Optimal Sway bar Deflection....

[IronFreak]

Obviously going to a larger sway bar is critical for counteracting roll of the vehicle. My questions is....Is there a minimal amount of deflection required in a sway bar, can they be too stiff? They tie one side to the other, but each side still needs to work independently of each other.

I know that most E30's use a solid bar bent to conform around the body, But I have seen other vehicles were clearance wasn't an issue, their aftermarket sways are built from chromoly and other hard, high tensile strength materials that I can't imagine would offer much deflection.

If you STIILLL haven't picked up where I'm going with this....I do a lot of custom fabrication and I was going to take a whack at building my own sways...I did some on my jeep.

Educated input please......GO!

[IronFreak]

Come on, I know there are some guys on here that can chime in....

[JGood]

It depends on the rest of your suspension setup, the rest of the chassis mods, the use of the car, and the driver preference.

Just as with spring rate, there is no optimal number, it depends on other factors.

Considering the variety of aftermarket bars available, I can't see the benefit of making your own, other then something fun to do.

To answer your question, yes, a sway bar can be too thick. In theory, they *should* only be used to fine tune F/R balance. Roll control should be done via the coil springs, not the sway bar. But, for a street car, you end up with very stiff suspension that way. So the sway bar is a way to reduce body roll without making the suspension painfully stiff.

[IronFreak]

Im building it for autox and track use primarily, it will be used on the street, when i feel like tooling around, but in no way will it be a DD. a list of thing that are or will be done....

Engine bay and chassis seams stitch welded
Treehouse cabs
Koni adjustables f/r
Eibach coilovers 550 front 650 rear
IE camber plates (race)
GC rear shockounts
Condor and akg bushings (everywhere)
Custom strut bars
Few other custom items ill wait to share

It would basically be for fun, and to be able to say i built them. I was thinking a chromoly front at 21ishmm, and a rear at 19mm

[JGood]

Sounds like you already answered your own question. 21/19 bars are already available, as well as thicker and thinner bars. If you want to try making your own, go for it. I wouldn't think you'd want to go any stiffer then a 21/22ish though.

You can also mount the stock style sway bars on the strut housing using M3 style tabs, which will significantly increase sway bar stiffness.

[IronFreak]

Sounds like you already answered your own question. 21/19 bars are already available, as well as thicker and thinner bars. If you want to try making your own, go for it. I wouldn't think you'd want to go any stiffer then a 21/22ish though.

You can also mount the stock style sway bars on the strut housing using M3 style tabs, which will significantly increase sway bar stiffness.

Yeah, that was the plan, I have some aluminum swedge tubes and heim joints I'll use. I'm putting together my own coilover setup so I'll weld the tabs to the strut housing as well.

[jlevie]

For optimal handling spring rates, sway stiffness, and sway bar geometry are all related. Twiddling with one affects the others.

[bmwguy325is]

You can also mount the stock style sway bars on the strut housing using M3 style tabs, which will significantly increase sway bar stiffness.

It changes the way the bar is leveraged. I like the bar hooked to the control arms.
I run IE's largest bars for autoX 25mm/22mm If I recall.

[IronFreak]

I understand this...but I don't. Got anything I can read to learn more about the effects one has on the other? I don't want to just say I have a fancy part, I want to optimize it's ability to make me stick to the ground.

[Nsquared97]

Tune to Win by Carroll Smith.

[R3Z3N]

Obviously going to a larger sway bar is critical for counteracting roll of the vehicle. My questions is....Is there a minimal amount of deflection required in a sway bar, can they be too stiff? They tie one side to the other, but each side still needs to work independently of each other.

I know that most E30's use a solid bar bent to conform around the body, But I have seen other vehicles were clearance wasn't an issue, their aftermarket sways are built from chromoly and other hard, high tensile strength materials that I can't imagine would offer much deflection.

If you STIILLL haven't picked up where I'm going with this....I do a lot of custom fabrication and I was going to take a whack at building my own sways...I did some on my jeep.

Educated input please......GO!

I say if you are going to fab one up, create an in-car adjustable sway bar blade set like so:

[IronFreak]

Wow, thats a pretty sweet design. I was reading about it on their website. it looks like that blase is only on one side of the bar. I'm guessing it eccentric so whem you rotate the blade it adjusts the pre-load on the bar without changing the angle of the drop links or arm length?

It must be to early because I am having a hard time wrapping my head around how thats possibly by only adjusting 1 side.

[jlevie]

As the tapered bar is rotated the force required to deflect it changes. The least force is required when the flats on the bar are horizontal and max when they are vertical. Since the bar across the car is free to rotate preload doesn't change, but the effective stiffness of the sway does.

[IronFreak]

I like this. pretty cool!

[R3Z3N]

I failed. I posted only an adjustable blade type, not adjustable while driving like so: