Go play with the calculator. Increasing bar size .1 inches requires shortening the end length 2 inches to get the same gain! Bar size MOST CERTAINLY is the biggest factor in how stiff the bar is.

edit, here's the numbers I was using

Case 1: lets call this the base number...
A:12 inches
B:36 inches
C:12 inches (since your arm will be at a 90 degree angle to the bar in your "speed bar")
D: 1 inch

386 lb/in
-----------------------------------
Case 2: increase bar size 0.1 inches, others remain the same.
A:12 inches
B:36 inches
C:12 inches
D: 1.1 inch

565 lb/in
-----------------------------------
Case 3: in order to match Case 2's 0.1 increase to the original parameters you have to decrease A and C 2 inches.
A:10 inches
B:36 inches
C:10 inches
D: 1 inch

570 lb/in
-----------------------------------
I'm not trying to back you into a corner, but you really don't seem to know what you're talking about when it comes to sway bar calculations...

 

If I keep the extending arm the same length and the mounting points the same why is that going to drastically change the anti-roll? Its just going to be faster to transfer the load from one side of the other due to less rotational friction from not having poly bushings that run out of grease and suck.

It's going to be very similar to what I have on my car already, I never said I was going to change the over all geometry of the sway bar, I just said I'm going to change the bushings it was mounted in. Then I add multiple points to attatch the endlinks to adjust how stiff the bar is and thats it. Its really as simple as that.

The only way it gets complicated is if you completely re-design the entire thing which I haven't done.

 

Thats why you make multiple endlink mounting points, you can change how stiff you want the bar to act. Also by making the endlinks adjustable themselves you can change the length of the endlinks all you want. I dont need to play with a calculator.

Also if that where true my endlinks would have to me less than an 1" tall right now on my current bar. Guess what they're not. They changed length less than a 1/2" in over all length.

 

Sigh, OK. You're right... calculations are for faggots. Just throw it together, it should work better than whatever those silly engineers at Suspension Techniques or Progress, or even Nissan put together.

This ranks right up there with V-band couplers for intercooler piping... I know you guys all think you know a lot, but you really don't. I'm just using google and trying to present an alternative idea to yours. Keep in mind, I'm not claiming I know a damn thing at all about suspension...but you don't see me trying to fabricate my own sway bars either, do you?

 

I was going to buy the Progress sway bar but for now I put the energy suspension sway bar mount and end link bushing kit on my stock sway bars and I noticed a big difference. My rear wheels like to come up 6+inches around sharp turns. I think that will be fine for now.

 

Here is another point. Do you know how stiff the stock bar is? Do you know how stiff any aftermarket bars are? No? I'm not worried about the exact spring rate of the bar when I have nothing to compare it to. I'm worried about if I like how the car feels after when I drive it. I dont care what the bar rate is if I like the way it feels. What I'm making will not be far off whats already on the car and I dont see the huge issue with it. If I'm using a bar thats almost exactly the same size as whats on it now and going from a poly bushing to a bearing what exactly is going to go wrong?

Does that calculator take in to account how much force you loose when you use rubber bushings or when you use polyurethane bushings? no? You're overly complicating things.

 

You can calculate the stock bar stiffness! I don't care, so I'm not going to do it, but that's something someone who's as serious as you guys about your suspension might want to consider doing. Then you have a number to compare to! You can even calculate your progress bar, and then take all that into account when you design your new bar!

If you're going to go through all the hassle of custom fabricating parts, you might as well do some engineering calculations to support them. It's going to take you very little time on the overall project, and the end result will probably be better than if you just eyeball it...

And the bar calculator is assuming its going on a race/high performance car, so I'm sure it just assumes zero deflection. Poly bushing or spherical bushings should both have zero deflection.

 

I never said I was going to e-ball anything. I just said I wasnt going to use your calculator.

 

I never said you had to use "my" calculator. It was just the first one I found on Google. Who knows if it's the best one out there... I just think you should take into account the different variables. It's not as simple as you're making it out to be. It might not be as complicated as I'm making it out to be either, but it doesn't hurt to at least think about the design a little bit.