S197 Spring and Sway Bar Rates

[twistedneck]

I'm trying to find replacement front sway bar bushings for a 13 boss 302. It has the 34.6mm bar. All I can find is the 35mm bushings. Anyone know where to find the correct size bushings? Ford discontinued them. All of the aftermarket selection is 35mm.
Thanks.

Edit: Check the old bushings on pre 2010 cars.. looking now there was a 34mm bar back then, meaning that 34mm bushing should fit just fine and its not bonded so rate will be 7% less than the 2010+ bonded ones. But you will also need to get the matching brackets.. the cross section shown is the 2010-2014.. the first gen were slippy and had a different hump.

I'm pretty sure those were bonded on to the bar and they are not for sale without the front bar. The front assembly is made by Mubea, an excellent German company with plants here in the USA. Its not a great design with the open ears on the bracket so the rubber can squirt out and it has hysteresis when the outside of the bonded bushing slides against the inside of the bracket.. we fixed all those issues on S550. Back in 2003 when the S197 was getting designed nobody could do full rubber assemblies with preload and all that to see what was going on. I think in 2010 they started bonding them to stop noise. I remember doing research on this back in 2003 and i was able to pull data from like the 77 Tbird and some other crazy old cars that had noisy bushings, there was no fix at all for 50years! until 2013 when we designed the 2015 S550 setup.. thanks Ansys!

 

[stevbd]

@twistedneck interesting stuff, thank you. On my 2011 GT I’ve removed the oem front bar but I’ve always been interested, how much does the bonding affect rate?

 

[twistedneck]

@twistedneck interesting stuff, thank you. On my 2011 GT I’ve removed the oem front bar but I’ve always been interested, how much does the bonding affect rate?

you are welcome stevbd, bonding is about a 7% rate increase from slippy.. however slippy can wear out the center hole very fast and the bushing rate falls off a cliff.. You are allowed up to 35% rate loss after the full vehicle durability if that tells you anything. Usually you want 20-25% deg max but that's a lot more than 7% bump you get by bonding. The other stange thing about bonding is its called a parasitic rate because its not increasing the effectiveness of the bar its reducing it..example over speed bumps a normal slippy racecar system has no affect but with bonded bushings all of a sudden you are adding the wind up of bushings to spring rate!

 

[N.Panda]

I know I am posting on a very old thread, but does anyone know the part number for that Boss 302s small rear sway bar?
REAR S197 Bars:
Ford 13mm Solid (Boss 302S):............ 18 lbs/in

Or if anyone has leads on it. Playing with suspension and spring rates on our FR500

 

[mwjscn]

Ford 13mm Solid (Boss 302S):............ 18 lbs/in

That's the 1/2" Watson Racing bar. I believe they don't make it any more, but you could call and ask. You could also try putting up a Wanted post in the Marketplace section.

 

[BackInBlack]

Don't know if anyone still maintains this awesome list, but if you do, I think I may have the rate on GT500 springs (2008 model):

Factory Spring Rate(s)? 2007

www.fordgt500.com

Fronts: 195 lb/in, Rears: 167 lb/in

Guy who posted it says that its from the manual supplement.

 

[BackInBlack]

I know I am posting on a very old thread, but does anyone know the part number for that Boss 302s small rear sway bar?
REAR S197 Bars:
Ford 13mm Solid (Boss 302S):............ 18 lbs/in

Or if anyone has leads on it. Playing with suspension and spring rates on our FR500

Dunno if this helps, but the 3V bar was 6R3Z5A772B. There is a Dorman equivalent: https://www.dormanproducts.com/p-49717-927-203.aspx

 

[mwjscn]

Dunno if this helps, but the 3V bar was 6R3Z5A772B. There is a Dorman equivalent: https://www.dormanproducts.com/p-49717-927-203.aspx

927-203 is the 18mm rear swaybar, not the 13mm. It has a 55 lbs/in rate not a 18 lbs/in rate.

 

[BackInBlack]

927-203 is the 18mm rear swaybar, not the 13mm. It has a 55 lbs/in rate not a 18 lbs/in rate.

Yeah that's right. Wasn't thinkin

 

[RodS197]

I have the Watson bar on my car. It is the best. I did consider the Cortex adjustable bar and Philip said the softest setting is the same as the Watson bar.

Won’t help if classing rules won’t allow it, but an option otherwise.

 

[Tim.ocon]

Okay so these are for sale on marketplace but I can’t find ANY information on the drop or spring rates ANYWHERE and the description leaves much to be desired
The only other writing on the springs in the photo is SA 003. FSA

Any insight would be greatly appreciated

 

[mwjscn]

The drop measurements are right on Steeda's website. You can call them for rate information if you want to pursue them, but Steeda suggests they're not for V6 cars due to them having a lower front-end weight (V6 front would ride higher than measured on a GT). According to other Steeda posts, the ultra-lites are physically marked Steeda Superlite SA 003 FSA.

Steeda Ultra-Lite Mustang Lowering Springs (2005-2014)

Springs are the foundation of good handling and ride quality. So start with the best springs for your Mustang, built by the company that specializes the vehicle dynamics and your Mustang!

www.steeda.com

 

[Tim.ocon]

The drop measurements are right on Steeda's website. You can call them for rate information if you want to pursue them, but Steeda suggests they're not for V6 cars due to them having a lower front-end weight (V6 front would ride higher than measured on a GT). According to other Steeda posts, the ultra-lites are physically marked Steeda Superlite SA 003 FSA.

Steeda Ultra-Lite Mustang Lowering Springs (2005-2014)

Springs are the foundation of good handling and ride quality. So start with the best springs for your Mustang, built by the company that specializes the vehicle dynamics and your Mustang!

www.steeda.com

Good to know! Wasn’t aware of the difference in marking

I guess I didn’t look hard enough

 

[Tim.ocon]

The Steeda Boss comp springs I see they use the boss reference. What would the drop be on a v6/gt car.

I’m trying to sort out weather to get the Steeda boss springs or the Ford KA springs as I may have found a used set of ford springs for a great price

 

[ShifterX]

The Steeda Boss comp springs I see they use the boss reference. What would the drop be on a v6/gt car.

I’m trying to sort out weather to get the Steeda boss springs or the Ford KA springs as I may have found a used set of ford springs for a great price

Not sure on the V6, but on my GT the front drop was about .5”- .75”. ended up around 15.25” hub to fender. I am selling my Steeda boss springs. PM me if you are interested and I will get you all the details.

 

[Tim.ocon]

Not sure on the V6, but on my GT the front drop was about .5”- .75”. ended up around 15.25” hub to fender. I am selling my Steeda boss springs. PM me if you are interested and I will get you all the details.

Do you know what the rear drop difference is. Where are you located?

 

[ShifterX]

Drop was about 1.5” in the rear on my GT. 15.25” hub to fender. I am in CT

 

[Alatalo]

S197 Springs Front/Rear:
OEM:
Boss 302 ................... 148F/186R lbs/in
Boss 302 Laguna Seca 137F/191R lbs/in
Brembo GT/ GTPP ...... 131F/167R lbs/in
GT and V6PP............... 123F/156R lbs/in

This thread is very informative and I am waking it up again since I am trying to perform some calculations on my car.

Does anybody remember where the above quoted OEM spring rate measurements came from..? Are they all linear springs and / or measured at the approximate ride height of the car...?

Also, the numbers 136 lbs/inch (front) and 142 lbs/inch (rear) are frequently mentioned on several Mustang forums regarding 2005-2009 S197 coupes. Does anybody know where these numbers came from and likewise if they are linear or at least measured at the ride height of the car...?

Furthermore, a number of quotes from older threads on several Mustang forums suggest 2005-2009 S197 coupes could have been assembled with any of six different OEM front springs and six different OEM rear springs. Supposedly all with the same spring rates, but with small differences in free length, likely to put cars with different level options and thereby weight to the same ride height and thereby geometry. Does anybody know if the OEM spring rate and free length information is available somewhere from Ford...? I would like to believe so since one specific post (in an old thread about the first ever Cobra Jet springs) has this information for two of the springs only, like the information was copied straight out of some kind of database with much more information than today's spare parts fiches.

 

[Fabman]

This thread is very informative and I am waking it up again since I am trying to perform some calculations on my car.

Does anybody remember where the above quoted OEM spring rate measurements came from..? Are they all linear springs and / or measured at the approximate ride height of the car...?

Also, the numbers 136 lbs/inch (front) and 142 lbs/inch (rear) are frequently mentioned on several Mustang forums regarding 2005-2009 S197 coupes. Does anybody know where these numbers came from and likewise if they are linear or at least measured at the ride height of the car...?

Furthermore, a number of quotes from older threads on several Mustang forums suggest 2005-2009 S197 coupes could have been assembled with any of six different OEM front springs and six different OEM rear springs. Supposedly all with the same spring rates, but with small differences in free length, likely to put cars with different level options and thereby weight to the same ride height and thereby geometry. Does anybody know if the OEM spring rate and free length information is available somewhere from Ford...? I would like to believe so since one specific post (in an old thread about the first ever Cobra Jet springs) has this information for two of the springs only, like the information was copied straight out of some kind of database with much more information than today's spare parts fiches.

what are we trying to do?

 

[Alatalo]

what are we trying to do?

I am performing the most basic calculations just to see what I have got from a wheel stroke and wheel rate point of view. I then want to check the effect some of the popular aftermarket options offer. Just to improve my own understanding regarding what I have got and what direction various aftermarket options will take me.

The old post on the S197 forum that I am referring to says the following:

I found this:

5R33-5560-BC: rear spring, standard, GT
rate: 24.9 N/mm, free ht: 361 mm, tag: blue

5R33-5560-AC: rear spring, special, Bullitt Mustang
rate: 24.9 N/mm, free ht: 355 mm, tag: light blue

same spring rate but just a tad shorter

Unfortunately, posted by a member that has not been active since 2018. Still, it indicates there is collected spring rate and free length information for the OEM springs, somewhere out there. This is not from the workshop manual and this is also not the information available in the normal spare parts fiches. So if somebody knows where to find this information, I am all ears.