bushing questions

[hotwhip9]

what are the pros/cons to all poly and poly/rubber bushings, particularly for the lca.

[dochidalgo]

Well, my car has installed Prothane polyurethane bushings & end links, plus the polyurethane in the LCA's and panhard bar...the good thing is the better suspension performance, a firmess feeling. The bad thing (no too bad, really) is a little more vibrations transmited to the cockpit...you will get used to it
Take care
Doc

[hotwhip9]

which bushings will last longer?

[Dave M]

rubber will eventually wear out as it is subjected to road grime, salt, oils, etc... polyeurethane will last darn near forever as these chemicals don't affect poly nearly as much. Poly will give you a firmer ride and slightly better performance than rubber because it's stiffer, but that stiffness causes more vibrations than rubber. That's the tradeoff. Ploy/rubber combos try to get the best of both worlds with one bushings being rubber to dampen the vibration (usually a harder rubber than stock to keep up in the performance category), and a poly bushing to reduce deflection.

It's really personal prefernce and what you're looking to get out of the car. If it were me, I'd just stick to the all poly bushings, but I've never felt or personally experienced what a poly/rubber equipped car rides/performs like.

You won't be disapoointed with all poly.

[dochidalgo]

The poly for sure. The trick is the lubrication with silicon base not petroleum.
Spohn sells the right one (another autoparts stores must have it too,I guess).
The cornering is much better with polyurethane in your LCA's, more control feeling because it is so.
I'm not expert, my experience only, but I hope helps you to decide.
Doc

[hotwhip9]

these are the ones i was looking at Anyone hear any good/bad things about these? or these:choice 2 which ones would be better? or would these adjustables be better?

[dochidalgo]

BMR is a reliable brand. The tubular one seems the better (why?..donīt remember) but I purchase mine from http://www.spohn.net/category.cfm?categoryid=1041 .
If you're planning to low the car the adjustable is the option.
I strongly recommend to you the relocation brackets..
Doc

[Dave M]

I've heard nothing but good things about bmr. That's what I'm planning on using. I'd reccommend them.

I've heard great things about spohn too.

[Injuneer]

BMR is one of the leading producers of 4th Gen suspension parts. Quality and value for money is very good. I personally prefer Spohn, but they are both good.

You need to determine what kind of perfromance you place a priority on.... for "straight-line" traction, you want the bushings to be as stiff as possible, even going on to metal "rod ends" for the ultimate performance. For vigorous street driving, with ultimate cornering power, very stiff bushings can cause a problem. As the body starts to roll, the bolts at the body end of the LCA are no longer parallel to the bolts at the axle end. If the bushings are extremely stiff - e.g. both ends polyurethane - the LCA will start to "bind", limiting suspension compliance.

The rubber/poly combination overcomes the "bind" problem, with the rubber allowing for a greater misalignment of the front and rear mounting points. Actually, the metal rod ends will prove superior in this case as well, with the "spherical" bearing allowing the front and rear bolts to be out of alignment to a greater degree, with no resistance whatsoever.

Downside of the metal rod ends it serious noise, and limited life. Spohn uses the top-of-the-line QA1 spherical rod ends in all his products, hence one of the factors that causes me to prefer Spohn. You might pay a bit more, but you get what you pay for.

Another combo to consider would be a poly bushing on the body end of the LCA, and a rod end on the axle end.

Is there any particular reason you are looking at the chrome moly? The cost is much greater, and there is very little weight to be saved with the chrome moly.

Boxed LCA's are simply "overweight" in my opinion. I use Spohn tubulars for an 800HP nitrous application. A friend of mine runs the Spohn tubular on a 97 30th SS convertible that is running 8.6@160mph.... aver 1,300HP. The tubulars are really strong enough, IMHO.

[hotwhip9]

the car is lowered, and I am going to order the relocations while I'm at it, and my thinking is since its going to be apart anyways, why not put a new lca in. Injuneer, the chrome moly, well its what I clicked on, is it good?! lol. so it seems the tube adjustables would be the way to go? And I would get the new hardware kit for it so I don't have the frustrations of the old bolts.

[Injuneer]

Chrome moly is a stronger steel, so they use a thinner wall thickness in the tubing - 0.120" for mild steel, 0.083" for chrome moly. They end up with a lighter LCA, but with the same strength as mild steel. But the weight savings isn't all that great. You might save 30% on the tubing, but the ends are going to weigh just as much. If you were trying to get a 4th Gen under 3,000#, it might be worth it. I figure I save about 30# using chrome moly tubing on my roll bar, but thats probably 20X what you will save with LCA's.

You probably do not need an "adjustable" LCA either. There is nothing to "adjust", unless you have something bent in the rear subframes, and need to correct the "thrust angle".... but that would be the hard way to do it. I used adjustables to move the rear axle back a bit, to gain clearance for 28" slicks, so if you plan to eventually be over the 600-700HP level, they might be of interest.

Mild steel, tubular, non-adjustable. Poly/Poly ends for drag racing; Poly/rubber ends for cornering, with minimum noise; poly/rod end for cornering or drag racing with a bit of extra noise.

The Spohn LCA's in this pic are poly/poly adjustable, but have since been replaced by all spherical rod end adjustables.



Spohn tubular adjustable w/ rod ends under 8.6-second SS: