Swaybars

[midlandtech]

I tried searching but could not find what the stock swaybar measurements are could someone enlighten me?

Additionally has anyone had experience with the turner motorsports sway bar kit:
http://www.turnermotorsport.com/p-103-turner-motorsport-e46-non-m-sway-bar-set.aspx

or is there another kit which performs better/is cheaper

Thanks,

Steve

[Vas]

Those sway bars in that turner motorsports kit are made by h&r I believe.

[Sockethead]

Kpro had turner sway bars on her 325ci and they were too stiff for her liking. The UUC bars on my ZHP are much better according to her...

[midlandtech]

even with the bars set to their softest setting? I love a stiff ride personally. did they perform well atleast?

[HokieZHP]

I was between the Turner bars and the hotchkis but i got a good deal on a set of hotchkis sways so I went with them and I love them. I DD mine btw and don't think they're too stiff. The only noticeable difference was when I put the front bar on the stiffest setting, I had some steering feedback from how stiff it was so I backed it off to the middle setting.

Stock are something like 24mm front and 19mm rear i believe.

[johnrando]

So lets say you want DD with good handling... then are swaybars the next step after springs/coilovers, or instead of, or do them 1st, then springs, or vice versa.... or what? lol. I have the shock/springs, so the answer for me would be after, but I was just curious in general.

Also curious if they would make a big difference after my H&R kit.

[Sockethead]

Well she fell asleep early so I'll aske her in the morning LOL

[midlandtech]

lol thanks.
John, its my understanding that swaybars can increasing handling where lowering the car may not be an option, or can be done in addition to lowering the car to further increase handling. I daily drive my car and it needs to be able to go up inclines and over speed bumps (some of which are quite large) so I am unable to lower my car to the extent that I want to and as such I hoping that a better option to increase the handling capabilities (and hopefully get a little stiffer ride) will be to upgrade the sway bars.

[nike001]

Sway bars are an excellent way to improve handling before upgrading the rest of your suspension. It'll make the car feel a lot stiffer. Sways are one of my next mods because I still have unwanted body roll.

[midlandtech]

Bavauto has some monsters 30 mm front 25 mm rear.... I'm thinking of using that set up.

[Johal E32]

Bavauto has some monsters 30 mm front 25 mm rear.... I'm thinking of using that set up.

Same here. It's pretty reasonably priced too. It costs like $299 w/ bushings.

I think it is 27mm front and 23mm rear

[Crickett]

Since it hasn't been mentioned yet in here, our stock (ZHP sedan) sways are 23.5 mm front & 18 mm rear (I measured). Those measurements concur w/the info from BMWFans.info.

I, too, have been considering upgrading my swaybars & have done some general research. The consensus around the 'net, apparently, is to first upgrade to stiffer springs (& therefore also shocks) to control body movement in both axis (roll & pitch), & then use swaybars to fine tune the car's roll. Of course, that advice is focused on autocross / track use, so keeping stock (softer) springs for DD comfort & using stiffer swaybars to rein in roll isn't a bad idea.

I think that when the time comes, the TMS kit will be #1 on my list (27 mm front & 21 mm rear).

[UdubBadger]

Same, last thing to do to my car outside an SC and LSD


- Goin' H.A.M. Mobile

[UdubBadger]

Is sway install easy on e46? You don't have to drop the subframe do you?


- Goin' H.A.M. Mobile

[derbo]

I believe adding sway bars will decrease roll without sacrificing ride height or ride comfort. I installed UUC sway bars before I did my coilover setup. It definitely improved the handling of the car but still left me wanting more. Of course I went to coilovers after that to further reduce the roll.

[Johal E32]

Is sway install easy on e46? You don't have to drop the subframe do you?


- Goin' H.A.M. Mobile

Could someone chime in here?

Seth, I don't think you need to drop the subframe.. But, then again, I have no idea on how to install them..

EDIT:

This video is perfect! I plan on getting these bav-auto sways anyways!

[LivesNearCostco]

Cricket, good info. I tried measuring my front swaybar once and couldn't decide if it was 23mm or 24mm in diameter. Now I know why!

[derbo]

Is sway install easy on e46? You don't have to drop the subframe do you?


- Goin' H.A.M. Mobile


the front is very easy! The rear can be problematic with adjustable endlinks to get the proper length. Getting the D bracket to bolt up properly was a pain for my UUC bars. Unbolting the rear hangers of the rear exhaust helps give you enough room to install the rear.

[midlandtech]

Good to hear...anyone other than kpro have experience with sways making things to stiff or any other problems?

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[danewilson77]

Could someone chime in here?

Seth, I don't think you need to drop the subframe.. But, then again, I have no idea on how to install them..

EDIT:

This video is perfect! I plan on getting these bav-auto sways anyways!

No video.

[M0nk3y]

Tires corner best when they are loaded equally. There is more cornering force the more you load it, but it suffers from diminishing returns. For example tires with 40%/60% load on left/right will generate more overall cornering force than 20%/80%, even though the overall downward force on both tires is the same.

What an anti-roll bar does is resist body roll by increasing the downward load on the outside tire. Generally it corners flatter but with less grip.

Good article:

http://mgaguru.com/mgtech/suspensn/fs101a.htm



On the street, you'll decrease in ride comfort when you hit uneven bumps (aka a pothole on the left side). A larger bar will reduce the roll and movement, so you'll feel it a lot more.

And this is what happens under high loads with a big swaybar:

http://sphotos-b.xx.fbcdn.net/hphotos-prn1/545066_3666962600898_917273684_n.jpg

http://sphotos-b.xx.fbcdn.net/hphotos-prn1/524244_3666959160812_1202557943_n.jpg

http://sphotos-a.xx.fbcdn.net/hphotos-prn1/524082_3666971761127_48075872_n.jpg

I lift tires because I'm running stock spring rates. Ideally, lifting a wheel is bad, so increasing spring rate and increasing the rebound would be the appropriate action

[Sockethead]

Good to hear...anyone other than kpro have experience with sways making things to stiff or any other problems?

I didn't get a chance to ask her about the settings before she left for work this morning but I know they would of been either in the middle or the softest. She would of tried that first. I will add that she's done something like 45 track days and countless auto-X. She was also an instructor so she's no stranger to track suspensions. In the end I guess it's all personal preference, eh?
What ever bar you go with make sure that it will clear everything if/when you lower the suspension. The Turner bars will clear because Kpro had H&R race springs on her 325... that baby was low! UUC bars will clear too.

Like others said, the rear bar is harder to get out/in than the front... You have to drop the muffler from its brackets and get the back really high to get the bar out. Also it's a PITA getting to the top bolts on the bushing mounts.

[M0nk3y]

Swaybar preferences will vary from person to person. It is not a cookie cutter equation.

I have a 30mm and set it on medium, this reduces more understeer while still having an oversteer oriented car (which is what I want).

However, I need to go to the softest setting on concrete because there is so much grip, my car is too stiff in the front and I get understeer.

[midlandtech]

Awesome thanks for the info guys.

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[UdubBadger]

good info!


I think for the money the TMS kit with adjustable endlinks is the way to go but I'm still intrigued by that bavauto set

[midlandtech]

good info!


I think for the money the TMS kit with adjustable endlinks is the way to go but I'm still intrigued by that bavauto set

I'm thinking I will get the bav auto kit with the big bars and adjust them as needed. Its more money in the end but I am hoping it will be worth it.

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[Torxuvin]

I have the UUC swaybar kit and endlinks. The rest of my suspension is stock. If someone with a stock zhp wants to make a trip to ATL, I can give you a review. I forgot to drive Jon's car before he headed back south. :facepalm

[Sockethead]

I wonder who makes the Bavauto bars you guys are talking about.... they don't make any of their own products....

[midlandtech]

http://www.hotchkis.net/bmw_e46_sport_sway_bars.html

Looks like Hotchkis does

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[Sockethead]

I was going to say "wow they're expensive" but I see they come with adjustable end links for the rear. They were extra $$ with my UUC bars. I also noticed they are hollow bars. That's why the diameter is so big.

We have a Hotchkis bar on the front of the 135... It seems to perform well....

[midlandtech]

I was going to say "wow they're expensive" but I see they come with adjustable end links for the rear. They were extra $$ with my UUC bars. I also noticed they are hollow bars. That's why the diameter is so big.

We have a Hotchkis bar on the front of the 135... It seems to perform well....

Since they are hollow would the larger diameter not indicate an increase in rigidity when compared to a solid bar? Or does their being hollow allow for a larger diameter and thus an increased rigidity as compared to a smaller diameter solid bar?

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[JupiterBMW]

Since they are hollow would the larger diameter not indicate an increase in rigidity when compared to a solid bar? Or does their being hollow allow for a larger diameter and thus an increased rigidity as compared to a smaller diameter solid bar?

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The strength in a shaft or cylindrical bar (such as this application) all comes from the outside portion. Making it hollow barely decreases strength, if any, but greatly reduces weight.

[LivesNearCostco]

I have read that a 30mm hollow Hotchiss swabar is about as stiff as a 28mm solid swaybar, but at a lower weight.

[Johal E32]

No video.

My B.

http://www.youtube.com/watch?v=KwZfLWwB1uM

http://www.youtube.com/watch?v=8LNO69gD7kk

[wsmeyer]

The strength in a shaft or cylindrical bar (such as this application) all comes from the outside portion. Making it hollow barely decreases strength, if any, but greatly reduces weight.

Can't remember the equation for stiffness but for hollow bars you calculate it using the outside diameter and then subtract the "missing" stiffness calculated using the inner diameter. That means hollow bars have to be larger for the same strength but given two bars of equal strength the hollow bar will always weigh less.

[midlandtech]

interesting. Perhaps the hollow bars are not the best route to go then as far as being cost effective.

[M0nk3y]

Can't remember the equation for stiffness but for hollow bars you calculate it using the outside diameter and then subtract the "missing" stiffness calculated using the inner diameter. That means hollow bars have to be larger for the same strength but given two bars of equal strength the hollow bar will always weigh less.

Yep. You got it right

As for solid bars, it's all the same material. Metal is metal


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[Sockethead]

interesting. Perhaps the hollow bars are not the best route to go then as far as being cost effective.
Price out the difference. say, between the Hotchkis and the UUC with the optional adjustable rear links... probably would end up being close... plus the hollow ones weigh less...

[wsmeyer]

interesting. Perhaps the hollow bars are not the best route to go then as far as being cost effective.

I wouldn't think so but it would be interesting to hear other opinions. Couple of things come to mind:

Reducing unsprung weight is always good and all suspension components are at least partially unsprung weight. If you look at A-arms on a car at rest, they would be close to horizontal and it's easy to see that half the weight would be on the suspension (unsprung) and half the weight hanging from the chassis (sprung). Sway bars would be a bit more complicated as most of the weight would be hanging from the chassis - sprung.

Considering how low they are on the chassis, and that they are below the center of gravity, I don't think the difference in weight would have much of an effect on the car.

For any part that moves with the suspension, both the force required to overcome it's inertia, and the force required to overcome it's momentum, cannot be absorbed by the suspension and are transferred to the chassis.


William.