Swaybars & the best way to attach them???

[xelderx]

This is a question I have that could be very pertinent to my AutoX build (link here). The car I'm building opens up a new option for me and I would like a few opinions on what people think is the best setup.

The components involved are my '94 Protege chassis/stock sway bars and my 3rd Gen AWR coilovers. On the '94 chassis the swaybars are connected to the control arms. On the 3rd Gen Proteges the swaybars connect to the strut housings. I can see the benefit of the sways connecting to the control arms, especially in the front, since you wouldn't have to worry about the extra movement of the strut housing rotating with the wheel assembly while turning. It seems that changing the mounting points for the ends of the swaybars relative to the LCA pivot point would also change the effectivess of the bar. i haven't really sat down and thought about it, but I have the option of connecting the sway bars to either the struts or the control arms. I'm just trying to decide which would be the more effective solution. Both ways would utilize Hiem jointed endlinks.

 

[thewrench]

All things being equal, I'd say it wouldn't matter, but of course all things aren't equal. The farther away the mount point is from the LCA pivot, the more leverage you get on the sway bar, ie less effective, but you get more travel. Closer to the pivot you get less leverage, but much less travel. It's going to come down to trial and error no matter how you look at it.

 

[apexlater]

I believe I read somewhere that ideally the endlinks should be as close to the hub as possible.

That said, it sounds like you are limited to endlink location based on the bar arm. I'm voting control arm since it may be easier to keep the endlink from being at a funny angle. Basically if the lower control arm is parallel to the ground, and the swaybar arm is parallel to the ground/lca, you can make the endlink perpendicular to them.

Are you going to use a "pogo" style endlink if you connect to the lca? If that's the case then I vote on the strut so you can use heim joints on both ends.

Otherwise you would have to make a bracket (like on the Miata).

 

[low_psi]

I vote mount them to the control arm. Easier to get to when balancing the car and you're keeping the CG low

 

[gavin_leslie]

If you have the ability to do so mount on the strut. This will be the most effective for a couple of reasons.

If mazda designed the 3rd gen protege as they have for the rest of their strut suspended cars, then the strut draws a line that centers on the lower control arms ball joint. As the suspension rises the hub and the strut move in tandem with the kingpin in a 1:1 motion ratio. This is what you want to piggyback off of.

With the swaybar on the arm it has less leverage on the motion of the hub/wheel and the motion ratio will be somewhere in the .4-.5:1(?) ratio. With a swaybar connected to the arm youll need a thicker/heavier swaybar to approximate the same wheel rate as a swaybar connected to the strut. The range of movement is also greater with the swaybar connected to the strut giving greater resolution wrt the addition of spring rate from the swaybar. There is also less fatigue on the mounts of the control arm moving the swaybar off them(Ive had this issue on occasion). Granted, with high spring rates there wont be too much movement but the effect is still there, just muted.

Gavin

 

[xelderx]

Awesome replies so far guys. I'll be mounting the front struts on the car this weekend and I'll have a better idea what kind of angles are involved between the end of the swaybar and the strut housings. My AWR coilovers still have the endlink mounts on them so I'll just have to see if the angles are good enough to keep things from binding. I will have to make a bracket to connect a Hiem joint to the swaybar in either case, but that shouldn't be a problem. It's a pretty simple swap to go back to the stock LCA mount if I wanted to test it both ways back to back. Gavin, thanks for the geometry lesson. Of all the things I know about setting up suspension, I don't know much about the math and theory involved. Will Kalman ran the springrates on his Escort completely backwards from what I ran on the 3rd gen Protege which has me thinking about flipping my springrates around and giving it a try.

 

[Auto-Xer]

Will Kalman ran the springrates on his Escort completely backwards from what I ran on the 3rd gen Protege which has me thinking about flipping my springrates around and giving it a try.

You may have seen this, but here is Will's 'Recipe':

Ground Control camber caster plates
--Front was off-the-shelf
--Rear was a set of GC plates that I customized to fit

Ground Control Advance Design struts - pricey along with custom housings made by GC.

Spring rates 600#F/500#R

Suspension Techniques front sway bar
Quickor 1" rear sway bar

Front lower tie bar - custom by a friend (who will make more) - this is really worth it on this chassis
GAB upper strut bar

Mazdaspeed rear strut bar

Pacesetter ceramic-coated headers

K&N Filter on a cut-away stock air box (relocated battery will help in this area when I have time to get to it)

Odyssey PC680 battery relocated to the rear

http://sccaforums.com/forums/thread/157763.aspx

I'll be on 500/450 springs to start with on my STS ZX2...and we'll season to taste from there.

 

[thewrench]

I guess just to add a little. Since you're using the stock bars, if you move to the strut mount and it is appreciably farther away from the LCA pivot, you will get greater leverage on the strut bar effectively weakening the strut bar. Also, if that endlink ends up at some weird angle I'd think you'll lose some of that leverage due to the angles changing during suspension movement. I'd say mount it at the location that gives you the best angles, that is nice right angles, that won't change much during suspension movement, which since you're using the stock sway bar, I'm guessing will be the control arm.

 

[xelderx]

I'll probably be upgrading to the swaybars that Kalman used and keep the stock front one handy just in case I don't like the larger front bar. I liked to adjust the attitude of the protege5 mid corner with the throttle which is why I kept the stock front bar in the Protege5. We'll have to see how the BG chassis responds and what I end up doing with the spring rates. I've been driving a lot of different chassis lately so I shouldn't have too much trouble adapting to whatever the car wants to do.

 

[xelderx]

You may have seen this, but here is Will's 'Recipe':


http://sccaforums.com/forums/thread/157763.aspx

I'll be on 500/450 springs to start with on my STS ZX2...and we'll season to taste from there.

I've traded a few emails with Will over the last year or two. After seeing his underpreppared for FSP car in person in Topeka 2005 I started to put this project together. Luckily, some of the real expensive stuff from my Protege5 fits legally on the BG chassis which makes this a pretty easy build. I need to get the damn thing finished so I can do some testing with it before summer.


Let me know how those spring rates are working for you. I like a pretty loose car. I would set the protege5 up to basically spin on anything other than the right temp tires.

 

[Auto-Xer]

Let me know how those spring rates are working for you. I like a pretty loose car. I would set the protege5 up to basically spin on anything other than the right temp tires.

I'll be happy to share anything we figure out. I can say this--I understand that the ZX2 comes with a 25mm FSB, and that is what I expect to find on my car once the snow melts. The rear looks to be about 22mm and is a 3-way. We just got some new front LCAs and did poly bushings on those, and I just ordered some Cusco camber plates for the front, and front and rear lower tie bars. I still want to do poly steering rack bushings yet (have parts) as well.

We'll start with that, and if need be we can do all poly in back as well, but I think the car will be more forgiving (and still pleanty rotateable as-is).

 

[xelderx]

I got part of the front suspension mounted and it looks like I can attach the swaybars to the struts very easily. The angle is pretty much straight up and down for the endlinks. I'll just need to get some shorter ones. This ought to be a much stronger setup than the skinny bolt through the control arm.