Suspension Setup. Comments Welcomed!

[98goldbird]

I'm going to be upgrading my suspension with the tax return I'm getting, and I was wondering what others comments are.

Sway Bars
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GM 1LE - Front is part number 26032907 and is 32 mm, rear is part number 10021221 and is 21 mm. With the 1LE sway bars you will also need endlinks, these are part number 10221779.

LCA
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GM 1LE - Part number is 10164151 for the set.


Pan Hard Rod
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Will be the Adjustable one (since my car is lowered) from either Hotchkis or BMR (Kinda heard BMR isn't up to par on these, so probably Hotchkis)

Strut Tower Brace
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Will either be the SLP V8 one or the BMR one.


Opinions??

[PewterBird]

Sway bar will definantly stiffen things up. I just installed on a week ago, and it is night and day. It definantly keep the car flat around corners.

Go ahead and buy endlinks before hand. Most likely you will break them taking them off.

[Dominic]

I run 1LE Sways, poly endlinks, 1LE LCAs, 1LE panhard rod, BMR STB, and Bilstein shocks on a custom alignment. The car handles beautifully and rides simply great.

[FireFighter]

Nice choices, Look around on ebay. I got my front 1LE bar on their for 27 bux plus 15 for shipping.

[HAZ-Matt]

I don't see how the STB does much of anything on an everyday Fbody, or even one that is driven in a spirited manner through some corners.

Injuneer:

One could argue that the "cornering load" taken by the upper A-arm in the 4th Gen's unequal length A-arm suspension isn't a whole lot different than the cornering load taken by the 3rd Gen upper strut mount. The 4th Gen concentrates the upper A-arm load, and the upper spring seat load concentrically at the top of the shock tower. Its likely that the brace could prove beneficial, when a drag car, without a front sway bar, tries to pull the front wheels - drivers side wheel first because of the reaction to the torque at the passenger side drive wheel.

The brace isn't going to do much of anything under "normal" driving conditions, but at the extremes of cornering, or pulling the front wheels in the 1/4-mile, it will come into play. Interestingly, some of the Auto-X and road race people don't like the upper shock tower brace, because they claim the added rigidity of the front end makes the transition to break-away more extreme, and less predictable.

mitchntx

The forces applied start at the tire's contact patch.

Assuming 100% side loading traction the force is transferred to the hub assembly. Becasue the contact patch is almost a foot below the hub, the wheel tries to pry away from the hub, like when you use a church key on a bottle of beer.

Becasue the forces are below the mounting point, the majority, if not all, the lateral force moves to the lower ball joint, because the wheel is still trying to pry away from the suspension.

This is then transferred along the lower A-arm and into the K-member.

The upper A-arm is nothing more than a stabilization point to keep everything in align. The stamped, sandwiched inner fender is well suited for this job.

But let's look at real life, instead of the hypothetical 100% side loading.

When negotiating a turn, the wheel turns about 15* or so at full lock. Again assuming 1G and no braking, the cornering weight of the car is spread between the front and rear wheels ... in actuality, the front carries more because the front tire is scrubbing against the pavement in order to change directions, but this is all hypothetical, right?

The loading forces are transferred the same way, however ... we now have the wheel turned. So the forces are transferred more rearward than laterally. Could this be why the A-Arm has the rear mounting point BEHIND the the tire's contact patch? I'll go out on a limb here and say ... YES!

Now, all that to illustrate that if the upper mount is so flimsy it flexes, tieing the 2 points laterally does no good because the forces generated are longintudinal, not lateral. But because the forces are so minimal, anything is overkill ...

One I hadn't considered ... a wheelstand. As the car comes down, the suspension compresses with minimal loading to the contact patch.

If the susension bottoms out, it will either nail the bump stops (on the front frame rail, I believe) or bottom out the shock.

If the bump stops are removed and the shock bottoms out, the lower shock mount is the weak link, it would appear to a casual observer. Those 2 8mm standard grade bolts couldn't take too much shear forces.

If you have not removed the bump stops, the forces are transmitted to the bottom of the frame rail and come nowhere near stressing the upper shock mount.

whew ... that was way too much thinking for a Monday morning.

Bottom line ... an STB is $100 and your speed shop of choice will love you for buying one ...

Although the alternate point of view is
Z28barnett:

So in summary, in a hard turn the inside tower is doing little and the outside tower is being pulled toward the the outside of the turn. The STB bar can then increase the stiffness of the ouside shock tower by sharing the load through tension with the mostly unloaded inside tower.

The static anaylsis tells you where the forces will go, but a dynamic analysis tell you what they will do. If both wheels had the exact same traction the STB would not do anything it would just be displaced left or right. In a hard turn this doesn't happen due to the weight shift towards the outside tire.

As long as the STB bar is stiffer in tension than the shock tower is in bending, it will have an effect. This is pretty likely since everything is stiffer in tension than in bending. Thats why we have suspension bridges.

The STB should only help when you make hard corners, the harder you turn the more the effect. It might be a little help if you where lifting both front wheels, but mostly it is along for the ride until you turn.

I can see why you think the STB is doing little but I am pretty sure it is doing more than you give it credit for. The Miata factory "R" version from a few years ago had an STB and it is true double a-arm suspension no struts. They didn't put it on for no reason.

http://web.camaross.com/forums/showthread.php?t=307928

As for the rest, the sway bars are going to depend a lot on the spring rates. What is the difference between the front and rear Hotchkis springs? That 21mm rear bar is probably too big.

LCA's and panhard are fine.

[Dominic]

Well personally, I can tell a difference in both autocross and normal cornering with my STB. I prefer to have it than not, especially since it doesn't add any weight or harm anything. It might not be 100% necessarry, but neither are SFCs are they? It does make the car more rigid.

21mm bar too big? Come watch me autocross. I tried a 19... the 21 works best for me. It all depends on the driver.

[V6Bob]

"I tried a 19... the 21 works best for me. It all depends on the driver."

You know I've gotta disagree on that one. :D

Any driver could adjust their style to get on the gas earlier and go faster with a smaller rear bar. The 21 just transfers too much cornering load back and the rear tires can't both corner and accelerate at the optimum rate. The really fast V8 guys know this (few of them use 21s unless they have huge front springs), and it's even more true with the V6.

Your opinion may vary.