Klunk explained

[scott42]

Newfs correct, though, "What if" is the biggest part of that equation...actually "when" is a big part of it too. Mazda has shot themselves in the foot by trying to take short cuts. I'm sure it would have been much less expensive for them to follow the original RB specs when it was realized that their cost cutting design didn't work. We already know this, but I felt the need to vent.

 

[changedman]

wow. interesting. I WANT A FIX!! keep us updated! (thumb)

 

[YuYuRena]

No offense guys, but I tried to understand your statement and now I'm getting confused. And I'm not an expert on English so pardon my rude question, but can you draw the problem and specifically tell me what's all these thing? I've looked underneath my car. followed the mp3 thread about the clunk for since feb (i was a lurker back then). I can kinda picture the design, but I'm a visual learner and I would like to see what you're talking about in a more "visual" format. Thanks.

And before flaming me, I've seen the pics of RB design with the bracket, but I can't see the differences between that and our cars+mp3. I'm a thermo guy, took the required classes in mechanics but I like and know thermo and aerodynamic better.

 

[Newf]

yup, and scott is right too.

No one knows if the racing beat setup wouldn't clunk or not. So it's just speculation at this point. The Racing beat car is rarely driven, and it's driving on smooth Californian roads in the ideal climate. So does it work as a daily driver? in not so perfect climates? dunno

 

[Newf]

YuYuRena

basically, the bushings are taking on more preassure and weight then they should be, and this causes them to wear faster. Bushings are not meant to take the weight of the car all the time, and it seems that's what's going on. Or at least this is the "theory" as it has never been proven otherwise.

EVerything else is just techno babble

 

[changedman]

welp, it hit 29 this morning here :mad:
now i have the metal on metal 'squeek' and the CLUNK worse than ever ! DAMMIT :mad:

 

[Pmpkinhead]

What would be the standard warranty on such an aftermarket item. There is a LOT of EASY money here but if there is a miserable failure the forum will go nuts!!!
1244 (msporange

 

[changedman]

thats true, you have to make sure, ESP and aftermarket 'fix' WONT develop the problem. i think it would make a company go under. esp a little one...

 

[ping]

YuYuRena: Easy way to picture this: Take an old pen and extend the pocket clip out at 90 degrees, perpendicular to the pen in an "L" shape. Hold the pen in the middle, then push down on the end of the clip. See how the pen wants to both rotate AND pivot downward? Now hold the pen right at the clip, and again push down on the clip. See how the pen only wants to rotate now?

The idea (it's a perfect solution BTW) is to only have the anti-sway bar ROTATE in the bushings, rather than flexing and rotating. Flexing and rotating causes problems even beyond busing wear when the bodyshell is subject to odd stresses (forces other than simple push-pull).

If that part pictured is for a Protege and in manufacturing ANYWHERE, I'll buy a pair.

Good call, Micaspeed!

 

[scott42]

that's great a great visual representation Ping...cheers to you!

Micaspeed, if able to produce a quality fix, would become a living legend

 

[DooMer_MP3]

Wow, awesome explanation ping. Makes much more sense to me now! .

Chris

 

[Newf]

if you read the clunk thread in the mp3 section, one of the solutions that Mazda engineers were going to try was exactly what ping is saying. It is my understanding that this techique is used in many race applications. It provides a harsher ride, but last longer.

Good explanation too dood!

 

[1sty]

yup, and scott is right too.

No one knows if the racing beat setup wouldn't clunk or not. So it's just speculation at this point. The Racing beat car is rarely driven, and it's driving on smooth Californian roads in the ideal climate. So does it work as a daily driver? in not so perfect climates? dunno

So tell racing beat to send me their ends, bar, brackets and bushings and I will beat the hell out of them up here all winter.

 

[YuYuRena]

Ok, I thanks for the information and visualization. I'll play around with it, but it sounds like from your explanation, it's a force-coupling issue (shear center and bending-torsion force). I'm probably repeating information, but this is what first glance at it sounds like. Basically we need to decouple the forces and apply the load at the shear center? I'm guessing that's what Micaspeed wants to accomplish.

And thanks again ping. Maybe with this I draw up a force diagram or something.

 

[ping]

Cool - glad the "visual" worked! Now to find me a welder with a little sense of adventure... maybe I can even get them to fab me up a saxay grille bar to mount 4 big-a rally lights...

 

[FrozenMazda]

YuYu,

You an engineer?

 

[Micaspeed!]

Great replies! My goal first is to do a prototype, test on my car ,then refine it for production. Initially I will actually do a billet alum, non welded piece and evaluate costs. I do solid modeling, FEA , cnc programing. etc. Tonight I will obtain the critical dims and begin working things out.

If any of you have done this before, you know it takes time. I will not let out a poorly made product. If positioned correctly, a polyurethane bushing could work fine, many cars use these. For the race bar kit, (three piece bar with splined clamp on arms) I will do a flange bearing specifically designed for the bar, no clamp type bushing. Bar will be hollow. Since it is a three piece bar, the splined end will simply insert into the polymer flange bearing.

For people using the stock bar, I will do a billet alum. cnc machined (not welded steel) support bracket which will accomidate a typical clamp type bushing. all kits will be supplied with the billet end links as shown elsewhere.

First kit will probably be for the stock bar setup. Nothing will be sold untill I am thouroughly pleased and the design meets the original intent. When I have a rough solid model, I can post it for you to see. From that, it is off to the cnc shop for a prototype. So it is going to be a while, but I will do it.

Thanks for the interest and encouragement!

Godspeed!
Dave
www.delsingmotorsport.com

 

[scott42]

**choirs of angels sing**


Dave, best of luck with this mission. We can't wait to see what you come up with. Just one suggestion, you should find someone up north or way up north to do some testing as well. It has seemed like the colder temperatures have accelerated wear according to how cold/wet it is. Then again, I can almost guarantee that you are much smarter than I and I'll bite if you think that temperature shouldn't matter should the design be correct. Best of luck; and I'm sure that anyone on here will be more than happy to supply information (like you need it) about any past experiences and "tests" from over the past couple of years.

Oh yeah, and please remember when pricing, that you're dealing with Mazda budgets and not BMW/Benz (2thumbs)

Scott

 

[Mazdaspd035]

Ok, here is my take on the "Klunk". I will try and be short and to the point. The bar is mounted by the two U clamps which house the rubber sway bar bushings. Notice the wall thickness of these bushings. Quite thick for the diameter bar. Most bars have their bushings mounted close to the transition from the transverse portion of the bar where it transitions/bends to the lever portion leading to the strut. In the case of the Mazdaspeed, there is quite a distance from the actual bend of the torsion part of the bar and the lever part to the bushing. Properly designed, the bushing should only see rotation with little axial load. Look under all the Speed Vision Proteges, and you will see the bushing right at the lever arm. This requires major modification.
Two things are happening, when the lever attempts to apply a torsional load to the transverse portion, a bending moment is introduced because the bushing mount is so far from the lever. Now with a thick wall bushing, the bushing is trying to resist the bending moment, it begins to plastically deform and over repeated cycles, the hole gets larger. The increased diameter allows movement in all planes, causing the Klunk. By the way, it decreases it's effectiveness as yuo might imagine.
Time permitting, I am designing both a fix and a modified race type bar.

Godspeed!
Dave
www.delsingmotorsport.com

(bowdown) (drinks)

 

[Allen]

Good information all around, thanks guys. Keeping my fingers cross in light that something positive turns up to eliminate our (guns) CLANKITY KLUNK, SQUEAK SQUEAK!!!!!!!