Whiteline Sway Settings?

[BMR Tech]

I want to run stagger, and all of the aftermarket bars are softer than the Boss and Boss ls bars.
Is there a good reason Ford made those bars so stiff?

Looks like the whiteline rear bar is softer than the stock brembo bar.

The Boss 302 front bar is 34.6mm and the rear is 25mm.

The LS has the same front bar, but a 26mm rear bar.

The rear bars are indeed pretty stiff, in comparison to the typical aftermarket offering. The front, most 3-Way adjustable front aftermarket bars are stiffer in the "stiffest" setting of the 3, than the stock Boss front bar.

 

[BMR Tech]

FWIW, the 2013 GT500 (coupe) also comes with:

34.6mm Front

25mm Rear

 

[zquez]

I want to run stagger, and all of the aftermarket bars are softer than the Boss and Boss ls bars.
Is there a good reason Ford made those bars so stiff?

Looks like the whiteline rear bar is softer than the stock brembo bar.

They made their bars stiff so that they could run their springs soft. When you start adding spring rate, you'll actually want less bar.

 

[BMR Tech]

From my calculations, assuming the 34.6mm bar found on the GT500/Boss is hollow and has a wall thickness of .2165".....the rate is 487lb/in.

I am assuming the torsion bar arm length is 14" (this is pretty close to the factory S197 design)

The rear, at 25mm, on the GT500/Boss should be in the neighborhood of 249lb/in

 

[fun4me]

FRONT:
Strano Performance 35mm hollow: 472, 547, 642 lbs/in
Ford 34mm hollow (2005-2010 GT): 385 lbs/in
Ford 34.6mm hollow (2011+ GT, Brembo, Boss): 436 lbs/in

REAR:
Strano Performance Parts 8419 1" tubular: 162, 185, 225 lbs/in
Ford 20mm Solid (2005-2010 GT): 96 lbs/in
Ford 22mm Solid (2011+ V-6 standard): 147 lbs/in
Ford 24mm Solid (2011+ 5.0, GT500): 193 lbs/in
Ford 25mm Solid (Boss 302): 250 lbs/in
Ford 26mm Solid (Boss 302 Laguna Seca): 275 lbs/in

From one of the above posts....

The rear spring rate is not all that soft from the factory. Brembo is 167lbs, not sure about the Boss and Boss LS. Most guys seem to be running around 200lbs aftermarket.

 

[BMR Tech]

167 is softer than most aftermarket rear springs, but you are right....it is not "too" soft.

I would say a 167lb rear spring would work well with a large diameter, "stiff" rear bar in most handling applications.

fun4me, according to your post about the Boss bars being stiffer, it appears to me that most aftermarket front bars are substantially stiffer than the Boss's....and the Boss rear bars are stiffer than most aftermarket. I'll take it that you were asking about the Boss rear bars.....

 

[Norm Peterson]

I'd be interested in any dimensions as well.


FWIW, it appears that the data provided for the OE bars elsewhere in this thread were calculated using the formula in Fred Puhn's book. Torsion and arm bending are considered. The results may be up to about 5% stiffer than what you might get by considering more deflection effects, but that's close enough for most purposes.

What I'm calculating for the stiffness of Sam's front bar settings is about midway between what you'd calculate using Fred Puhn's formula and what you'd get considering torsion in the lateral portion only. For the rear bar settings I'm consistently getting 20% - 30% softer results with either method. But it's entirely possible that the measurements I made of the bars I got from Sam are a little "off", or that the effective arm lengths of the 25mm bar differ slightly from the 22mm bar that I have.


Norm

 

[BMR Tech]

Norm, for your rear calculations, what are you using for the torsion bar arm length? 10"?

What about overall torsion bar effective length? 46.25"?

I cannot imagine there being a lot of variation there.....but I could be wrong.

For our bar, I use a 10" Arm Length, 46.25" Bar length....and they are 22mm. That puts me about 146lb/in. for our 22mm Rear Bar.

 

[speedfreak1000]

kinda off topic but on topic too.

these just came in today.

 

[BMR Tech]

speadfreak, perfect!

Get me some measurements on those bad boys.

 

[fun4me]

Yeah Kelly, I'm perfectly happy with the rates on most front bars. Its the rears that have me thinking.
From the brembo50 website:
Base GT
34.6 mm24mm123 lbs.156 lbs.
Brembo
34.6 mm24mm131 lbs.167 lbs.
Boss 302
34.6 mm25mm148 lbs.186 lbs.
Laguna Seca34.6 mm26mm137 lbs.191 lbs.

As you can see the Boss and Boss LS have a decently stiff rear spring and a very stiff rear swaybar. Are the Ford engineers on to something?

 

[BMR Tech]

I'd like to know the wall thicknesses they are using on the various versions.

 

[speedfreak1000]

speadfreak, perfect!

Get me some measurements on those bad boys.

if you can walk me through on what you need measured and how you'd like them measured i'd be happy to. also been on the phone with the wife telling her how i need the LCA's and relocation brackets.LOL

 

[BMR Tech]

You basically want to measure the "main" bar length, then the length of the arms on the left and right.

The shape may not be similar, but this is what I am looking for.

 

[fun4me]

I'd like to know the wall thicknesses they are using on the various versions.

I thought the rears were solid?

 

[BMR Tech]

Then I'd like to know what they are doing to have higher rates on the same diameter bar. I find it really hard to believe they are using a different shape bar...

 

[speedfreak1000]

here you go Kelly. if you need different shots or measurements of certain areas just let me know cause they are sitting here in the living room.

front

front bar weight

rear

rear bar weight

 

[Sky Render]

When calculating the Whiteline rear bar's stiffness, remember that it mounts directly to the axle:

 

[fun4me]

Then I'd like to know what they are doing to have higher rates on the same diameter bar. I find it really hard to believe they are using a different shape bar...

24,25,26mm doesnt seem the same.

 

[speedfreak1000]

hey sky render i see you have your in the last hole, is that the softest setting? i just took mine out of the box and havent looked at any of the instructions.