[Jsup]

I'm going to drop my rear shortly, and when I do, I am going to replace the rear suspension with a 10 link upgrade for the IRS.

1990 Corvette, going from a D36 to a D44. Typical IRS for these cars.

These 10 links require that I purchase Heim Joints, total 20.

The car should put 450-475 to the wheels when all is said and done.

I note that Heim Joints run from $3 each to $22 each. Other than being Teflon coated, what else are the differences between these joints. HO much do I need to spend to get ones that will do the job with some headroom? Do I NEED $22 joints or can I use $8 ones? Remember again. I NEED 20 OF THEM!

Thanks.

[ericnova72]

The cheaper versions have only a mild steel body and shank, while the more expensive have a chrome moly body and shank. Both will have hardened steel balls and races, but the chrome moly bodies have roughly twice the load rating. If you buy a 4-link or ladder bar kit, I can't think of a single company that equips them with mild steel hiem joints, they will only sell you the chrome moly.
I realize we are talking difference in actual loads in your case because it's IRS, but here is what I've done in the past: If the link in question has to transfer a power load, then it has to be chrome moly. If it is a lateral load like a Panhard Rod, Wishbone, or diagonal link I then consider it on a case-by-case basis as to whether mild steel will be ok for these pieces only.
Best prices I've been able to find are at www.jrmotorsports.com and they have a nice chart of load ratings on all the rod ends.
If in doubt, go stout; because if it breaks at any kind of speed you will probably total the car along with potential human injury.

[Jsup]

This site you listed has Aluminum ones too, what is your take on that?

[ericnova72]

Aluminum is only for Sprint cars, Midgets, and light Modifieds. They have the lowest rated capacity on their in-catalog chart. They're not for drag or street suspension use AT ALL, just small linkages like throttle, electrical shut off, or shifter. Even when used on a Sprinter suspenson they require frequent inspection and replacement, they are only for saving weight.
You might want to get their catalog, it is loaded with tech tips and charts on practically every page.

[Jsup]

Originally Posted by ericnova72

Aluminum is only for Sprint cars, Midgets, and light Modifieds. They have the lowest rated capacity on their in-catalog chart. They're not for drag or street suspension use AT ALL, just small linkages like throttle, electrical shut off, or shifter. Even when used on a Sprinter suspenson they require frequent inspection and replacement, they are only for saving weight.
You might want to get their catalog, it is loaded with tech tips and charts on practically every page.

I'll order one thanks. I need 20 and at $50 each, well do the math. It's steep.

Maybe I'll get 10 good ones, on the lateral and use cheaper ones on the parallel ones. Do I HAVE to spend $30-50 each or will any Chro-mo do?

There's two things at play, what I need, and what it cost.

[ericnova72]

I've been using the PRC Pro Series (3/4"x 3/4" in my case at about $15.00 each) in drag race 4-links, and wouldn't use anything less in your case if it was me, but ultimately you will have to look at what function is performed by each of your links and make your choice. You might be fine with mild steel in some locations, I'm only familiar with older vintage (Stingray) vette suspensions.

[Jsup]

BTW, I don't want to leave the impression that what I am giong to go CHEAP. I want to buy what I need to do it right, as cheaply as possible.

I'm not going to get lesser quality parts than I need. I'm going into my Factory Service Manual and try to put a picture up of the IRS to see what you think.

Thanks for the help.

[kruzr]

With that much power at the rears,I wouldnt hesitate on the best joint.
They are going to take one heck of a pounding unless the car is for show.

Buy extraaa$$$ cause you"ll prob be changing them sooner than anticipated and I wouldnt want to be stuck waiting for an order to come in from timbucto.

[mechEcwru]

Just do a basic force analysis on the rear end.(free body diagram) If you send me a picture or link of the proposed rear end, car weight, tire selection and the cars intended use I can give you my opinion on what joints to buy.

[Jsup]

Originally Posted by mechEcwru

Just do a basic force analysis on the rear end.(free body diagram) If you send me a picture or link of the proposed rear end, car weight, tire selection and the cars intended use I can give you my opinion on what joints to buy.

Thanks man, will do.

Here's some links as to how the rear works. The suspension kit I am getting replaces the four "dog bones", two on each side, as well as the lateral ones that run past the leaf spring in back.

I have a 1990, these may be different years, but essentially the same.

http://www.rodandcustommagazine.com/...ion/index.html

http://www.progressiveautomotive.com/sweetrear.htm

http://67-72chevytrucks.com/vboard/s...d.php?t=310353

[Jsup]

Originally Posted by kruzr

With that much power at the rears,I wouldnt hesitate on the best joint.
They are going to take one heck of a pounding unless the car is for show.

Buy extraaa$$$ cause you"ll prob be changing them sooner than anticipated and I wouldnt want to be stuck waiting for an order to come in from timbucto.

Well, the best joint for the job and the best joint are two different things.

For example, I saw a guy on one forum recommend $1200 rods for a 500 HP motor when $500 rods would do. You don't need $1200 Billet Callie Rods until you're into the 1200 HP range or better. So using the $500 rods would give you a 700HP margin of error, 140% which I would say is pretty safe. The same guy also told me that I'd need a new radiator, for $700 because my 427 would never run with my current one, well 183* all day long in 90* weather with the air on with my current radiator.

So that is what I'm trying to figure out, the best part FOR THE JOB without buying $60 Hiem Joints that are necessary in 2000HP applications, but not fo me. If $60 joints are necessary, I will buy them. However, let's determine if it is necessary first.

[johnsongrass1]

I would use Pro 1 series black. 3/4 shaft and 3/4 hole. Keep and eye on em for safety. Heims are gonna wear faster than normal but the the trade off you are looking for. Performance vs longitivity. $15 a piece I think.

[ericnova72]

I agree with Johnsongrass1, PRC pro series 3/4"x 3/4", bush down the ball hole if needed, don't need the teflon/kevlar race unless you want it. Only link I might use anything smaller is the toe-in/out adjuster link but no smaller than 5/8".
Also, chrome moly tubing for all.

You are looking at $700+ for rod ends, tubing thread inserts, and tubing; and thats just a guess, it could be more. An alternative might be to look into the possability of fitting a monoball (or polyurethane) into the ends of the dogbone links in place of the rubber bushings, and only making moly tube links for the lower birdcage to centersection. Any links that end up heavier than the originals is a step in the wrong direction in a race suspension (unsprung weight).

The monoball stuff is easiest to find if you look to the rock crawler and 4x4 crowd.

[Jsup]

Originally Posted by ericnova72

I agree with Johnsongrass1, PRC pro series 3/4"x 3/4", bush down the ball hole if needed, don't need the teflon/kevlar race unless you want it. Only link I might use anything smaller is the toe-in/out adjuster link but no smaller than 5/8".
Also, chrome moly tubing for all.

You are looking at $700+ for rod ends, tubing thread inserts, and tubing; and thats just a guess, it could be more. An alternative might be to look into the possability of fitting a monoball (or polyurethane) into the ends of the dogbone links in place of the rubber bushings, and only making moly tube links for the lower birdcage to centersection. Any links that end up heavier than the originals is a step in the wrong direction in a race suspension (unsprung weight).

The monoball stuff is easiest to find if you look to the rock crawler and 4x4 crowd.

Blowerworks.net they make a rear suspension kit for the Corvette. They make all the aluminum rods, which are blue and my car is blue. They are already made up all I need is the joints. He has 10 sets of New Old Stock. They used to sell for $2000 without the joints. He has them on sale for $900. Greg is local to me, so I can get them for $500. If you download his C4 catalog, page 73.

I'm picking up the owner's manual tomorrow to see what sizes I need. I think they are 5/8s not positive.

Anyone else with a C4, if you're interested let me know. I'll work with Greg.

[aosborn]

It looks like you have got good info for heim joints, but have you considered re-bushing the stock trailing arms with poly-graphite or polyurethane? The toe adjusters already have non-deflection ball ends, and you could re-bush the camber arms also. It would save you a ton of bucks! I have installed Herb Adams camber arms, they are strong, lower the roll center, and not to pricey if memory serves. The stock components are quite strong and light, just the rubber bushings are too compliant.

Andy