Another Sway Bar compilation, reconciling the data

[NightmareMoon]

With Steeda magneride sport lowering springs, Steeda camber plates , Steeda roll center/ bump steer correction kit, it feels pretty neutral on the track, no under steer and the rear is not loose. My effort here is to keep that balance with a bit less body roll.

Roger that.

Couple things.

So multiple sources report the PP2 rear bar is solid, not hollow, so that's why its as stiff as it is. Other wise we couldn't explain that jump in rate with only <2mm jump in diameter. GT350 bars are same diameter, but hollow, so less rate. They're not the same bar, only the same outside diameter. (Also somebody bought one and verified is a brick and obviously solid)

Steeda makes a couple different swaybars for both front and rear, but I'd take a good hard look at their 'competition' rear... its less rate than the BMR or Steeda's normal rear swaybars and should pair well with a BMR front bar and allow you to get very close to your current balance, but slightly on the understeer side, but I think a healthy amount.

Honestly the PP2 rear bar appears surprisingly stiff. (for a stock bar)

Know that you can set one side of a bar on one setting and the other side on a different setting to get a more adjustment out of a bar, no it doesn't cause asymmetrical load, its an old racer trick.

What front and rear camber are you running? that also makes a difference in balance.

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[GTP]

Most people arent able to drive an oversteering car and can’t gain time in the corner entry phase, so they double down on getting traction on corner exit.

i’ve done rear-bar only and front bar only setups in the past. They were different but ‘about the same’ in autox lap times once you mastered how to drive the setups. Both bars is superior, but you dont necessarily want a rear bar as stiff as some companies sell. (It depends). FWIW my front bar is never set on full-stiff.

How did you evaluate your bar changes - feel, lap time, ...? And do you mainly AutoX or track?

 

[NightmareMoon]

How did you evaluate your bar changes - feel, lap time, ...? And do you mainly AutoX or track?

my final bar changes on my own car were through experimentation, but I also have looked at bar dimensions quite a bit as well. I’ve dialed in swaybar and shock setups for stock PP1 springs, steeda competition springs, and for much stiffer track springs. I current run a 650 front spring and aero, but the journey has been long. I’ve gone through like 12 sets of autox/track tires on this vin number.

I primarily autocross, I instruct autocrossers, I’ve won Top PAX at local events many times, and won CAMC at Solo Nationals in 2022. Last year I was invited to demo a Mach 1 for various Shelby and Mach 1 drivers and passengers as an exhibition at a Shelby event.

I also have a number of track days and have always done both. For a while I had a ‘membership’ at a local track and would test and play on track over lunch breaks on a regular basis, and this was were I was able to do a lot of setup tuning. I’ve done most of the texas tracks and am local to CotA. Im not as experienced as somebody like Honeybadger at CotA but my lap times are respectible. I’m very used to driving a mustang with slip angle and throttle steer, etc.

 

[GTP]

The difficulty as I see it is that it would require an open track day to make and evaluate performance changes.

• Traffic is much lower.
• No session start times pressure.
• Work up to a good, fast, consistent lap time.
• Change bar.
• Go back out
• Compare times.

Not a trivial undertaking.

Or, I could have a Mustang- specific instructor drive my car and report. But I get too nauseous within 3 laps.

 

[Bossdog]

Roger rhat

Steeda makes a couple different swaybars for both front and rear, but I'd take a good hard look at their 'competition' rear... its less rate than the BMR or Steeda's normal rear swaybars and should pair well with a BMR front bar and allow you to get very close to your current balance, but slightly on the understeer side, but I think a healthy amount.

Honestly the PP2 rear bar appears surprisingly stiff. (for a stock bar)

What front and rear camber are you running? that also makes a difference in balance.

The Steeda competition bar is soft, for use with stiff springs, I have soft springs. I don’t see how moving to a softer bar will move me toward my goal of less body roll. Less rear bar also increases understeer, again opposite of my ultimate goal of maintaining current PP2 stiffness ratio, front to rear.
I think the standard Steeda bars, Steeda part #’s 555-1015 and 1016 will accomplish my goals.

 

[Bossdog]

The difficulty as I see it is that it would require an open track day to make and evaluate performance changes.

• Traffic is much lower.
• No session start times pressure.
• Work up to a good, fast, consistent lap time.
• Change bar.
• Go back out
• Compare times.

Not a trivial undertaking.

Or, I could have a Mustang- specific instructor drive my car and report. But I get too nauseous within 3 laps.

I'm the exact same way, 3 laps as a passenger and I’m DONE!

I think the standard Steeda bars with front, Hole 2and rear, hole 3 has enough testing from Steeda and field use, I’m comfortable taking it to the track. It may not be perfect, but I don’t think it will disrupt a track weekend, with unsafe or unusable results at the limit. I can adjust from there if need be.

 

[NightmareMoon]

The difficulty as I see it is that it would require an open track day to make and evaluate performance changes.

• Traffic is much lower.
• No session start times pressure.
• Work up to a good, fast, consistent lap time.
• Change bar.
• Go back out
• Compare times.

Not a trivial undertaking.

Or, I could have a Mustang- specific instructor drive my car and report. But I get too nauseous within 3 laps.

Yes, I've done a ton of track laps with no traffic before and after bar changes.

Balance is not as unknowable or mysterious as you might think if you have the seat time.

 

[NightmareMoon]

The Steeda competition bar is soft, for use with stiff springs, I have soft springs. I don’t see how moving to a softer bar will move me toward my goal of less body roll. Less rear bar also increases understeer, again opposite of my ultimate goal of maintaining current PP2 stiffness ratio, front to rear.
I think the standard Steeda bars, Steeda part #’s 555-1015 and 1016 will accomplish my goals.

Most of the aftermarket rear bars are too stiff.

That steed comp bar ... my calculations say it could be a better match than the normal steeda bar to keep your current front/rear ratio when paired with a BMR bar on medium. With a Steeda front bar you've listed it might be too soft.

 

[NightmareMoon]

Also FWIW spring rates (acting independently)dont change the balance as much as you might expect because in our situation here where the ride height is preserved for spring changes. With a given ride height the steady state weight on the front and rear tires is unchanged even though you may make a massive spring rate shift. Theres a lot of geometry to consider in a corner, so its not as simple as you’d think. I’ve observed this experimentally when nearly doubling my front spring rate. By an oversimplified analysis that should have cause massive bias shift to oversteer.

swaybars work very differently, because the bars do bet more involved in shifting balance when the vehicle rolls, because they increase rates as wheels on one side go up and the other side goes down. Its not at all the same as spring rates.

 

[S550HPP]

My Eibach front on full soft has been perfect plus I like that it's has zero welds and is heat treated so I expect consistency for years.

 

[GTP]

Yes, I've done a ton of track laps with no traffic before and after bar changes.

Balance is not as unknowable or mysterious as you might think if you have the seat time.

Say I have a rear bar with extra holes and I move the attachment to other holes. Will I easily notice a difference by the seat of my pants?

 

[Mikepol2]

In summary, I stiffened front springs while stiffening both bars, more so the rear bar. (I still don't understand why people recommend a real stiff front bar when our cars understeer as stock.)

Most of the aftermarket rear bars are too stiff.

That steed comp bar ... my calculations say it could be a better match than the normal steeda bar to keep your current front/rear ratio when paired with a BMR bar on medium. With a Steeda front bar you've listed it might be too soft.

My car did not understeer stock, and it feels like it is primarily due to the 305 fronts. The Steeda adjustable bars are definitely more suitable to PP1/non-HP Mach 1 tire setups. The Steeda front has 4 holes and the rear has three holes. I had it set to second stiffest front and softest rear and gassed it turning right at a red light and was almost backwards in the blink of an eye. It almost feels like for PP2/HP Mach tire set ups, keeping the stock rear bar would be a better match with second stiffest front on the Steeda bar. Will definitely be going to 325 rears when it’s time to replace the tires, I am trying to run them a little under pressured in the rear and a little over pressured front to compensate for the oversteer.

 

[NightmareMoon]

Say I have a rear bar with extra holes and I move the attachment to other holes. Will I easily notice a difference by the seat of my pants?

yeah you should, but you will need to get close enough to the limit to feel it.

Its all relative but of the car is close to balanced, a single hole change on either front or rear bar is significant.

 

[NightmareMoon]

My car did not understeer stock, and it feels like it is primarily due to the 305 fronts. The Steeda adjustable bars are definitely more suitable to PP1/non-HP Mach 1 tire setups. The Steeda front has 4 holes and the rear has three holes. I had it set to second stiffest front and softest rear and gassed it turning right at a red light and was almost backwards in the blink of an eye. It almost feels like for PP2/HP Mach tire set ups, keeping the stock rear bar would be a better match with second stiffest front on the Steeda bar. Will definitely be going to 325 rears when it’s time to replace the tires, I am trying to run them a little under pressured in the rear and a little over pressured front to compensate for the oversteer.

gassing it turning at a red light isnt normal oversteer, its throttle oversteer.

GASSING it from a stop in the lowest gear is going to spin ya in almost every rwd cars, even low power NA/NB miatas.

Its a rwd car, you’re going to be able to spin any car setup to understeer in that situation pretty easily. On track a balanced car will respond to small changes on throttle mid corner by pushing out (understeer) if you add a bit more than maintenance throttle or by tucking in (slight oversteer) if you lift. If you add more than mild power, or if uou forget to unwind the steering while adding gas, then that understeer will progress to oversteer which will stop if you gently back off. A great exit from a corner may flirt with this line between natural understeer from reasonable throttle and the rear kicking out from getting a bit aggressive.

An understeering car wont turn well in a maintenance throttle mid corner, and adding a little gas it will understeer worse, adding more gas it might go neutral but it will resist rotating enough to hit the ideal slip angles and then finally it will over rotate. An oversteering car will tuck nicely mid corner but may be very sensitive to lifting at all, and on corner exit it may go quickly to oversteer with moderate throttle requiring fast steering corrections in all sorts of directions to keep the nose ahead of the tail. Most people arent comfortable with that, and you wont be able to put as much power down, but it should be nice and quick on corner entry and able to point and dive down to the apex.

a neutral car and definitely one tuned with shock settings can be fast on corner entry and mid corner and also stable fast on corner exit. I’m experimenting with a different rear differential to get some understeer and throttle tolerance back on corner exit, allowing more of an oversteer bias for early phases of the corner. The big wing helps add stability (aka understeer) in faster corners too.

Stay safe out there

 

[Bossdog]

My car did not understeer stock, and it feels like it is primarily due to the 305 fronts. The Steeda adjustable bars are definitely more suitable to PP1/non-HP Mach 1 tire setups. The Steeda front has 4 holes and the rear has three holes. I had it set to second stiffest front and softest rear and gassed it turning right at a red light and was almost backwards in the blink of an eye. It . . .

In addition to 305’s in the front, your PP2 doesn’t under steer because Ford increased the rear PP2 bar by 67% over the PP1 bar ( and the front bar by only 12%)

here is a good tutorial on managing under steer and over steer

http://speed.academy/how-to-fix-understeer-or-oversteer-suspension-handling-setup-tuning/

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