[QUOTE]Originally posted by jzr
[B]And I think I found out why my car's been so peppy lately.

 

Looks like crushed can of Red Bull.....................

 

Ding ding ding Mack gets the prize!


I have no idea how it could've gotten in there....

 

I've heard the engine in the s2000's referred to as "squirrels on crack" Maybe yours is "squirrels on Red Bull"?

Same end result.

 

If anyone is looking to replace their Mugen or Gendron bar with the Comptech, I'd be interested in buying your old bar. Just can't justify a Comptech unless this GB gets the price closer to $600.

PM or email me.

Thanks!

 

The pictures have convinced me that this is a good mod for red (brackets) or silver (bar) cars. $600 or so for this bar might be hard to find this spring, but I found a dealer selling them for $675.

 

I've got a Matcad document setup to calculate the spring rate of this unique anti-roll bar, but I need to get some more dimensions to better dial in the calculations. The result of the calculation is fairly sensitive to these parameters:

1st - I need a dimension from the center of the left side bend to the center of the nearest screw hole (I belive you guys with the bar call it the #5 hole). By center of the bend, I mean the point you would find if you drew an imaginary line down the axis of rotation of the bar and intersected it with a line down the center of the bar's lever arm. Hopefully that sounds more clear to you than it does to me.

2nd - The distance from the center of the weld on the right side to the center of the right side bend. Same definition for center of the bend applies

3rd - I need the lever arm perpendicular distance. By this, I mean that if you were to extend the axis of rotation of the bar outward, and then drew a line perpendicular to this axis, what would be the shortest distance possible to the end link attachment hole? In the past, I've made this measurement by laying the bar down on top of a large, carpenter's box square. I lay everything out on the ground, and then line the rotation axis up with one edge of the square, looking straight down. Move the bar around until the drop link hole lines up with a perpendicular edge of the square. Read the dimension off the square and you've got the perpendicular distance.

Yeah, it is a bit of work to get these numbers accurately. However, I'd be more than willing to share my equations and results with the group once they are dialed in with correct numbers.

 

Steve, why don't you just measure your own bar? Unless you don't have one?

The measurements I listed in the picture in this thread were taken in the method you describe, albeit with not-so-accurate instrumentation (tape measure). I doubt you're going to get anybody to spend an hour or more measuring their bar to come up with anything more accurate. Not to mention the bar in action is a dynamic situation and we're forgetting endlink flex and a host of other things, so your conclusion on bolt loads (at least in my mind) will still be inconclusive.

Don't take this the wrong way, but I don't understand the crusade to prove this thing will break. It's your right to do so, but I think the community would be better served were your talents focused on something like why our a-arm brackets have been tearing off. That has already happened to 3 people I know, with no agreed-upon causation; I've yet to see any broken swaybar bolts.

As the only person who had the "knock" that's taken their bar apart to see what it was, I also think the severity of this is being greatly overplayed. The bar knocked from day one and it didn't get noticably worse over the life of the unit. Until the first bolt breaks why not accept it as a character trait of the bar and move on?

But if we must analyze it to death, Andy and I would appreciate it if you could tell us the % increase in stiffness when adding a bolt to the full-soft bolt hole when there is already a bolt in the full-stiff slot. Comptech told him it was like 1%, while my rough estimates came out closer to 20%. Who's closer?

Have fun!

 

I don't have a Comptech bar, I'm running a modified Gendron bar on my car. Believe me, this thing has got issues too. Nothing seems to be nirvana in aftermarket bars.

Don't get me wrong here, I'm not on a crusade to prove it will break. I'm an engineer that enjoys a challenge, and here the challenge is to create a reasonable calculation to find out what the loads on the screws are, with a minimum of data. I'm just trying to be helpful, and normally have very little time to do these sort of things, but I'm making time in this case to help out other S2k auto-xers. I've already invested way more than one hour putting the equations together to calculate the rates. I could have gone home at 8 last night, but instead stayed until 10 working on this (yeah, I'm a geek w/ no life).

My other motivation is to figure out what kind of spring rates this bar is capable of. I'm curious how it compares with my bar's settings, and if we are all homing in on the same rates with our various different bars.

As for a-arm brackets, it doesn't do me any good to try to figure that out. Something is simply underdesigned for the loads (my guess is side impact loads from racing on bumpy surfaces), and it is going to eventually fail. There is nothing we can do to fix it in stock class, other than watch carefully for cracks.

That said, I asked for the dimensions because, from the pictures, the length from the outer holes to the bends looked way too big, but pictures can be deceiving. However, I still need a dimension to the weld. I guess a distance from hole #1 to the weld would be easiest.

I wanted to get things a bit more accurate before I start tossing numbers out. People always remember the first number you toss out, even if it is wrong.

BTW - I'm an engineer, and it's my job to analyze things to death! Just wait until I get going on my exhaust (hope to run the Veilside & stock across the flowbench at work before this weekend).

Steve