Z4 Rear Sway Bars

T

templed

Member
 Texas
Hey folks,

Semi-newbie here ... used to be on the old z4um, but since that went down a while back, I had been dormant until finding this forum.

So here's the question ... has anyone put an aftermarket rear sway bar on their Z4? My car details are in my sig. Tried doing a search, but didn't get too much. A "how to" with pics would be great if anybody has it.

My goal is not to run the car on the track, but just trying to neutralize the understeer a bit.

Cheers!
 
I have a stock M3 front bar and H&R rear. The car is much easier to throttle steer now, though pushing too hard will still result in under-steer. I'm happy with the results.
 
Thanks Mickey, did you install the bars yourself, and if so did you put it up on jack stands to unload the suspension or just back it up onto ramps?

fire-n-ice ... yeah Beeker's the man, the consumate scientist!!!

Long live muppet labs!!! :thumbsup:
 
templed said:
Thanks Mickey, did you install the bars yourself, and if so did you put it up on jack stands to unload the suspension or just back it up onto ramps?
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Yup, it was a DIY. The car was up on stands. The front bar is really easy to do. The rear bar isn't brain surgery, but it does take a lot of maneuvering to wiggle it through all the suspension, and the space is very tight. (It helps to remove the diagonal cross braces, and ratcheting wrenches are highly recommended.)
 
mmakay said:
templed said:
Thanks Mickey, did you install the bars yourself, and if so did you put it up on jack stands to unload the suspension or just back it up onto ramps?
Click to expand...


Yup, it was a DIY. The car was up on stands. The front bar is really easy to do. The rear bar isn't brain surgery, but it does take a lot of maneuvering to wiggle it through all the suspension, and the space is very tight. (It helps to remove the diagonal cross braces, and ratcheting wrenches are highly recommended.)
Click to expand...

What brand, size, etc., would you recommend looking into Mickey?
 
If you're going to do it, H&R is about the only game in town. ACS and a couple others also make them, but they are stupid expensive, and no better.

I probably wouldn't bother with the front bar. I think the H&R front is too stiff. The M3 bar I'm running is only about 20% stiffer than stock (sport) and I really only did it because I got the bar cheap.
 
Welcome to the forum!

I fitted M3 H&R bars front and rear ( because I have an M3 rear axle ).
I've tried various settings in an attempt to get rid of the understeer. The best setting I found was full hard on the rear bar and one setting up from full soft on the front. The H&R front bar has 3 holes on either side for 3 levels of stiffness but you can mount one side in the middle hole and one in the end hole to give you a setting between soft and medium. The rear bar has only 2 sets of holes but the same principle applies to give you a greater variety of settings.

These settings won't be suited to everyone obviously because other factors come into play such as suspension/steering geometry, other mods, driving style and personal preference but it gives you more options to play around with.

Have you tried removing the dowel on the front strut tops and pushing the suspension inboard as far as it will go? This gives you a greater front negative camber and a bit more "bite" when cornering.

You might want to adjust the steering geometry too. BMW set the cars up to have a bit of understeer because it's easier for your average driver to deal with when it occurs.
 
Thanks Curtis.

I haven't tried removing the dowels on the front strut towers, as I was afraid it might decrease the straigt line stability ... but I guess it's simple enough to try, and then set back if I don't like it.

Sorry if it's a dumb question, but how do you adjust the steering geometry?

I would certainly consider myself an average driver, but understeer is just unnerving. I can handle a little tail swing, but when you turn the wheel and the car doesn't ... it just ain't right.
 
templed said:
Sorry if it's a dumb question, but how do you adjust the steering geometry?
Click to expand...

Not a stupid question, but a very simple answer: alignment. Find a good shop, and let them know what you are trying to accomplish.
 
ive changed both the rears and fronts on mine. rears were able to be done on jacks. Then front on the other hand needed a proper hoist to keep the front wheels on the ground while getting under the car to change the sway.
 
Thanks everyone for the advice,

I decided to take the plunge, and I ordered an H&R rear sway bar. I may still try removing the dowels up front, and my neighbor owns a local BMW performance shop, and I'll talk to him about the steering geometry.

I thought the sway bar just sounded like a little more garage wrenching fun :)

Don't know when I'll do the installation, but if I remember, I'll take photos along the way so that we can get this topic into the how-to section.
 
Great choice on upgrading your rear sway bar. I went with Hotchkis (H-Sport) F/R bars myself, ordered from bavauto.com. They are 28.5mm/24mm in diameter, which is probably the thickest set you can buy for our cars. In any case, the added stiffness will definitely cause a noticable improvement in handling.

Installation can be a bit tricky with the rear bar. I was able to take out the old bar, but couldn't fish the new one through the exhaust because it was so thick. I ended up driving the car to my local shop without a rear sway bar, and then had them install the new one for me. Of course, at that time, i didn't realize that the diagonal cross braces could be removed, so if only i knew that then i probably could have done it myself. Oh well, lesson learned.

Just take your time and follow the instructions. Hopefully your new rear bar comes with new endlinks because it is a pain trying to separate the old links from the factory bar. Another tight spot is trying to remove the bolts that hold the endlink to the control arm -- not much room to work around.
 
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