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Fri Nov 23, 2007 7:58 pm

How does one go about lightening the front suspension action for a glass buggy? I'm currently assembling an aluminum beam with used stock torsion leaves and stock trailing arms and I've got a set of pre-worn Cofap shocks. I imagine it involves removal or alteration of the spring pack, but as I have never done it I figured I'd ask those that have. I tried searching but have not found a clear cut answer.

Fri Nov 23, 2007 8:29 pm

It can be done by reducing the number of torsion leaves in the upper and lower tube.

CAUTION!!!!

Because the torsion bars are held in place by "grub screws", and the trailing arms are held on the same way, you must take some precautions. For what ever number of leaves you remove from each tube, you MUST replace that leaf with a series of spacers. These would be located in the center of the tube, and in each trailing arm effected by the removal.

Example:

Say you remove two of the skinny outer leaves (also known as bars, slats, leaves, torsions,etc...) from the upper bundle. Once done, the bundle will no longer lock in with the grub screws. Well, at least NOT SAFELY. So, you need to make spacers to fill these voids.

I normally take the old torsion bar/leaf/slat and cut short pieces off of it for spacers. I then place them in the necessary places at the ends and in the dead center and spot weld in place.

Reinstall the torsion bundle and give it a spin.

Fri Nov 23, 2007 8:50 pm

So, would removing inner sections of the thinner leaves and leaving the 3 grub screw locations intact be a safe way to accomplish this? The bulk of the grub screws holding power comes from the center, deepest portion of the indents, correct? Thanks LoCash John, I was hoping you would answer!

Sat Nov 24, 2007 9:50 am

I've had good sucess with removing the top and bottom full leaves, and replacing them with the half width leaves. So now we run 6 of the half width leaves instead of 2. Pleanty of motion on a F/G buggy, but still goes together like a stock beam, no welding or fabricating needed.

Sat Nov 24, 2007 2:38 pm

Thanks 5150, I've got a few extra set of leaves so I'll start tonight. :)

Sat Nov 24, 2007 3:42 pm

If you have adjusters, the best way, is to release the tension on one torsion tube to the point that the ride height is just about to drop. At that point, the bulk of the load will be on one set of torsions and the second set will work progressively, the further the suspension goes thru it's travel the tighter the suspension will get.

Sat Nov 24, 2007 4:32 pm

Jerry, I am working with an aluminum beam without adjusters. I am thinking about welding a set in however, just got a set a few days ago. The beam I got is just one of those $125 deals you see everywhere. I have 2 questions about it however... This beam has the shock towers roll pinned to the tubes and one is actually quite loose, that can't be good can it? As the spring pack locates in the center of the beam to support the load will the beam mounting clamps be sufficient to prevent tube rotation? Cuz' I know those two 1/8th roll pins won't cut it. Then I'm trying to figure out how much I can raise the front suspension before the action is compromised. The beam isn't drilled for the center grub screw location, so I figured now's the time to raise it a bit over stock. Are there any formulas or tips to determine how high I can set it? Thanks!

Sun Nov 25, 2007 5:13 pm

I have seen some backyard formulas to determine the ride height, but I don't know where it was.
I would wait until the buggy is completed so the weight will be on it. That way you can precisely set the ride height. Pull the roll pins and let the tube turn to set the ride height, then weld the tube to the shock tower, to keep the roll pin from failing.
I machined adjusters and welded them on my aluminum beam. Two months later Jamar came out with adjustable aluminum beams :roll: .

Mon Nov 26, 2007 4:58 am

5150bossman wrote: I've had good sucess with removing the top and bottom full leaves, and replacing them with the half width leaves. So now we run 6 of the half width leaves instead of 2. Pleanty of motion on a F/G buggy, but still goes together like a stock beam, no welding or fabricating needed.
what do you mean by half width leaves?

Mon Nov 26, 2007 11:23 am

The spring pack consists of mostly the wide leafs which are just over 3/4" wide. Then there is one 3/8" wide leaf on the top and one 3/8" leaf on the bottom of the pack. I replaced the first and last wide leaves with two of the narrow leaves. So there are six total of the narrow leaves in the beam now instead of two. The theory being that with more narrow leaves, the amount of torsional force needed to twist the pack is reduced due to less rigidity in the pack, yet everything still fits properly without having to fabricate any spacers (similar to removing two of the large leafs). You can probably pick up the narrow leaves from a junk yard or an old beam or two somewhere. Or you could order them from a place that builds beams.

Mon Nov 26, 2007 1:40 pm

When I had my beam narrowed, I also had this mod done to the spring bars:

http://www.mach4.com/manx/week10.htm

I haven't installed it yet, but it should soften the ride up a bit, I'm hoping...

YMMV,
Tom

Mon Nov 26, 2007 5:45 pm

On The FV's we pull one spring pack and replace it with a thru rod that acts as the anti-sway bar. That may be too soft for a dune buggy...

Mon Nov 26, 2007 6:15 pm

I found this topic to be quite helpful in understanding the beam construction.

http://www.thesamba.com/vw/forum/viewtopic.php?t=64301