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Front sway bar - direct acting vs normal

Posted: Sat Dec 31, 2016 4:47 pm
by heavywoody
First, this isn't for my Beretta, but it does spawn some theory which is why I'm bringing it to the forum.

So, for those of you that don't know, a direct acting sway bar is one that had end links which attach to the strut housing (or a bracket that comes off the strut knuckle bolts). (FE7 on our cars - GTZ's, Indy's, and W26's had this)

What I refer to as a "normal" sway bar is one where the end links bolt through the control arm. (Standard FE1/FE2/FE3/F41 suspension on our cars)

Is there a point based on vehicle weight/weight distribution that the direct acting becomes less effective than a normal bar, or would a direct acting bar always be the more neutral handling choice?

I want less understeer and a more balanced feel. Obviously there are other factors at play here (tire size, strut valving, spring rates, etc.

And yes, this is for my Montana minivan. Don't judge.

Re: Front sway bar - direct acting vs normal

Posted: Mon Jan 02, 2017 9:13 am
by bonecrrusher
Why yall judgin?

I always liked the way my GTZ handled over my GT and Z26 - hell I even swapped that FE7 bar to the Cavalier.

Does it push/pull more in the corners - I couldn't tell you. Just by driving feel it always felt more stable.

I'm sure others will chime in with more technical terms. :p

Re: Front sway bar - direct acting vs normal

Posted: Mon Jan 02, 2017 9:37 am
by woody90gtz
I'm sure at some point a huge traditional bar would be more effective than a small direct bar, but don't know the math to figure out the threshold.

However, neutrality comes from your front/rear balance. If you have understeer now you either want less front bar or more rear bar. I would go more rear.

Re: Front sway bar - direct acting vs normal

Posted: Mon Jan 02, 2017 3:34 pm
by Cliff8928
I have always found that the direct acting bar makes the steering feel much better, probably due to it mounting to the strut which rotates, unlike the control arm. I'm sure there's a point at which the standard bar will be more effective. The direct acting bar is smaller because given the same suspension movement, the mounting point of the direct acting bar will result in it flexing significantly more.

Now just if there was an engineer who could figure out at what point they would exert equal force :P