Control Arm Bushings... what do we need?

[davytudope]

if you do get the ES kit and receive the wrong sleeves you can do like i did and get a machine shop to grind down the sleeves. it didnt take them much time and it was cheep. and the sleeves looked real good, not hacked up. also it proved to be a lot better than dealing with ES. i had a very bad experience dealing with ES.

[mkriebs]

Wow... those are alot different from the spherical ones. Ours don't have sleeves, and it looks like a completely different setup up front .And that sucks that SCCA doesn't allow them...

[DrJones]

Originally Posted by mkriebs Wow... those are alot different from the spherical ones. Ours don't have sleeves, and it looks like a completely different setup up front .And that sucks that SCCA doesn't allow them...

They allow them, but only in the Street Mod, Prepared and Modified classes. They are fairly equipment and $$$ intensive classes compared to Stock/Touring/Street Prepared.

[mkriebs]

Hmm, I might think again about putting mine in then...

[rlhammon]

I know that PFADT makes a slick setup.. and yes, they aren't willing to devote time currently to the Kappa platform.

I have been talking to a different company about making some bushings for us though. They are currently thinking it over, and I should hopefully hear back from them in a week or so (or I'll call them at that point).

Without going into much, since I don't want to get anyone excited for something that might not work.. but Alex mentioned Delrin... that's what these guys do. They are interested in the project, but skeptical about the volume. If I can get them some dimensions... then they can look at the parts they currently make and maybe development time will be lowered to the point that the project makes sense.

If need be, I'll just get a set of the ES poly's and send them to this company. See if they want to do it... and get something made. If not, then get the set back from them and call it a day with ES bushings.

[Krazed Kanary]

Talking with the GM engineers I was told several times that the control arms on the Kappas were originally used on Corvettes (year/model???).
I would never use all metal bushings spherical or otherwise or any other non resilient material like delrin, teflon, nylon etc for that matter, on a street driven car. If it didn't jar your eye teeth out, they would beat themselves to death in no time at all.

[snaponbob]

If they were, they SURE weren't on C6's or C4's, and the the C5's don't look right either. The lower shock mounts are completely different as well.

[rlhammon]

Small Dealer has previous indicated that our Control Arms are unique to the Kappa platform, as a part number search turned up nothing. I was hoping to find a hit on another vehicle to help with development for the bushings.. but no such luck.

[SolNut]

Rumor I picked up was Caddie CTS. (and a long time ago)

Perhaps their Dash V's have a option for us?

Steve

[snaponbob]

I had Googled C5, C6, and C4 control arms, and they certainly are not Kappa control arms. Today I had th e wheels off, and I can clearly state that these are NOT Corvette suspension pieces. I can look at Caddie stuff as well, but they will not be the same either. The engineer was wrong.

[SolNut]

Originally Posted by snaponbob I had Googled C5, C6, and C4 control arms, and they certainly are not Kappa control arms. Today I had th e wheels off, and I can clearly state that these are NOT Corvette suspension pieces. I can look at Caddie stuff as well, but they will not be the same either. The engineer was wrong.

Sorry Bob, it was the rumor I heard.

Steve

[snaponbob]

Originally Posted by SolNut Sorry Bob, it was the rumor I heard. Steve

Rumors happen. Here's one that is NOT a rumor - Corvette sway bar links are PLASTIC. Weird.

Unrelated - I saw pictures of Alex Jones black ES bushings all scrunched up so I jumped under my car and took a good look at mine. *sigh* No such issues he !!! Guess I need to brake harder, huh?

[Krazed Kanary]

Originally Posted by snaponbob I had Googled C5, C6, and C4 control arms, and they certainly are not Kappa control arms. Today I had th e wheels off, and I can clearly state that these are NOT Corvette suspension pieces. I can look at Caddie stuff as well, but they will not be the same either. The engineer was wrong.

Might want to PM Flash's owner and tell him that, I seem to recall he was the head engineer of the Kappa platform development at the time, so I tended to believe him.

[snaponbob]

Glad to. But SOMEBODY is wrong. I will be glad to post the links to the pictures. The very FIRST indicator that the control arms are different is that a) the C4 arms look NOTHING like Kappa arms, b) the C5 & 6 arms look similar to Kappa arms, but are not the same, because c) the lower shock mounts are completely different than Kappa shocks, thus the mount points are completely different on the arms, and d) Kappas use coil springs and Corvette use leaf springs. Look for yourself. Maybe Steve said the Kappa uses control arms "like" the Corvettes, and THAT would be correct. But "like" is not interchangeable, just similar.

Corvette C6 springs - Google Search

Art Morrison.com

Chevrolet Corvette control arm, great deals on eBay Motors on eBay!

C6 Parts : C5 and C4 Used Corvette Body Parts : Corvette Suspension : Front Bumper : Vette Parts : Corvette Repair and Salvage

[Flash's Owner]

Originally Posted by rlhammon As I said.. I'm trying to get something else made other than polyurethane. Every experience I've had with them they squeak like crazy. Seeing as I drive the car as a daily driver I won't be able to stand the squeak. That dang cold weather squeak on the front sway bar was bad enough... I couldn't handle the noise if every bushing in all four A arms was squeaking. Maybe they aren't squeaking... maybe they will be fine... but at this point I'm looking to get something else made, or machine up my own. I'm just trying not to buy a set of Energy Suspension bushings to get dimensions... that's all. I can't use the stock bushings as it looks like I have to tear them out, and they aren't a part I can order.

Originally Posted by snaponbob I installed my poly stuff in January. After 5000 miles not a sound from the control arms. The system is completely different than how the sway bar works. The bushings go in the control arms, sleeves go in the bushings, and bolts go in the sleeves. JUST LIKE THE OEM SET UP !!!!!! (Over simplistic, but that's how it is.) Basically, with poly control arm bushings, there is EXACTLY the same chance of noise as with the stock bushings. That said, they are all that is available, but they are TOO simple, and should be split instead of one piece bushing. The absolute slickest system I have ever seen is produced by Pfadt. Scroll down and see the assembly animation. New Corvette Control Arm Polyurethane Bushing Kit | Pfadt Race Engineering And, NO, they are not interested in doing anything for the Kappas. Already been WAY down that road with them.

We had one car setup with polyurethane bushings, I think they may have been Energy Suspension's setup. It lasted about 2000 miles before the traditional creaking and squawking came in. Once it starts, it keeps going and in cold can be very loud.

Improvements in steering and handling were noticeable but minimal, compared to the relatively high rates of the GXP bushings with the bulged inner metal. Minimal ride degradation, but again noticeable.

I would not recommend doing the differential bushing (for the non-Torque Beam cars). It sounds like a toolbox full of wrenches because the differential has no isolation. If your car did not have clunk before, it will after replacing the diff bushing. (statement not applicable to the turbo applications and the cars with a torque beam).

Originally Posted by rlhammon I'm wondering if we might just be better off getting a set of Energy Suspension poly's and using those for measurements. My hope was that maybe Alex had the dimensions still from his development work with them. I've looked on the install directions, but no dimensions are listed. If all goes well here shortly I'll be doing some coilovers and I can pull the A-arms off then.

This is probably your best bet.

Originally Posted by Krazed Kanary Talking with the GM engineers I was told several times that the control arms on the Kappas were originally used on Corvettes (year/model???). I would never use all metal bushings spherical or otherwise or any other non resilient material like delrin, teflon, nylon etc for that matter, on a street driven car. If it didn't jar your eye teeth out, they would beat themselves to death in no time at all.

Originally Posted by Krazed Kanary Might want to PM Flash's owner and tell him that, I seem to recall he was the head engineer of the Kappa platform development at the time, so I tended to believe him.

Sorry, perhaps you understood incorrectly. The suspension and control arms are 100% Kappa only.

Now, during the early development of the platform, before it was called "Kappa" even, we looked at "downsizing" scenarios, including a shrunken corvette where we use all of their control arms (too expensive, way too difficult to package, no way to make it coil over without redeveloping the LCA), also looked at other platforms for control arm parts scavenging, including potentially using things like Trailblazer coilovers, or Canyon suspension components, etc. While we did use some specific parts (like the shock diameter and internals and even the upper shock mounts, for example, are pretty much Trailblazer/Envoy parts), the rest of the suspension was developed from scratch.

In the end, the best decision was made - to develop a new platform with completely new control arms and suspension.

Bushing dimensions are in the ballpark of other uses, but they are enough different that they are not interchangeable with any other applications - except for a couple of exceptions:

-the large bushing (called the ride bushing) in the front is sized to take a 2008 and previous Cadillac CTS ride bushing, which is hydraulically damped and very low rate. This was just in case we needed to mitigate some issue specific to the then-unknown architecture, such as wheel imbalance sensitivity or the need to damp out a lateral shake issue. Luckily we did not need to do it, because the few times I tried one, it made the steering so mushy (but slightly improved the ride! Yay!) that it would have felt like trying to drive a truck.

-The rear suspension, lower control arm larger bushing (also the ride bushing) is sized to take another platform's smaller hydraulic bushing for the same reason. Again, luckily, we did not need to use it, because I only tried it once - made the rear so waggly and non-confidence inspiring, that it would have been completely unsatisfactory.

Most of the bushings require a small press and a properly sized arbor to press them out of the arms. Use liberal amounts of glass cleaner, and it is best to press them in with "bushing funnels". We made our own.