procainestart
procainestart Dork
3/22/10 6:40 p.m.

How do roundy-round stock cars keep springs in place when the suspension goes to full droop? I'm talking about non-coilover stuff here.

I need to nix my Saab 900's home-made Custom Spring Perch v1.0 for v2.0. Both versions use cheap stock car weight jacker hardware with adjustable screws. Problem is that while v1.0 springs can't fall out in full droop, the springs on v2.0 are shorter, merely sit on the perches, and could liberate themselves should I get the car airborne.

I looked at some roundy-round catalogs and didn't see anything being sold to keep the springs in place (I assume they have the same issue.) Can I simply add some stout safety wire to keep things (mostly) in place? The lower perch is long enough so that the spring can lift ~1.5" before becoming unseated, but the upper perch has only a ~1/2" collar. Note that my set-up is not a coilover design and overall spring length is a consideration, so adding helper springs might leave the ride height too high.

Wally
Wally GRM+ Memberand SuperDork
3/22/10 6:59 p.m.

We attached a short piece of chain from the axle to the chassis limiting the amount of drop and put small metal guides in the spring perch to keep them centered

Nashco
Nashco SuperDork
3/22/10 7:21 p.m.

Limiting straps? Duct tape? Bungee cord? Longer spring with variable rate or dual springs? Should I ask more questions?

Bryce

mw
mw Reader
3/22/10 8:08 p.m.

I would vote for the chains to limit wheel droop. You would be shocked how well this works. I know I was. A friend of mine did this on his 95 Impala SS. He autox's the car and is stupidly fast with it and no one can believe how well it handles. It's been two years and he hasn't had any problems.

Knurled
Knurled GRM+ Memberand New Reader
3/22/10 8:12 p.m.

I have successfully made limiter straps out of old seatbelts. You need to at least triple fold where you put the through bolts.

procainestart
procainestart Dork
3/22/10 11:15 p.m.

Thanks for the responses. Turns out at full droop, the spring only drops ~1" down the jackscrew, which protrudes down ~3". I'd recalled the springs as being much shorter than they are (long-dormant project).

Wally
Wally GRM+ Memberand SuperDork
3/23/10 6:08 a.m.

Nice job on the jackscrew. Can we see a picture from the top?

turboswede
turboswede GRM+ Memberand SuperDork
3/23/10 9:35 a.m.

Zip ties on the upper or lower coil. Holds the springs in place, allows for full suspension travel.

iceracer
iceracer HalfDork
3/23/10 10:35 a.m.

Tender springs are sometimes used.

procainestart
procainestart Dork
3/23/10 9:01 p.m.
Wally wrote: Nice job on the jackscrew. Can we see a picture from the top?

Thanks, Wally. Here's a pic:

The top sits beneath the car body, pressed against the stock spring seat. I took a stock bump stop (pics below), which ordinarily fits between the car body spring seat and the spring, and cut it down. Using this piece allowed me to place the top portion of the jacker set-up without cutting/welding the actual car. Next, I welded on a slice of 4.5" OD pipe and then the jack plate, making a "sandwich" of sorts.

I'm using a slice of PVC at the top to keep the spring centered on the perch; on the bottom I had a fab shop bend up pieces into a "C" shape, then I welded on short lengths of pipe to hold/center the springs.

Using the current set-up (5" OD springs), the weight of the car and spring length keep everything secure. When the 2.5" springs go on for good, I'll fasten the top plate so it stays in place. Stock spring OD is 5.5" so I get a lot more room for tires.

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