Ibanez540r

In the process of finishing up my rolling chassis.. Although it came with OEM strut rods with new bushings, I realized one of them is bent. ..after thoroughly researching, I'm pretty sure I've decided on heim end rods. I'm building a resto-mod with a fair amount of power and fair amount of aftermarket suspension components. Bilstein sport shocks, VB&P rear dual mount spring, etc. so the heims seem to fit in well.

Lots of threads with lots of controversy on poly vs rubber, binding, noise, etc. and in most of those the guys that went with heims seemed very happy. So, on my search to purchase I was leaning towards the VB&P HD strut rods for $189.99

http://www.vbandp.com/C2-C3-Corvette...trut-Rods.html

They also have the Racing version for $249.99 which I assume just has better heim joints. Not sure if necessary or reliability of HD vs Race.

http://www.vbandp.com/C2-C3-Corvette...trut-Rods.html

I then found this post;
http://www.vettemod.com/forum/showthread.php?t=7776

..with all the part numbers to make your own Chromoly strut rods with AFCO quality parts. The only confusion here is on the spacers. Do the cone spacers quoted work to take up the space in the mounts or do you have to come up with something else to get them to work? This is an interesting option as you are likely getting equal or better parts to the VB&P Racing at $249 for less then the price of the HD.

Through more reading I started concerning about my use of 19x10 wheels with 285/40/19 tires and camber change with the OEM set-up. With the wider contact I'm wonder if I will see more irregular wear with the stock swing in camber which brought me to the VB&P smart struts at $290-$350.

http://www.vbandp.com/C2-C3-Corvette...d=smart+struts

http://www.vbandp.com/C2-C3-Corvette...d=smart+struts

THEN came across the Dragvette basic kit which consists of heim rods, and a spacer for the diff/strut rod mount which accomplishes similar results as the smarts struts. It also includes an 8in spring bolt but I already have one. This kit is the cheapest at $249.99. I'v heard nothing but good things about dragvette's stuff.

http://www.dragvette.com/products.htm


So... I guess I'm just looking for some persuasion .

TheSkunkWorks

For spirited driving on wide tires, I recommend quality heims with camber lock plates that eliminate the eccentrics (they simply don't hold adjustment under heavier cornering loads). If you decide to put together your own kit, but uncertain about just what you need, I'd call and have a tech spec out your bits for you.

You are correct to have concern about wide, modern, low aspect ratio tires not tolerating or requiring as much negative camber gain as did the, narrow, high aspect ratio bias ply tires which were the rule back in the day when the C2/C3 IRS was being designed. Not saying the engineers didn't know what they were doing (they most certainly did), just that they weren't working with the same variables, and tires are the biggest variable in the equation.

For drag racing (and only drag racing) you'll want to minimize negative camber gain in squat by either leveling the struts with the half shafts, or by installing a suspension layout with parallel, equal length upper and lower lateral links/arms. However, for anything other than dedicated strip duty IMCO you should lower your inner camber strut links to only ~1/2" below their stock [C3] height relative to the diff as the default baseline setting.

And, while not the direct focus of your rear camber concerns, don't overlook that static ride height determines from where on the camber gain curve, as well as the rear toe-steer curve (neither of which are linear) your dynamic alignment operates. I'll post more on this upon request, but hope that's helpful.


TSW

Ibanez540r

^ Thanks man. Two questions from that..

1. By "lock plates that eliminate eccentrics" I assume you mean NOT the smart struts which have the adjustable cam at the diff. connection? Rather the plates with the non-adjustable bolt?

2. Reference your recommendation to not lower the connection point more then 1/2", do you have any idea the lowering amount in both the smart strut kit, and the spacer in the Dragvette basic kit? (I think the dragvette spacer plate may be 3/8")

noonie

I used all the Speedway parts including the best moly heims they had.
They also have them in 3/4" thread, a little beefier.
I just welded up the stock inner mount and moved the holes down about 1/2"
The tube should be 13" instead of 12" as mentionerd in one of the links.
I made my own spacers on a lathe out of ss, but you can use the store bought ones.

You'll like the difference

Ibanez540r

Thanks on the 13" vs 12" info. Any chance you have a picture of the mount relocate? I have a welder and didn't consider fabbing the mount myself.

Still contemplating on which to get..

TheSkunkWorks

Yes, to your camber lock plate question.

The top of the inclination adjustment slot in VBP's SS bracket (available separately) puts the inner links ~1/2" lower than the stock height, which I don't consider a coincidence. That said, the fore and aft slots aren't lined up with each other (at least they weren't on mine), apparently to compenstate against the inherent angle of the struts as an attempt to minimize the loads placed thru, and potentially resultant binding of poly bushings. Also, unless they've addressed the issue, the bracket to diff mounting bolt holes are significantly oversized (as seen below w/bushing), which might well allow the bracket to shift under high loads, throwing off alignment.

All Dragvette kits seem to place the links in parallel, but not at equal lengths. So, while they greatly reduce camber gain they don't completely eliminate it. ...which seems a bit odd IMCO for a product obviously designed specifically for drag racing. The basic kit appears to be nothing more than a set of long spring bolts and heim-jointed struts with a bracket mounting spacer that levels them with the half-shafts.

noonie

The original holes were welded shut and I welded some 1/8" or 3/16" flat plate to go inside the original cam tabs, then drilled new holes to fit the heims lower than original. Doesn't have to be perfect, probably 30° misalignment allowed in the heims, unlike the oem rubber or poly setup.



Here is a pic of the seals I used over the heims. The heim, spacer and seals were a very snug fit before tightening the mount bolt.



Here is a pic of the parts from Speedway



Here is a nut welded to the strut rod so the jam nut could be tightened well.

Ibanez540r

^ SO the swedged steel tube didn't come with a wrench flat?

Solid LT1

nice job!

noonie

No, didn't think about it much when I ordered these, but they have them available, also in hex tubing.

Thanks

TCracingCA

I like the Tom's Differential strut bracket, because of the built in drop, similar to the old Herb Adams unit that I have on one car and similar to the unit that was sold by Global West. Or you can just add a block spacer under the stock unit.
For the strut rods, I like the Coleman Hex units because you can put a wrench on them anywhere and I use Auroras. The cone spacers I use to give the heim full ability to have room to rotate, not that that really comes into play for this application and it ensures that they aren't just lock in with washer or just flopping around. I also double nut everything.

PS I also put in the heim seals to keep the road grime out of the heim units. It is not easy to put those in and the cones. I like precision and getting everything tight is difficult whereas most guys just snug down the bolts and compress the bracket essentially.

Rally68

I agree, build your own heim-joint rods. The components I used (basically the same as noonie's picture) are rated for many more pounds than your tires have grip and the handling is much better than the stock rods with rubber bushings.

For spacers, I used pieces of DOM tubing with the correct ID (1/2" inner and 5/8" outer) along with some cone spacers from the catalog.

Nothing fancy, I cut the spacers with a chop saw and ground them till they were a snug fit. I used pieces of 2" wide 1/8" flat bar (you can buy at any home center--again, cut with my chop saw and a 1/2" hole drilled dead center) to make plates to eliminate the cam adjusters. I beveled the edges of the plates for a perfect fit in the brackets, so didn't see a need to weld them in. Spray Gray on the spacers and Chassis Black on the plates.




The stock cam bolts are 1/2"; the dragvette article references only 5/8 ID heims. Noonie's picture also looks like he may have enlarged the inner mounts to use a 5/8" bolt; I used a 1/2" grade 8 bolt. I was unable to find a 3/4" shank heim with a 1/2" ID, so if you want to use 3/4" shanks you'll probably have to use a 5/8" bolt on the inner side which I'm pretty sure means enlarging the adjustment slot, or part of it anyway.

It's a fun project, with very satisfying results. Good luck!

noonie

Yes, I changed the inner to 5/8" so everything would be the same.
Originally with the last set I made, I wanted to go 3/4" heims, but they were out of stock on some parts so I just went with the 5/8", still more than enough.