Jasonty

There was a thread posted long ago about a 6 link setup that somebody was selling up in BC, canada. Did anybody ever come to the conclusion as to whether or not this setup would work on an 80-82? If not, what modifications are required? And if that isn't possible, does anybody know where I can grap a 6 link IRS setup for an 80-82? Thanks in advance folks...
-Jason :chevy

BSeery

I wanna know also -- TTT

Stingy74

The guy that makes them in B.C. (Rick Taylor) only makes then for the 63-79 Corvette suspensions. I wouldn't be afraid to try and adapt one to a newer car though. The bracket that cradles over the top of the differential in made of aluminum and so is the 80-82 differential and cover. If your good at making measurments and can deal with pulling the diff down, and then back up, and then back down, and up again you could probably get someone to modify/weld the bracket onto your diff. It would be highly worth it though.

This is a picture I posted awhile back. That big yellow thing in the middle is the bracket that would need adapting or welding to make the system fit an 80-82 type suspension.

Aaron.

terryrudy

Stingy, you got contact info and price or website for this guy? I need it for my "spreadsheet" of todo items. :)
thanks
-terry

ZD75blue

looks good stingy

Stingy74

Terry, check you hotmail account.:)

Stingy74

Thanks ZD. In case your wondering, that's Midas's 3" aluminized piping. I don't think i'll use it again. Seems to discolor and get brown and rusty looking but it infact isn't corroded at all.

Jester69Stingray

Can someone send me this as well i am interested in this setup for my car.

Thanks

Captain Morgan

Stingy,
Do you have any pics of the completed setup, whether on your vette or a different one? How about a website for the builder?

MIKER

The whole thing looks simple enough. I would even be willing to entertain the possibility of building a "do-it-yourselfer" setup for my '80.
The only part that really worries me is the fact that there might be some suspension geometry issues that would require some wicked trigonometrycalculusrocketscience type mathmatical calculations that are WAY over my head. I would enjoy the fabrication part of it and I have most of the necessary tools to do it.
Some of the forum members that currently have their bodies off the frame would have great access to the whole mess for measuring and fabricating.

Is there anyone on the forum with enough knowledge of suspensions that could provide guidance for such a project?
Is it absolutely absurd for me to even consider this as being a potential "do-it-yourselfer" conversion from scratch?

Stingy74

There isn't a site, as they are built by a guy in his garage. Allthough he's not the original designer, his work is second to none. Here's a few pictures, not the greatest but it shows my installed setup.

Stingy74

Well, no. But you have to completely understand how the 63-79 Corvette IRS works first. I see lot's of cool things i'd like to have have not having a clue how they work, how much they cost, or what they do but I want them because they're cool. This isn't really just something you put on. There's lots of critical adjustments to make and you'll need an alignment machine to do them. You also have to take into account that the diff will be down and you'll have to pop the cover off to remove the c-clips and possibly shorten the stub shafts. Nine times out of 10 you end up rebuilding the differential because everything is so messed up in there. It took me a long time to realize how things worked under there. I studied magazines, looked at pictures, talked to people on the phone...you won't truely appreciate the setup until you figure out the faults of the factory setup for yourself. Only then will you understand how the 6 link works.

MIKER

Your right, I don’t completely understand how the IRS works but I’m aware of the limitations of the factory setup.
I am at the tail end of a gear swap / rebuild of the DANA 44 from my ’80. That job has provided me with some additional insight on how the differential / inner yoke shafts interact. I understand that the drive axles are currently serving as suspension links. This contributes to excessive lateral movement and poor control over camber change throughout suspension travel.
After adding a top link to the suspension, the drive axle is no longer required to be a member of the suspension and therefore no longer requires the snap ring on the inner yoke shaft. The driven half shaft will now have to be telescopic so that it can follow suspension travel without interfering with it. Therefore the inner yoke shaft may need to have its length modified depending on the distance between the inner yoke shaft and the differential center shaft during maximum compression of the driven half shaft which will occur when it is linear with the differential. Fortunately, there is more than adequate length on the splined end of the existing inner yoke shafts to facilitate this modification. With that being said, we will assume that the differential and driven half shafts are out of the picture for now.
The part that I would need help understanding is the geometry required for proper suspension travel with regards to strut rod length and mounting locations (top and bottom, inner and outer). Getting this right would be critical to reducing suspension geometry variation. You also have to consider the load capabilities of the new upper strut rod mounting points. You could never accurately know what the maximum (worst-case scenario) pressure to these new mounting points could be and whether or not the existing material could support it. After all, additional stress at these points was not initially considered in the design.
Trying to learn how to make the upper and lower strut rods to work properly with each other could definitely keep me sleeping at night!
I suppose that you also have to give consideration to “benefit vs. effort”. It would be difficult to quantify the actual results. The “WOW that’s COOL lookin’” factor would be off the scale but would the end result actually yield an improvement that was worth the effort? I don’t know enough about it to take a shot at that question yet but I can darn sure say that it looks like a neat setup on your car.
I’m now convinced that this stuff is WAY over my head for now so I guess I’ll have to settle for the easy route by simply doing the best that I can with the current setup. Doing things like installing new adjustable strut rods, lowering the strut rod mounting points (if exhaust clearance allows!), minimizing the end play associated with the inner yoke shafts and wheel bearings will probably help my car a lot.

This is the best part about being a Corvette Forum member, tossing around ideas and sharing information about this one thing we all have in common. :D
:seeya

flynhi

Miker,
I'm about to replace/rebuild my rear end and have been considering the upper strut rod kit from the canadian. But I don't want to open up a whole new set of problems.
I thought the purpose of the upper strut rods was to unload the half shafts and prevent them from moving in and out due to load and wear. If this is true, I don't understand why different yoke shaft lengths would be required.
If the OE shaft lengths work in various wheel locations (up,down,centered) when loaded, why won't they work when the wheel is in the same locations and unloaded?

I agree with your comment about needing an alignment machine to get this set up properly (and I suspect that finding an alignment guy who can do this will not be easy), but it seems to me that the upper strut rods will position the side yokes at one location and the camber change/end wear issues will be solved.

Your comments would be welcomed.
Will.

Stingy74

Exactly, I guess i've underestimated you.

Actually, the stub shafts don't have any lateral movement anymore so lenght isn't critical in that aspect but there is issues with regards to setting your toe which requires identical amount of adjustment on the new upper rods as well the lower rods. After camber is initally set the kit requires you to turn the rods at the same rate, in or out, as to not change the camber you just set. If your toe has to come in there is a possibility the butt ends of the yokes may make contact with the shaft in the differential. That's where the shortening comes in. Mine are stock length.

I don't think there is any physical changes in the distance between the upper rods attachment point at the diff and at the trailing arm for an 80-82 as opposed to a 63-79, so I think you could get away with leaving the upper arms at their current length. What you would have to be sure of is that the differential cradle bracket would have to sit in a position that would be identical to how the 63-79 would sit to keep everything within their working ranges. That's the only thing i'd worry about because everything has to be parallel to each other to work and if mounting points were off one of the components in the system would be holding back the other two from doing their complete assignment. As you mentioned, this could create additional stress on the pivot points and would defeat the purpose of the system.

Initally no because you'll have just finished the ugly process of installing and it and going through alot of trial and error setting. After the hatred has worn off you can appreciate the fact the camber change is nill and you'll always have a full contact patch on the tire which get's noticed in drag race situations or autocross/slaloms events, which is what the kit was actually designed for.

I can't remember if I mentioned it but the kit comes with the hardware to lower your lower strut rods so that they are parallel to the upper rods and the half shafts. Everything is parallel to everything else which has the suspension act as if the 6 link wasn't even there. It all moves as an entire assembly. You still have full suspension travel, just without the camber change. This is absolutley no loss in driveability and I have yet to find the limitations of the setup.

Stingy74

I mentioned in a thread above why the stub shaft lengths might need to be changed. It has to do with toe, not camber. Also, most of the time the stub shafts are so beat up the you are required to cut the mushroomed end of if you want to re-use them.

Yes, that exactly what the kit does. It holds the trailing arms in place. With the trailing arms in place, the rotating half shaft it's attached to won't be able to move either effectively ending camber change.

inqbus383

Could I get the webpage/contact info for this? Thanks in advance :)

aro@u.washington.edu


[Modified by inqbus383, 6:52 PM 12/4/2001]

DaveL82

I fail to see how this has any effect on correcting toe issues with the 63 to 82 rear designs. This does allow you to take the upper link off the axle shaft and you can move the spnidle assembly in and out with respect to the single mounting point of the trailing arm which will change toe in or out, but once set, the toe change over the up and down movement of the wheel is still there.

You still have rear toe steer. Example: remove the spring from one of the control arms so that the axle pivots easy. Do this on an alignment rack and even with the new upper link the toe will change as the axle moves up a down. This is because the spindle moves in and out as the wheel moves up and down in relation to the fixed front mount for the trailing arm

This is why 84 and up and Gulstrand (spelling?) make the front mount for the control arm pivot (two links). The control arm is replaced by two links that are there only to locate the spindle front to back. These two suspensions then have adjustable links that go from the rear of the spindle (about 3 to 4 incjes back of the axle centerline) to the housing. This link is made to be the same length as the lower and upper links so that it eliminates the toe effect as the axle moves up and down. The toe is then adjusted by lenghtening or shortening this rear link.

Hope this makes sense

Stingy74

Some guys have suspensions that are out of whack...bent parts, stuff out of spec..I had a right rear trailing arm on my car that was sandblasted and painted. Looked real good, until I got it on an alignment machine. To make a long story short the arm had come from a 75 that was in a wreck and consequently got bent inward. While aligning the rear I had problems acheiving the zero toe I wanted because the yoke would butt up in the diff and stop. An easy fix would have been to shorten the stub but I instead got another trailing arm and installed it with all the shims on the inside of the frame. This gave me lot's of room for adjustment as I was able to turn both rods like required and acheive 0. There's alot of variables within the rear suspension and the yokes are one of them. Liek I said earlier, my yokes are stock length but some guys prefer to shorten them for that reason and because most are wrecked anyway and have to get cut off after the damage point. It simply an install procedure and has nothing to do woth toe change issues.

DaveL82

OK, so from the info, looks like the new upper link only addresses the camber issue. Both upper and lower links can be adujusted to change toe, but this does not correct the toe change problem as the wheel arcs as it moves up and down.

As an FYI - toe change is the most critical fault with the C2 and C3 suspensions.