Any good reason to change lca

I mean good as in something other than new ones might be a bit stronger.

Rather than a lot of anecdotal reports, I'd like some solid technical insights into why changing might be a worth while consideration. After reading a lengthy discussion about poly-poly ends, some time ago, I'd have to say that I am very leary of that setup, becauseo f the potential to introduce bind into the rear susp.

What I want is something that can be demonstrated both theoretically and practically to improve overall handling/traction. If I were to go down this road, what would be my best choice? rubber/rubber in a harder durometer?

BTW, I use the car for a little of everything, but autox and lapping are my favorite pastimes.

http://www.jonaadland.com/Lca1.jpg

http://www.jonaadland.com/Lca2.jpg

http://www.jonaadland.com/Lca3.jpg

http://www.jonaadland.com/Lca4.jpg

Janny,

Here is another link for you to take a look at:

http://www.geocities.com/motorcity/1701/bushings.htm

It basically says the same thing Jon explained in his diagrams but it also addresses some of the common criticisms the stock LCA's recieve.


Jon,

Don't tell me you just had those laying around? ;)

While I have your attention I have a question of my own. Is there any disadvantage of using a rubber/poly bushing on one end of an LCA provided there is a rod end on the other? That should save some cash in the long run since there would only be 1/2 as many rod ends and it might help with NVH a little.

I figured the single rod end on each side should allow enough rotation to minimize bind but maybe I'm overlooking something...

Thanks!

Thanks guys!

That is exactly the kind of info I was looking for. I hate buying stuff just so that I can say I've got it, and then finding out later on that I've done more damage than good by taking that action. I was 16 once too. I bought every peice of crap that the local hot rodders and shops were pushing. I ended up with a car that was such a piece of sh&* that I couldn't stand to drive it. So I sold it.

So are the 1LE trailing arms still available these days?

Thanks!

makes me glad i got those 1LE RLCAs from SLP

also got BMR relocation brackets set to the lowest hole,
heard it might not be good for autox, i'm gonna put em in the middle hole this week.

Originally posted by Janny
Thanks guys!

That is exactly the kind of info I was looking for. I hate buying stuff just so that I can say I've got it, and then finding out later on that I've done more damage than good by taking that action. I was 16 once too. I bought every peice of crap that the local hot rodders and shops were pushing. I ended up with a car that was such a piece of sh&* that I couldn't stand to drive it. So I sold it.

So are the 1LE trailing arms still available these days?

No problem, glad to see someone willing to think for themselves for once. I brought up this same issue in LT1 Tech today and its already been dismissed since I'm "overanalyzing" the problem :rolleyes:

<rant>
I should go in to business making half-assed tubular suspension parts since obviously no one cares about their suspension working properly.
</rant>

Anyhow, like MrBigXL metioned the 1LE's should be available from SLP. I think I paid $80 for mine a few years back. Otherwise they are GM p/n 10164151 if you want to try dealer.

I appreciate the "analysis" as well. I've got a stocker for now, but am interested in starting to autocross/road race in the next few years as time (family & career) and money (family ;) ) allow.

The article certainly makes sense to me. It's amazing how my dad's comments (he's an aerospace engineer) when I was a kid about not screwing with the factory set up for a car ring true most of the time. Ahh, the things we learn after we get old enough to actually listen.

Originally posted by MrBigXL
Thanks!

makes me glad i got those 1LE RLCAs from SLP

also got BMR relocation brackets set to the lowest hole,
heard it might not be good for autox, i'm gonna put em in the middle hole this week.

I put in the SLP Level I suspension kit with Eibach and Bilsteins. This lowered the front of the car about 1/2 inch front and the rear about 1 1/2. It definitely improved the "feel" of the car but after reading a bunch of stuff here, I decided it was best to correct the geometry of my car with the lca relo brackets. I got them from Spohn. Weld in types. With the lca's in the middle hole, they are almost level; they have a slight upward cant, towards the front of the car, of about a 1/4 inch over the length of the lca. The difference in grip when accelerating out of a corner was quite phenomenal.

So, all this is to say, I think you are making the right decision.

Originally posted by jwade95Z
The article certainly makes sense to me. It's amazing how my dad's comments (he's an aerospace engineer) when I was a kid about not screwing with the factory set up for a car ring true most of the time. Ahh, the things we learn after we get old enough to actually listen.

My buddy who's a Class A Mech, always cautions me about going too far from factory setup as well. In 30 years of turning wrenches, he has seen untold numbers of incidences in which deviating too far from original engineering standards leads to unpleasant and unintended consequences. Machines are engineered to work as a whole. Alter one part, and there is no telling how the whole will react. I generally listen carefully to his advice on such matters.

Originally posted by Soma07
Jon,

Don't tell me you just had those laying around? ;)
Actually I did. I whipped them up a couple of years ago to prove, mathematically, to a guy on the Corral that Global West's claim for their Mustang LCA's of having "Zero Lateral Deflection" as well as "Zero Bind" was a tall Jantastic! tale.... (Thus the Mustang geometry in the pics--but the same thing applies to us.)
While I have your attention I have a question of my own. Is there any disadvantage of using a rubber/poly bushing on one end of an LCA provided there is a rod end on the other? That should save some cash in the long run since there would only be 1/2 as many rod ends and it might help with NVH a little.

I figured the single rod end on each side should allow enough rotation to minimize bind but maybe I'm overlooking something...
You aren't overlooking anything. Having a rod end in just one end of the LCA eliminates 80%-90% of the bind compared with a Poly/Poly LCA. One rod end is enough to give the freedom of rotation as shown in the first two pics--and that's where most of the bind is. But as the last two show, in addition to rotating the LCA needs lateral freedom because during body roll it will no longer be perpendicular to its bracket in the plan view. A rod end at one end not only gives you the freedom of rotation but it gives you this freedom at one end as well. The little bit of bind you're left with is only the lateral movement at the one poly location.

Those are the reasons I originally went with poly/rod end combo LCA's. However, now that I've switched to rod ends all around I can hardly tell a difference in NVH. One rod end is enough to add a bunch of it.

In fact, my rod ended LCA's (with quality rod ends) are much more quiet than the Poly/rod end combo LCA's were using cheap rod ends. But they are slightly louder than the poly/rod end LCA's using quality rod ends.

Only having to replace two rod ends at a time definately will save money. I still think it's a good set-up.

Thanks Jon! :)