Engineering a sway bar

[fryerfighter94]

And this is for a class for mechanical engineering? Interested in taking same major, getting emails from colleges already. Mind if I ask about the classes and what kind of stuff you do, and how its applicable (i.e. where do you plan to use your engineering, motorsports, you mentioned suspension analysis). Cool project good work on it too!

[TwoJ's]

I remembered that I had some pictures from an abandoned design for the bar ends. A while ago I was waiting on my material to arrive, so I went to the machine shop and made up some bar ends that I intended on using.

There just happened to be some 1" 4130 bar at the lab that was to be used for Jominy tests for the metallurgy course. I turned down a .5" length, .750 diameter section that would be fitting inside the sway bar.



I then had to take it over to the mill. I wanted the thinner portion to be cut with a relatively tight tolerance so I chucked it in this indexer. I used a dial indicator to ensure I had everything mounted properly and made the cut on one side. Without annealing, 4130 is not the best material to machine, so I was only taking .010" off on each cut. That wasn't bad, just made it monotonous. After making the first cut I just rotated the indexer 180 degrees, set the table accordingly and went for it on the other side.





I then rotated it 90 degrees and made the hole.



In the end, it looked good enough, but I wasn't satisfied. With this design the part that the links would bolt to is parallel with the bar and I had intended to change the geometry of the bar to accommodate. This design was also flawed because I did not leave enough of a radius for the adjustable links that I will be making to sit flush. I have since changed my design and as you can already tell, I am keeping the stock geometry. Next week I will make the ends.

[TwoJ's]

why not make a sliding mount for the ends so you can adjust the stiffness? (AKA GC's solution)
You could sell a ton of front swaybars with that configuration.

Now that I get to thinking about this, I am not sure that I have seen GC's version of the adjustable sway bar. Do you have a link or a picture that will show the "sliding mount"? I have seen some like IE's adjustable sway bar that simply has three holes in it, but this is not a desirable solution and is just an easy way out. I would be interested in seeing what this sliding mount is that you're talking about.

I think that if I were to go this route, I would not want any moving parts on the bar itself.

Edit: I google'd and found something that may be what you're talking about. I know this isn't the right bar, but is this similar to what you are talking about?

[Aptyp]

awesome project

[Omaliyo]

First off awesome out on the project!

Are you getting your BS or MS in mechanical engineering?

I'll be going to FSU to get my BS in ME..... Can't wait to be designing projects like this..... Love all the calculations and time that goes into things like that...

Your draft of the parts is completely diff from how im learning how to draw lol (measurement layout wise)

[Jesse30]

sliding mount could be accomplished much easier by using a clamping design on the bar itself. rather than having to make all new ends for it. :)

[StereoInstaller1]

Not that I know dick about your school shit, but it seems you could thread the inside of that tube and make the ends thread in, like a tie rod end.

[learningcurve86]

Thank you. Where are you getting these numbers? I'm not denying anything, just curious. The TTT's, and input from a number of sources would disagree with you. There is definitely a stress concentration like I stated in the OP, but I believe that stress-relieving with an oxy-acetylene torch will be sufficient.

I had to do a lab last semester on some material properties, 4130 was one of them. In any case, I think I misunderstood briefly scanning the page (i like looking at pictures, i admit it lol). But in any event, regarding the bar itself, great idea to stress-relieve...

Not that I know dick about your school shit, but it seems you could thread the inside of that tube and make the ends thread in, like a tie rod end.

To add to this idea, and for other suspension tube related projects (camber adjusters, endlinks, etc...)

(rod ends, heim joins, pillowballs)

http://www.pitstopusa.com/Categories.aspx?ID=3380

(threaded suspension tubes)

http://www.pitstopusa.com/Categories.aspx?ID=3381

[mojorising]

Great project. Its great to see a well thought out project like this with engineering actually involved instead of just imagineering. Maybe I missed it somewhere but are you going for a stock rate or did you change it? Also, do you have any test in mind to test the sway bar rate once you get it done? How will this sway bar affect your vehicle roll rate and distribution? One more thought on those rod end mounts: double shear.

[StereoInstaller1]

Hey, that is cool! A heim joint stuck on the end of a sway bar means LOTS of choices in how you could make the end link!

[TwoJ's]

First off awesome out on the project!

Are you getting your BS or MS in mechanical engineering?

I'll be going to FSU to get my BS in ME..... Can't wait to be designing projects like this..... Love all the calculations and time that goes into things like that...

Your draft of the parts is completely diff from how im learning how to draw lol (measurement layout wise)

Yeah, I think I said in there somewhere that the dimensions needed to be fixed. I just threw them on there and printed off a copy to take down to the machine shop with me.

sliding mount could be accomplished much easier by using a clamping design on the bar itself. rather than having to make all new ends for it. :)

Interesting idea, but I doubt it would work out too well. There needs to be a flat surface to bolt to, and the wall thickness is only .120. It's not like making some kind of ends will be hard.

Not that I know dick about your school shit, but it seems you could thread the inside of that tube and make the ends thread in, like a tie rod end.

This is an interesting idea. But I really think that it is just easier to weld them in there. No bull shit cutting threads on the lathe.

And this is for a class for mechanical engineering? Interested in taking same major, getting emails from colleges already. Mind if I ask about the classes and what kind of stuff you do, and how its applicable (i.e. where do you plan to use your engineering, motorsports, you mentioned suspension analysis). Cool project good work on it too!

That's cool man. I would say that you'd be good for a ME program if you like math and physics. That is just about all there is to it. I am getting a math degree at the same time, so math comes easily to me. Don't get me wrong though, there are definitely people in my program that are not great at math, but they just have to try harder at some things. No biggie.

A BS in Mechanical engineering is actually a pretty broad degree. It covers anything from HVAC design to aerospace engineering. I specifically would love to design suspension systems. I think I would like going to work if I had that job. I've also always had an interest in aerospace, so I would love to work for Boeing for 5 or so years. Basically you can do a ton of jobs with an ME degree -- you just may have to learn a few more things once you realize what you will be specializing in.

[87-325ic]

sweet work!! Just goes to show that anything is possible if you want to do it.

[LivingLegend06]

Not that I know dick about your school shit, but it seems you could thread the inside of that tube and make the ends thread in, like a tie rod end.

It's best to avoid putting threads in bending.

I'm curious to see what kind of calculations you did to determine the roll rates and weight transfer.

[Skafrog]

Now that I get to thinking about this, I am not sure that I have seen GC's version of the adjustable sway bar. Do you have a link or a picture that will show the "sliding mount"? I have seen some like IE's adjustable sway bar that simply has three holes in it, but this is not a desirable solution and is just an easy way out. I would be interested in seeing what this sliding mount is that you're talking about.

I quoted this response, but your points are valid on your previous post about selling them. However, if you do decide to market a bar with a sliding adjustment, I would be interested.
In regards to the swaybar mounts, this is ground control's e46 m3 swaybar setup. As far as I know, no one makes a kit such as this for e30's. Obviously, one would need to convert to m3 style swaybar links.

[george graves]

This is my new favorite thread - got to come back when I have time for re-read - interesting stuff.

TwoJ's - is that U-dub?