i just traded my progress for a stillen and i was just wondering if what i'm thinking is correct.

i think that for the softer setting the bar should be in the forward position (aft holes) and the stiffer setting the bar should be in the aft position (forward holes). I'm also thinking on the softer setting the bar should be right under the rear beam/axle and the stiffer setting the bar should be positioned aft of the rear beam/axle to increase the leverage of the bar or decrease the leverage of twist the trailing arms put on the bar.

does that sound right?

 

I think you have it reversed...not sure...I have the stillen one as well and have been contemplating this...I think the bar needs to be farthest forward toward the center of the car before the beam for the stiffest and rear of the beam for the softest...and right under the beam being neutral...

does anyone know this fer sher?

 

I'm gonna link this in the suspension/brakes forum so it gets more responses...

 

Moving the brackets farther apart will result in higher roll resistance.

Moving the bar forward but keeping the brackets at their original position will also result in higher roll resistance.

Moving the bar with the brackets should not make any difference.

At least that's how I understand it.

 

The Stillen bar doesn't have the U-brackets if that's what you're talking about.

On the stillen, the farther forward you move it, the more roll resistance is provided. Ideally, you should have the bar directly underneath the beam axle, otherwise you can have clearance issues with the panhard(ish) assembly.

 

no I'm talking about trailing arm brackets. I'm not sure if you can move them, but if you can, that's probably the most affective way to adjust the stiffness.
that's kinda what I've been trying to say... (second line)

 

i heard this as well...further forward = more oversteer...further away = more understeer....righ in the middle = neutral!

 

didn't they change the layout of the panhard between 00 and 01? before or after the beam...so I guess it depends on which one you have and if it will have clearance issues...

 

i'll be honest, i'm not sure how moving it forward would be stiffer than moving aft. the brackets seem as though there position about the middle of the trailing arms when positioned directly under the beam. theoretically that should be the stiffest setting because it's in the middle of the biggest flex point. one of you mentioned using the holes furthest away from each other. that makes more sense to me than moving it forward. i think i'll try exaggerating both positions to see what my results are. i'll keep you guys posted. anybody talk to Cheston? he's an engineer or something crazy. i bet he would know.

 

the reason it doesn't make sense to me to put the bar forward versus aft is this. i'm sure most of you guys have used a torque wrench before. we all know when we use a torque wrench we should grip the wrench by the handle grip versus the shaft of the torque wrench. reason being is that you have more leverage at the handle, or farther away from the pivot point, then you do at the head of the wrench. kinda like using a 3/8ths drive rachet on a really tight bolt versus using a 1/4 drive. the reason the 3/8ths drive is easier is because it has a longer handle which in turn gives you more leverage.

now lets say you're torquing some thing that needs to be supported at the other end to keep the bolt from spinning, like torquing a nut on a bolt that goes through sheet metal. if you try torquing the nut with out supporting the head of the bolt the whole setup is going to spin. so lets say you're torquing a high value, we'll say 500 ft lbs. you wouldn't grab a six inch wrench to support the head side because it would be a muthafer to keep it from spinning. you'd use a big **** wrench to go along with your big **** torque wrench.

now imagine the load of the torque wrench being deflection in the trailing arms from being loaded while in a turn. now imagine the rsb as the back up wrench. the closer to the pivot point, trailing arm to frame, the lesser the amount of leverage your rsb will be able to apply, like the little wrench.

now the further away from the pivot point the more leverage is added and that's why i think the bar needs to be moved to the rear to be stiffer.

 

No.

The shorter arm on both ends of the bar transmits more movement (or twist) into the bar than a longer arm would.

Imagine moving (your example) the long torque wrench's handle 2". The rotary motion caused would be less than moving the end of the shorter 1/4" drive wratchet by 2". The total circular motion imparted to the bar is what causes resistance, thus the further from the centerline of that torque the attachment point is, the less roll resistance the bar gives.

Buck

 

i'm not exactly sure what you mean

 

Ok.

First, Torsion is the term used to describe what happens when the bar is twisted. Torsion is the result of how much linear distance the ends of the bar move in opposite directions. (One wheel up, the other down) The greater the torsion, the more force that the bar puts on the attachment points, resisting that motion.

My example was unclear. Here is a different one.

Imagine that you and a friend have your strut bar lying on the garage floor with a 8ft 2x4 firmly fastened to each end. Each of you is like the rear suspension of your car. You push the end of your 2x4 up 2" and your friend pushes his end down 2", twisting the bar as if your car was under body roll. The total of 4" travel results in a small amount of torsion or twisting of the bar because you and your friend are so far away from the bar. (1.19 degrees of rotation each side)

Now, assuming you and your friend are pretty damn strong, lets say you and he each grab the actual ends of the bar and you move your end up 2" and he pushes his 2x4 end down 2". It will take MUCH more force to twist the bar. Assuming that the ends of the bar are 4" in length (instead of 8ft), each end of the bar is rotated over 26 degrees!

I hope that is a little more clear.

Buck

 

Agreed. I've always understood moving fore of the beam to stiffen, and rearwards to loosen. In real world testing though I couldn't tell the difference between fore and directly under the beam as too many other variables were also at play.

Of course there's also more radical setups like boxing the beam or this one...

 

That's your setup, Brian? The triple-RSB (Stillen, stock, and the other one..)?

 

IIRC, that was the change they made from the 4th to the 5th gen... 4th gen had it before, 5th gen had it after.

 

oh right, I remember now...it was supposed to better the geometry of the panhard in it's motion curve...

 

No, that pic was somebody's B15 I found. Interesting concept combining a Stillen and Nismo though.

As for the A32 vs A33 panhard location I don't know how they could improve much. My A32 rear has plenty (read too much) of camber grip already. Designing even more grip is just nutty.

 

From http://home.earthlink.net/~maxfaq/history.htm:

 

well, right now i have it as far back as possible. there's an on ramp that i think will serve as a good road test. after i find the limit of the car (or close to) i'll move the bar as forward as possible and test the handling at the same location again. i'll post results by the end of the week.

 

After all the theoreticals have been argued out, I predict little/no perceivable seat-of-the-pants difference in real world driving.

 

yes, but we are looking for at the limit behavior (in which case many times, even finite changes such as tire pressures can have a profound impact on handling characteristics) and perhaps improvements in rear rotation as a result...I have never personally adjusted my stillen rsb but I know people with other cars that have aftermarket adjustable sway bars and they notice a marked difference when they adjust it from one extreme to the next on a typical autoX course

 

hmm...so they did it essentially to reduce snap oversteer.

 

from my understanding yes...

 

i now have the bar in the farthest forward position possible on a 4th gen (5th gens may be able to get it even further forward). already i'm noticing quicker steering but there is one turn in particular that i took with the bar in the previous position that i'm planning on taking this weekend. its a turn that most any autoX events would have. at first i wanted to compare the two positions by taking a highway on ramp at crazy speeds but i was never able to hit the limit of the vehicle. after having ridiculous amounts of grip at about 50-60 mph around a banked on ramp, i decided that that wasn't gonna be a place to "safely" find the limit of my car. i found a flat 30-40 mph left hander that my car has to be babied into, otherwise i'll have understeer for days.

i hit this turn last weekend with the bar far back and my inside rear felt like it lifted alot (more than usuall). i'll hit the turn this weekend with the bar forward to see if i notice a difference.

 

it's confirmed. with the bar in the most forward position the car feels most planted. i still can't get the car to rotate but i think it's cause i'm on the street. once i hit the next autoX i'm sure it'll be a different story.

 

what tire pressures are you running? I always run 35f/37r on the street for more rotation

 

Wanna bet?

 

if you want your car to come out with the bar all the way forward, just "faint" it--slalom...but you better be ready with some serious opposite lock!

 

Scandinavian flick > *

And the opposite lock comment.

 

i don't pay too much attention to pressures on the street.

as far as rotation, i don't really want it, especially on the strret. but with the bar in its current position, i was expecting it. so it did surprise me some to find that i could "not" get it to rotate.

EDIT

 

rotation in a constant-radius turn is more dependent on tire grip than on RSB settings, in my opinion. Want to rotate the rears? jack up the pressure. The RSB adjustments are going to have a more noticeable effect in the slaloms and switchbacks, where the oversteer created (bar farthest back) will reduce opposite-lock issues. In autocross, understeer is the enemy!

Just my perception of what I felt with my RSB adjustments vs. tire pressure adjustments.

 

and on initial turn in which is where most of our understeer begins if you "overcook" it...

 

thanks for all the info fellas