This is a very common thread among the many bulletin boards. I have been doing much research lately and came across a thread that contained a study that very much relates to this very question. here is the end all to the infamous question of which bushings are best for converging link applications (that's all "A" and "G" bodies in case you were wondering).

Link to thread I started on another forum (http://www.chevelles.com/forum/ultimatebb.php/topic/7/9117.html)

I see you found the Mustang bits and Maximum Motorsports :cool:

They seem to make good stuff and know their stuff.

I had missed the PHB details when I read that awhile back... didn't they also have data for their LCAs, a PHB, and a torque arm (no upper UCAs)? That is the combination they advocate.

I'd really like to see some independent testing and test results. No offence intended towards the company's research but they are selling a product and negative results don't sell product. I am also not saying they are wrong or right just that I'd like to see some independent testing and with and without the full complement of rear suspension. This is not complete and doesn't really tell the whole story albeit, the addition of the rear sway bar could add more bind or could improve the situation.

The people I know that have Mustangs suffer (new ones) from wheel hop really bad. They pretty much always have but the new ones are worse from what I understand. I don't own one so I can't attest to this fact I can only repeat what has been told to me. But then... Mustangs are not A/G body Chevrolets and they are certainly not a truck so while the research is good general knowledge its not application specific and should be looked at that way.

So testing a Mustang for things to install on the El Camino, of a much earlier design just doesn't seem good enough for me.

It is just my way of looking at things. Someone here, I think its Old Coot is doing something different and his is an El Camino and says its the best. So...

Id like to see SC. CHP or someone like that conduct their own tests and studies independent of pushing one specific product on you. Everyone says their set ups are the best. So not everyone is correct and I am sure that they all did some type of research on the subject and have number to back them up.

General Motors designed this and installed it onto the cars and trucks, well the El Camino truck most others use leaf springs. I would assume they did enough to get what they thought at the time was a good suspension system with some advantages over the older type suspension. They built a system that would be a good all around setup and last a good amount of time while giving a moderately fair ride and decent handling. They didn't design it for racing or concourse. So we know already it is inadequate for serious High Performance.

I would think that if we really wanted to get deep into it we should look at the way the Corvette suspension is made and its trinkets. That is about as close to full blown racing car as we would need but then we'd only be talking about Concourse Racing and not drag racing in the case of the Corvette @ show room status.

I don't believe that there is a best of both worlds! You have to choose which your going to drive constantly and put up with the weird stuff when you venture outside of the limits of your setup. Some of this stuff could be as big of a mistake to install as say, installing an Edelbrock Victor and an 800 CFM Carb on a Stock 305 SBC. Sure it works but not well and not at its zenith of operation.

My daddy told me don't believe everything you read it might not apply to you.

We're back to who's story is correct for the application "I" need? My way of seeing it anyway.

Pete, FWI the test results showed that their system had 3X the amount of bind as that of the #1 test. This test is recognized by some of the best engineers in the country and in the 3 years since it has been done has not been refuted 1 time.

The addition of the sta-bar will obviously deteriorate the results further, it is mechanically impossible that adding a sta-bar could improve the bind results.

The Mustang shares the exact same suspension design and it's pitfalls.

As I stated on the "other" site...suspension design does not care what your desired intent is within limits. If you put an autrocious design like a ladder bar on, it won't do anything well. If you put a half ass 3-link in, it can be tuned to do everything well.

If you want to discuss other options, we can do that. A 3-link/Watts link set-up IS the best stick axle design anywhere-period.

This thread was started to let guys running out to buy poly arms what they are getting into.

Steve, you are correct. I edited out the TA stuff as it doesn't apply to the "A" or "G" bodies. If you want it I'll email the entire text to you.

Hey Dennis, those are some interesting numbers and I don't want to get too far off topic, but I've been getting into suspension design lately and am even taking a class on racecar engineering at my school.

I've been tossing around the idea of doing a decoupled torque arm setup. Seems you would be able to get good antisquat numbers to improve acceleration and by decoupling the torque arm eliminate wheel hop on braking. You seem to be up to par on suspension stuff and I'm fairly new to it, so do you know any other advantages or disadvantages. I've heard they can be pretty hard to tune but other than that and fabrication time, is their anything else?

BTW I would order a new 12 bolt F-body housing from moser and have them fit it to a G-body platform to take care of the torque arm/housing mounting problem.

WOW 8O

Where can I find LCA's with spherical bearings on at least one end or are these something I have to fab up myself? I did not quite understand how durable the spherical bearings are so will they last for a few years or a few months in daily driving conditions being exposed to road grime and the like?

Justin, fab skill yes, tuning is no problem. Just takes time.

The decoupled torque is a great idea, most just aren't willing to deal with the wear out factor on the 3rd link for a daily driver.

82SS, you can pick arms from UMI in a couple weeks or fab your own with some PHB material. I may have a group deal on the UMI arms, hang out for a couple weeks.

I might be interested in those UMI arms too. Is there any rubber covering the rod ends for smoothness of ride, or is it just metal? There are a few people on ebay selling rod end (both side) lower control arms for around $80. One of them is ICEMAN on here I think. Will these UMI arms have mounts for a sway bar (even as an option) or should I just not have one? (I don't think my suspension can do without its sway bar :lol: ) And should I keep my Hotchkis adj. uppers or is there something better? I'd already have to sell my practically new Edelbrock LCAs for these rod end type! 8O

I beleive the UMI arms will have sta-bar provisions, I will check.

Better than the Hotchkis uppers....yep. Go back to stock arms with rubber bushings.

I've never seen spherical bearings with rubber bushings, I'm pretty sure there is no such thing. As far as NVH goes the LCA have no for/aft control so it shouldn't be much harsher than running low-pro tires.

That pretty much answers that. I knew you would say go back to stock :?

Is it worth it to get rod end UCAs?? I've seen them too. The rubber thing I was talking about is kind of like the Currie Johnny Joint with that rubber boot around it. Same basic idea right?

Here's the thing I never got about these rod end type control arms... how can they keep the rear in the center of the car around a turn if they articulate everywhere? Why wouldn't the whole rear move to the right or left around a turn? Would I have to have a sway bar or what? Would all the force around a turn be on the UCAs because they don't articulate? (Unless they have rod ends on the arms and in the rear housing. Can you put a rod end type bushing in the housing?)

I know a lot of what I think is a handling improvement is probably suspension bind not letting the car move as much from the poly bushings, but will the car be as flat around turns with the rod end type that let the suspension move more freely?

I'd love to have a more freely moving suspension, but these are just some things that don't make sense to me. Is there something I forgot about that keeps the rear centered? Is it because the UCAs are at an angle? I've been thinking about this since I heard of these kinds of control arms :huh:

Yes, the fact that rear arms are angled (converging) is ehat keeps the axle centered under the frame.

Using spherical bearings will have no impact on the axle staying centered (actually it would improve in the uppers but has been shown to be detrimental to smooth articulation).

Leave the upper axle mount as OE rubber bushings, these will aid in smooth pivot.

Yes, what you perceive as roll stiffness is simply suspension bind. Get the car to roll smoothly then adjust spring rate 1st then sta-bar size to increase roll stiffness.

The biggest problem with with binding suspension is snap-oversteer. This a condition where the suspension is tight as you start to roll then it violently upsets and breaks loose sending you into a uncoverable oversteer condition. There is no warning or indication of preoblem prior to the actual event, scary.

Remember smooth is fast, nothing should ever be a sudden or tight action.

This is what you could call a potpourri reply...

No Dennis I don't need the TA stuff since I am already quite familiar with that particular web site... I have a few of their parts installed on my daily driver already. There are a lot of vendors pushing Mustang pieces and only two seem to be universally considered "quality" rather than "hype". MM is one of those and Griggs Racing the other.

The reason I made the comment is because I have considered adding just a PHB to my rear and this suggests that I might want to reconsider that idea unless I also fabricate up a torque arm to go with it :-)

As to locating the axle with spherical links... the lateral location of the axle happens through the triangles formed by the four link suspension setup. Especially the UCAs. And the bind happens because none of the links travel in a pure single plane arc, there is always some sideways deflection.

If you want to corner flat, you can just manipulate the CG and RC (Roll Center) locations. With a SLA (Short/Long Arm) setup like on the front end you could even make a car lean *into* the turns. No springs or sway bars needed ;-) Of course it will not truly go around turns any faster that way but it can/could be done. The actual reason to control body roll is really to control suspension geometry of the front end. Years ago Lotus was goofing around with active suspension and found that the driver actually uses body lean to understand what the car is doing. It became harder to drive at the limit without the input cues of body lean to guage those limits by. But we all tend to feel better about less body lean anyways.

It really is short sighted to ignore good fully applicable information just because it is blue rather than orange. The Mustang uses the exact same design rear suspension as most (all?) El Caminos and so they do share the same problems and tradeoffs. There are a lot more Mustangs on the road than Elkys so there is a lot more investment in understanding and improving them. Why not take advantage of this since you are not going to find anybody duplicating this R&D for/with an Elky?

BTW the El Camino might have a slight edge over the Mustang in that the UCAs are longer and better able to handle loads. But the attraction of the four link setup is that it is cheap to build and adequate for the general masses who only want to roll down the road. But note that as expectations have increased the four link has been phased out for better designs. You would probably have a hard time finding a four link in current production.

Steve, I have since spoken to a few guys who have run the MM recommended stock uppers and bearings in the lowers, they went ahead and added the PHB against advice and were happy with the results at the OT events. One of them broke the PHB during an autoX event but it was a substandard part to begin with (makes you question how much of the lateral load the stock arms are "missing"). I am going to try it along with a PM3L as I need to get the PHB fabbed up before I can mess with the 3-link anyways. I'll post results of actual track experience.

As I think about it now I suppose it is not too surprising that a PHB with stock four link would have more bind as well as breaking a PHB. If you consider that the PHB establishes a new RC, there is going to be some amount of leverage from old RC to new RC as the body rolls. The lower you put the PHB and new RC the greater this affect.

Putting it another way, as the body rolls the old RC is going to be forced to move in an arc around the new RC. The amount of movement will be proportional to body roll and greater for larger arc radius (lower new RC).

I had always believed that the leverage and rubber mountings of the UCAs would allow more movement normally than would be required by the new RC. It takes rubber deflection to accomplish this which leads directly to bind as well as increasing the lateral load on the PHB due to the old RC trying to make the new RC move in an arc too.

It should be interesting to hear what your results are.

Hey Dennis, any news on the UMI arms??

I talked to Ryan early last week, launch has been post-poned a few weeks due to a design change and going with QA1 rod ends. They will be tube instead of boxed now. They should be available this month sometime.

I will post a pricing/ordering schedule as soon as Ryan gets it to me. Plan on less than 200/pair for the arms. Very good price for QA1 ends on adjustable links.

For the lower pair, right? I've seen the uppers on their site for about $190. I like them, but I hope we can get a pretty good price.

Yes, for lowers.

Will these have a sway bar provision?