"
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[ScotI]

Yep, that's about the same stance as the Malibu & my old ElCamino had (the Camino was totaled so the parts were transferred to the Bu).


....the only thing you can do is start moving mounting points for the rear suspesion. i have about 20 hours in planning and design of some new brackets for the rear of my A body. they will drop the rear of the lca....
When I discussed my plans w/SC&C (mark) & told him the car was going to be lower than typical, he recommended & I purchased the re-locating brackets to drop the rear of the lower links to improve the geometry.

No plans for a track rat. The car won't see a track unless it's a 'spur of the moment' thing. Just a fun, decent handling car w/o breaking the bank..... I call it Joe-Touring.

[nowukno]

Yep, that's about the same stance as the Malibu & my old ElCamino had (the Camino was totaled so the parts were transferred to the Bu).

No plans for a track rat. The car won't see a track unless it's a 'spur of the moment' thing. Just a fun, decent handling car w/o breaking the back..... I call it Joe-Touring.Same boat here I know she's way to low But to me it handles great for what I use it for.But that watts linh is still callin my name Dang it Marcus!!!

[nowukno]

My wagon sits a little higher
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[slimneverdies]

Its offical! After nowukno's statement I think im gonna go ahead with the setup that I have. Lets face it, even if I went to the track, which Im not, None of us would drive these cars with all the work done to them every day. Man I love that stance nowuko. Only difference is that im going with the big wheels and rubberband tires. :cool:

[nowukno]

Its offical! After nowukno's statement I think im gonna go ahead with the setup that I have. Lets face it, even if I went to the track, which Im not, None of us would drive these cars with all the work done to them every day. Man I love that stance nowuko. Only difference is that im going with the big wheels and rubberband tires. :cool:I say build to suit you and what makes you comfortable since you have to drive the car..

[slimneverdies]

damn nowukno! you have adjustable suspension where u go from 3.5" up front and 3" out back to 3''up front and 2.5'' out back. Maybe thats a setup I should look into. So your still doing the watts link even though its not recommended with that much drop?

[nowukno]

damn nowukno! you have adjustable suspension where u go from 3.5" up front and 3" out back to 3''up front and 2.5'' out back. Maybe thats a setup I should look into. So your still doing the watts link even though its not recommended with that much drop?No,I wish Just estimating, I figure the stage II kit up front lowered it at least 3/4 of an inch up front with the 3" drop springs.Im still thinking about the watts for the lateral rigidity aspect.

[claytonisbob]

I don't understand. I thought the A & G body Fays Watts link was already available at SCandC.com/wattslink (http://scandc.com/wattslink.htm)

Is this there to let us know it's coming, or will be available soon?

Is there much difference between a watts link where the propeller is mounted on the back of the diff cover (welded mount on a 9", or bolted to a stiffer aluminum cover on a 12 bolt) vs. the fays2 style? To me it, the only differences would be in how you adjust it (outward vs. inward). And it seems like it would leave more room for exhaust.

Also, looking at the G-body Fays unit, it seems the links connecting the connecting rods to the axle tubes are pretty long. Does this allow any lateral movement? With the weight of the car in a corner pushing sideways on a sideways "L" it seems there would be at least a bit of deflection. Do those axle tube clamps hold tightly or has there been a case where they have slipped, which (especially) in a non triangulated 4 link (or 3 link), would be pretty awful.

[T-CHRGD]

I don't understand. I thought the A & G body Fays Watts link was already available at SCandC.com/wattslink (http://scandc.com/wattslink.htm)

Is this there to let us know it's coming, or will be available soon?

I have mine. Not installed yet (waiting for a few other parts) I will post pics of the install when done :twothumbs

[The WidowMaker]

I don't understand. I thought the A & G body Fays Watts link was already available

g body is done, a body is in the works


Is there much difference between a watts link where the propeller is mounted on the back of the diff cover (welded mount on a 9", or bolted to a stiffer aluminum cover on a 12 bolt) vs. the fays2 style?

the fays moves the propeller up and down with body movement. although this allows the RC to migrate, it more importantly keeps the RC to COG distance constant. this allows for a better feel throughout the corner.


Also, looking at the G-body Fays unit, it seems the links connecting the connecting rods to the axle tubes are pretty long. Does this allow any lateral movement? With the weight of the car in a corner pushing sideways on a sideways "L" it seems there would be at least a bit of deflection.

the amount of deflection, if any, would be negligible in my opinion.

Tim

[Marcus SC&C]

Hey guys. I dunno where to start so I`ll start with "drop". First of all I hate that term but it`s so common we have to use it. Companys can sell spring by drop but it`s never accurate. I`d be willign to bet that none of the 3" drop springs being sold are actually 3" drop from factory ride height. These cars don`t have 3" of factory bump travel. It would have every car running those springs sitting on the bumpstops with the pinion yoke almost hitting the floor. So you`re probably dealing with more like 2 actual inches. That still puts the RC way too high,messes up the instant center location etc. but as many of you know it`s still tolerable to drive. It`s not very well set up to begin with so it`s not a huge deal UNLESS you`re looking to get maximum performance out of tha car. For the G body guys we have runnign against C5s and Vipers in autocross and open course road racing details can be (and usually are) the difference between winning and loosing. They`re already at a disadvantage to cars like that so their setup better damn well be spot on. On a street car? Totally different. You can get away with a lot more because you`re not driving the car at 10/10ths ALL the time and probably not ever. I`m just being honest when I say that the watts isn`t the magic bullet to fix all the issues in a car that`s lowered more than is ideal. It`s true. It won`t fix running out of travel. It won`t fix the IC location or antisquat (although we carry LCA brackets to improve those). BUT it WILL still provide a huge overall improvement in performance and drivability! It may not be a magic bullet but it`s still a very effective bullet.
The links on the watts are the same size/type material commonly used in road race and NASCAR track bars (panhard bars) three times as long. Their short length vs. their size makes them very rigid. Likewise the axle clamps are NASCAR spec pieces. Usually one located the bar on one of those race cars. The watts has two the same size. I thought the same thing when I first saw them but after much testing I can tell you that they absolutely will not move (unless you loosen them to make an adjustment). Most chassis books you`ll find refer to the frame mounted watts as the superior of the two designs due to lower unsprung weight and an always constant moment arm length. In the case of the G body is also adds a much needed crossmember (they have to rear crossmember) for more frame rigidity as well. With the RC at the same height the links are in the same place with either style so clearance is pretty much the same. Frame mounted has less in the center,axle mounted has less on the outboard side. Mark SC&C

[nowukno]

"It`s true. It won`t fix running out of travel. It won`t fix the IC location or antisquat"
That's exactly what i mean about Marcus not being out to just get money from us G body guys he Speaks the truth and he wont tell you what you want to hear but rather what you need to hear.i appreciate that in a vender.Marcus is the the man .i will be giving you a call soon Marcus, Hey will that watts work with Spohn rear bar you have coming out in the future??

[Marcus SC&C]

Thanks man, I`m just doing my job the only way I know how.

Yes,they`ll work together. We designed them that way. :) Mark SC&C

[nowukno]

Thanks man, I`m just doing my job the only way I know how.

Yes,they`ll work together. We designed them that way. :) Mark SC&CMarcus,Im thinking of going the watts route,although my suspension is too low in the rear i can still benefit from the lateral movement aspect and chassis strength in the rear,correct?

[Marcus SC&C]

Absolutely! You`ll also gain a much more favorable rear roll center location that`s extremely stable compared to stock. :) Mark SC&C

[ScotI]

It looks like the Watts attaches to the frame rails w/bolts going through the frame. Is this the same for the G-bodies? What about if the frame was notched for tire clearance? My guess is there's going to be some fabrication required if the frame was notched.

[The WidowMaker]

if you have to do fab work, you might as well save yourself some money and get the weld in kit. mark sells them all.

tim

[Marcus SC&C]

Yep, what Tim said. :) All of the bolt in systems use a saddle bracket on each side with shouldered bolts to prevent crushing the rails. The weld in or Fab Fit version has an extra long crossmember. Just cut to fit,slide it up between the rails,line everything up and weld it in place. Mark SC&C

[GoldHawg]

For someone that has no rear end upgrades now, and wants to keep ride height close to stock, is this the best way to go? I don't see a sway bar in the pics, and perhaps you don't need as expensive a set of control arms with this? So maybe this isn't as expensive as it appears? Or do I still need all the good stuff? I had been planning on currie trac control arms and the new pro-touring sway bar that marcus promises this fall...

Thoughts?

[EagleEye]

man, i thought i new suspension.
you guys are giving me an education and a Headache. :banghead: :)


next.........

[Marcus SC&C]

Sorry about the headache, take a watts link and call me in the morning. :razz:

Lower control arms are still just as important. If the car isn`t lowered enough that you need to adj. the pinion angle you can easily get away with stock upper arms though when running the watts link. The watts takes a lot of stress off of them.

The adj. rear bar will be ready pretty soon. We`ve completed all of the testing and approved the design. Now it`s just a matter of the bars waiting their turn at the forge. :) Mark SC&C

[GRNOVA]

If you make a universal kit that is what I am looking for?
How much room does one need between the diff cover and the gas tank in my case? Her is my current set up?
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[XLexusTech]

Hey Mark I was told this is not nessaisary for a 4 link car. Is that true?
This pics above made me think to ask


New info. I plan on running a G link arom Art Morrison.

[The WidowMaker]

it is necessary for any car that runs a non converging 4 link and requires a centering device. if you have a stock c4l, then its not needed to control the axle migration, but still a good idea to lower the RRCH.

9.5" is more than plenty. i only have 2.5" right now, and im opening it up to about 4" to make it fit in my A body.

[GRNOVA]

Mark, you sure are doing your job! :yeah: Thank you for all the info and I will be waiting for my universal kit to arrive.

And yes, XLexusTech According to Mark the parallel four link is perfect for this set up! I will post pics after install!

[XLexusTech]

Mark, you sure are doing your job! :yeah: Thank you for all the info and I will be waiting for my universal kit to arrive.

And yes, XLexusTech According to Mark the parallel four link is perfect for this set up! I will post pics after install!

Yes Parallell for link I see. Andy you have a panhard bar so tht should locate just as well.

The G Link is a triangulated fourlink so I am not sure if a watts link is the way to Go. Maybe someone can set me straight.

I could awlays skip the G link and get a TVS and the Watts link that would save a bit of coin too.. But I would loose the adjustability the G link brings me

[Marcus SC&C]

The G Link (I assume you mean the Chassisworks G-Link) has much better geometry than the factory GM C4L rear suspensions so the watts isn`t needed. Parallel 4 links MUST have a lateral axle locator and most suspension texts and chassis engineers agree that a frame mounted watts is the best option if it fits within the space constraints of the cars structure.
GRNova, I`m anxious to see pics of your Deuce with the watts installed. It should be a very nice setup!
The factory GM C4L suspensions are poorly engineered from a performance standpoint. Not a suprise when you consider that they were designed first and foremost for low cost production and a big roomy back seat and trunk. They succeded in spades on those scores but it does a terrible job of laterally locating the axle (in the real world) and the roll center and it allows a huge amount of RC migration/change in the length of the rear CG/RC moment arm. It doesn`t look as bad on paper (computer) as it is because paper/computer assume the links are perfectly rigid and that the bushings have 0 deflection and 0 bind. Real life is a lot different. The bushings have to deflect quite a bit to prevent the geometry from binding even more than it does and they have to have NO deflection to locate the axle and RC well. You can`t have both. So we use the watts to redefine/locate the RC and to take over lateral axle location duty,both of which it excells at. Then the upper arms are only needed to control pinion angle. It`s a little unconventional on paper but on the road or track the improvement is immediately noticable and quite dramatic. :) Mark SC&C

[T-CHRGD]

I can't get pictures to upload, so let's try this link :
http://www.turbobuick.com/forums/2035389-post28.html
:)

[T-CHRGD]

Hey, that worked :)
here's another, with a few of my new Boze Pro Touring wheels :
http://www.turbobuick.com/forums/2036091-post124.html

[BigBlockOlds]

It looks like the Watts attaches to the frame rails w/bolts going through the frame. Is this the same for the G-bodies? What about if the frame was notched for tire clearance? My guess is there's going to be some fabrication required if the frame was notched.

Yes, so you just need to buy the fab fit version and fit it to your frame.
I was in the same boat with notched frame rails. Install was pretty easy. Made sure everything was level and plumb and welded the brackets together.

https://static1.pt-content.com/images/pt/2008/11/IMG_0976-1.jpg

[malibu43]

hi there guys,am JORGE from SANTIAGO CHILE,.
I have a 80 malibu and i do race as a road course open race,my big problems are how to get my car more handle,specially the rear.
this its my actual set up.
stock boxed rear arms, with poly bushings.
12 inches rear end with 4:11 gears ,non posi.
questions, do i need a panhard bar?,the bushings are ok for this kind of race?,my ride height in the rear is 4 inches,too low?,when i make heavy left hand turns the right wheel spin like crazy(how to solved?)
i will apreciated any help in this matter,please try to be a very basic language ,my english still its a very poor .
other question. what its the roll center? how to determinated?
thanks and my best regards from the farest country on earth.
JORGE

[83hurstguy]

I think your best improvements to start with are to put a posi unit in the rear end (limited slip differential), something like a Detroit Truetrac would probably work very well for your application.

I would also get rid of those stock boxed trailing arms with poly bushings. I would look at something like the Currectracs on www.scandc.com.

You wouldn't want to run a panhard bar with the stock converging 4 link rear suspension. As I understand it, you would be causing it to bind more... the panhard bar would want to swing a path which may counteract the path of the stock 4 link.

I'd recommend you pick up the book Herb Adam's "Chassis Engineering" to start for some suspension explanations. It's a very easy read. Another step up is Carroll Smith's "Tune to Win".

[wendell]

So don't use a parhard bar because of bind but buy a watts link?

[malibu43]

thanks guys for the reply,i got it.
but still i have lots of questions.
my ride height its 4 inches from ground to the frame(rear),I ve read that the car to low the roll center going too high, sorry but i don`t get it i dont know what its and how it works the roll center,can you help me?
regards

[JRouche]

thanks guys for the reply,i got it.
but still i have lots of questions.
my ride height its 4 inches from ground to the frame(rear),I ve read that the car to low the roll center going too high, sorry but i don`t get it i dont know what its and how it works the roll center,can you help me?
regards

Hi Jorge, welcome to the site.

Ok, Ill agree, get some decent books to help with the suspension. Thats what I did and I didnt know anything about suspensions, still dont :)

So, roll center?? Ill give it s stab, literally. Picture your car as a rectangular box. Now push a rod through the box lengthwise so the ends of the rod come out the front and the rear. Now hold the rod ends firmly and rotate the box on the rod. That is the roll center, where the rod is. Move the rod down closer to the bottom of the box and you have a lower roll center. Higher in the box then the roll center is raised.

Angle the rod so it is higher at the rear and lower at the front and that is how the roll center on alot of cars looks.

Now, how does a high or low rear roll center affect how the car handles? Picture the box again. If the rod is up high, put it up really high to exaggerate the condition. If the RC (the rod) is up very high the car will roll less because most of the mass of the car is below the roll center. Especially if it is above the center of gravity (not realistic though).

If the RC is very low then the body will roll more because now you can see most of the cars mass is above the RC.

Think in terms of circles for most of the suspension work. When you can get used to looking at all the movements as circular movements you will see it alot clearer.

Circles because everything is on a pivot, and as the various components go through their movements on the pivots they are describing a circle. Thats a very important concept to grasp to understand how suspension systems work.

And so now the roll center is also a pivot, not a physical one, but it is a pivot. So with a high roll center the car will pivot and most of the motion will be seen under the roll center. You wont see the motion because the tires will try to keep the car from moving. But the force is still there. And so I think, (not exact on this, off the top of my head) the force will try to push the rear end sideways, or more to the point rotate it, not push it. So for a left hand turn the top of the car rolls little, to the right (clockwise) and tries to rotate the rear end left (still clockwise). It wont push it though because centrifugal force overpowers the force and the rear end will still have to move right (in a left turn), but the rotational force is still acting on the rear end.

So the high roll center is trying to rotate the car and shove the rear end in the opposite direction of the centrifugal force. The CF is pushing is sideways, but the roll force is trying to rotate the rear end out and up. So your left tire will become unloaded..

Now thats a high Rear RC. A low rear RC (RRC) will cause the car to actually roll, you can see the forces at work now. The body rolls significantly more. And because there is less roll force on the rear end but the same amount of centrifugal force the rear end will slide out sooner. I think sometimes we see this as a problem of the roll of the body causing this, but I dont think so. The forces are all the same, Im talking about taking the turn at the same speed and all other conditions being equal. So the ammount of force hasnt changed. Just how it acts on the car.

Body roll is not a bad thing. It lets the suspension do its work, to a point. If you limit it too much then you better have a really light car with very large tires.

Ok, I only talked about a very small concern with roll center, and only at the rear. There are SO many other considerations to take into account. Front roll center, center of gravity, roll bars, suspension stiffness.... The list goes on and on.

A suspension system, READ system is a very funny animal, just like any other system. One sub-system interacts with the entire system and you may have to go back and re-look at the entire system after just one small change in a sub-system. Its all fun :)

Now.... Your spinning tire issue, the right tire on a left turn is puzzling, specially with an open diff. I would think just the opposite, the left tire should be spinning and you should be going slower. It doesnt make any sense. Unless you dont have an open diff??

Did I confuse you???? Im really sorry if I did. I tend to rattle on and write what comes to mind. I may be really off on some of my ideas though so just take what I say as my own ideas on how I see what the roll center does. Ok... Good to see a guy from abroad here!!!! JR

[malibu43]

thanks very,very much,i got it more clear now.
regards