Upgrading to m3 drop links worth it?

[VinniE30]

Found some good info on this at s14.net

sure its there for 3 reasons
1. it changes the actuation rate (wheel movement / ARB movement)
M3: 0.9; E30: 0.562 which means on the M3 the same wheel movement twists the rollbar MORE, i.e. making it act like a thicker, harder bar
2. Saves a little weigth: the strength of the M3 ARB (19mm strut-linked) corresponds to a E30 ARB (24 mm wishbone-linked) with the same geometrical dimensions.
3. saved BMW mucho money by reusing existing cheapo E30 parts

http://www.s14.net/forums/showthread.php?38723-Modifying-Strut-tubes-and-relocating-sway-bar-mounting-points

[acolella76]

Wow, nice find!

[bastianshaw]

agreed thanks

[bastianshaw]

is it ok to weld the m3 bracket on the strut tube w the shock still installed?

[JGood]

is it ok to weld the m3 bracket on the strut tube w the shock still installed?

I wouldn't do that, I'd be afraid of what the heat could do to the seals and the oil.

[woc]

stupid question: how about the off centered lolipop bushing on m3s? They have it as an e30 upgrade in some sites, I wonder why that is?

[JGood]

stupid question: how about the off centered lolipop bushing on m3s? They have it as an e30 upgrade in some sites, I wonder why that is?

They increase caster, which increases straight-line stability. They will offset the wheel forward in the wheel well.

[SkiFree]

stupid question: how about the off centered lolipop bushing on m3s? They have it as an e30 upgrade in some sites, I wonder why that is?

caster... Look at shock angles on newer BMW's. These offset bushings were some of the early examples of BMW adding caster.

** EDIT: beat by one minute... dang.

[nrubenstein]

stupid question: how about the off centered lolipop bushing on m3s? They have it as an e30 upgrade in some sites, I wonder why that is?

It adds a bit of caster, with the consequence of a bit more bump steer. Not necessarily better, so much as different.

I expect that the reason that racing engineers would prefer a control arm mount is that the control arm only really moves in one dimension. The strut moves in two or three. When you have full control over spring rates and dampers and sway bar sizes, the control arm mount IS less complex.

As noted, though, you get a lot more stiffness out of a given sway bar when it is connected to the strut.

[bastianshaw]

so bars are installed im still debating which way to go on the front links, I have both types, if i have to remove the strut to weld the housing ill prob run the CA links...I dont see any need for reinforcement on the control arms, i get the trailing arms could be stonger but do i really need to reinforce the front CA?

[JGood]

so bars are installed im still debating which way to go on the front links, I have both types, if i have to remove the strut to weld the housing ill prob run the CA links...I dont see any need for reinforcement on the control arms, i get the trailing arms could be stonger but do i really need to reinforce the front CA?

No, nothing needs to be done to the front control arms.

One other consideration for the control arm vs strut mounting location, is the fact that some of us are low enough that the end link binds up when mounted to the control arm, and the sway bar is at a very bad angle, even when the car is sitting still. Going to an adjustable link with the strut mount allows us to get the swaybar back to horizontal.



The angle of the swaybar pulls the top of the endlink sideways, flexing the lower bushing, and the casing of the bushing on the end link ends up jamming up against the control arm mounting bracket, effectively bringing swaybar movement to a stop. I noticed this on mine, the metal on the end link and mounting bracket got all mashed up. So I bought adjustable M3 links and the strut mounting tabs.

[acolella76]

No, nothing needs to be done to the front control arms.

One other consideration for the control arm vs strut mounting location, is the fact that some of us are low enough that the end link binds up when mounted to the control arm, and the sway bar is at a very bad angle, even when the car is sitting still. Going to an adjustable link with the strut mount allows us to get the swaybar back to horizontal.


The angle of the swaybar pulls the top of the endlink sideways, flexing the lower bushing, and the casing of the bushing on the end link ends up jamming up against the control arm mounting bracket, effectively bringing swaybar movement to a stop. I noticed this on mine, the metal on the end link and mounting bracket got all mashed up. So I bought adjustable M3 links and the strut mounting tabs.

Not trying to pick on you or anything, just using that picture as an example, but look how *almost* horizontal the control arm and tie rod are in that picture. IMO fixing the angle of the control arms should be more important than fixing the angle of the sway bar

[woc]

Please pic document your links instal. I just received a bunch of boxes from IE with their sways and adjustable links, new shocks, springs and etc. I noticed some triangular tabs with the links, and I can already feel how puzzling the whole instal will be. I'm going to have to come here for questions and look at pictures there are no instructions whatsoever with the items, and I still need to deal with the rear sways + weld on blocks too. Anyone have pictures with those installed? thanks.

[JGood]

Not trying to pick on you or anything, just using that picture as an example, but look how *almost* horizontal the control arm and tie rod are in that picture. IMO fixing the angle of the control arms should be more important than fixing the angle of the sway bar

For a track car build, sure. For a street car, simply swapping over to M3 links solves the binding problem. I have no desire to build or buy a custom front control arm setup with high maintenance spherical links. And I don't think the control arm not being horizontal is nearly as much of a problem as the swaybar being fully locked and binding, metal on metal. What you can't see in that picture is the bottom end link bushing is being twisted very hard forward/rearward, hitting the bracket.

I have an m60 powered car, with the front subframe spaced an inch down from the body to get correct drivetrain angle. To get the body lowered back down an inch, I drop the coilovers an entire inch inch further down just to achieve the same ride height as a normal e30, which moved my control arms even further from horizontal. I was binding my end links while sitting still. But guys who go VERY low will have the same issue I do.

I just swapped over to M3 links today, problem solved.

[acolella76]

Well, that's part of the problem. The more horizontal (bad) your control arms are, the lower your roll center is (bad) and the farther away it is from your center of gravity (also bad). The farther away your RC is from your CG, the less force is needed to make the car roll. ie even though you've lowered your car and effectively have a stiffer sway bar, I would be surprised if the car rolls any less than it did from the factory.

Adding the links to the struts can also introduce binding issues unless you have, like Justin above me, bought adjustable end links. Turning the wheel will also pre-load the sway bar too. So why buy adjustable end links to eliminate pre-load when you're just gonna put it somewhere else? Another thing I've heard drivers complain about is they feel a little 'lag' in response time of the sway bar when it is mounted to the strut. Being the divas that they are, I tend to ignore them, but who knows. Like someone else in this thread, the control arm mounts only move in one dimension and are more direct. Another thing to be careful of is having a sway bar that is too stiff. Lifting tire may look cool but it is inefficiency at its finest when only one out of two tires needed to steer the car is on the ground.

So no, OP, I do not feel it is worth it for you to mount your sway bar to the strut. If you want to combat roll, correct your roll center or get stiffer springs.