Eibach sways w/ Bilstein B8, -3.9 camber, -1.25" ride height

[ZDan]

Originally Posted by SCFD

I'm not completely sure but see if you can dig up some information on the Tanabe 22 mm hollow front sway bar. I suspect it might be close to what you're looking for.

Thanks, but I went with Eibach, a never-used set for reasonable $$$ found me Looking forward to Palmer, must exact revenge on evil Miata...

[M0nk3y]

Originally Posted by strat61caster

Sounds not that different from an SSC setup, I know they were having issues with rear swaybar binding and terrible angle with the ~1" lowering and stock endlinks on the Eibach rear bar, full stiff was the only setting a lot of people could make work but other factors might have been at play for taht, this year they are allowing aftermarket/adjustable links to help the problem. I'd budget for adjustable endlinks front and rear.

@M0nk3y any reason you didn't split the holes? stiff on one side, soft on the other?

Edit; big list of swaybar options, if you've got the cash to burn monkey is right, Karcepts has the biggest adjustment range that starts where you're interested in, looks like most are either less then twice as stiff or more, Karcepts page also has good reference for stiffness values when comparing since one companies 100% is the same as another companies 200%.

https://www.ft86club.com/forums/showthread.php?t=49659

http://www.karcepts.com/shop/product.php?id_product=136

I was full soft on the 22mm, full stiff on the 20mm. No way to split holes

[ZDan]

Originally Posted by M0nk3y

I was full soft on the 22mm, full stiff on the 20mm. No way to split holes

Splitting holes is generally going to be a bad idea, see previous posts...

What you desire (presumably):
Finer control of how the outside front loads up vs. outside rear during cornering to provide finer control of handling balance

What splitting holes will do:
Induce asymmetric loading/unloading of outside front vs. outside rear in left-handers vs. right-handers (defeating your original purpose of having finer control of this). While you will have "adjusted" the *average* roll stiffness at that end of the car by the desired finer increment, you also create a situation where the outside front is effectively stiffer for turns in one direction than the opposite outside front is for turns in the other direction. On *average*, you've achieved what you want. But it's going to give you a bigger difference in the desired direction for turns in the one direction, and a smaller difference or even a difference in the undesired direction for turns in the opposite direction.

In addition, you create imbalanced L/R loading at both the front and rear under braking and acceleration, even in a straight line. Straight-line braking will now additionally load up one of the fronts more than the other, and further unload the same-side rear by the same amount.


If you *specifically* want to change under/oversteer behavior differently for left- vs. right-handers, and have no other mechanism to do this, *maybe*? But that would be better addressed by weight-jacking via individual ride height adjustments to get imbalanced corner weights.

[M0nk3y]

Originally Posted by ZDan

Splitting holes is generally going to be a bad idea, see previous posts...

What you desire (presumably):
Finer control of how the outside front loads up vs. outside rear during cornering to provide finer control of handling balance

What splitting holes will do:
Induce asymmetric loading/unloading of outside front vs. outside rear in left-handers vs. right-handers (defeating your original purpose of having finer control of this). While you will have "adjusted" the *average* roll stiffness at that end of the car by the desired finer increment, you also create a situation where the outside front is effectively stiffer for turns in one direction than the opposite outside front is for turns in the other direction. On *average*, you've achieved what you want. But it's going to give you a bigger difference in the desired direction for turns in the one direction, and a smaller difference or even a difference in the undesired direction for turns in the opposite direction.

In addition, you create imbalanced L/R loading at both the front and rear under braking and acceleration, even in a straight line. Straight-line braking will now additionally load up one of the fronts more than the other, and further unload the same-side rear by the same amount.


If you *specifically* want to change under/oversteer behavior differently for left- vs. right-handers, and have no other mechanism to do this, *maybe*? But that would be better addressed by weight-jacking via individual ride height adjustments to get imbalanced corner weights.

With a Karcepts bar changes within lever arm lengths remain constant. Any other bar I'd agree

[ZDan]

Originally Posted by M0nk3y

With a Karcepts bar changes within lever arm lengths remain constant. Any other bar I'd agree

It looks to me like Karcepts, as with most other adjustable sway bars, gives different sway bar stiffness options by having different endlink attachment locations. Position the end links closer to the pivot bushings and you have a stiffer sway bar. Attach the L/R end links at different positions and you're giving one end greater mechanical advantage, you will effectively be stiffening one end more than the other as described in previous posts. It's a bad idea and Karcepts shouldn't be touting this as a way to have 7 stiffness settings vs. 4.

[M0nk3y]

Originally Posted by ZDan

It looks to me like Karcepts, as with most other adjustable sway bars, gives different sway bar stiffness options by having different endlink attachment locations. Position the end links closer to the pivot bushings and you have a stiffer sway bar. Attach the L/R end links at different positions and you're giving one end greater mechanical advantage, you will effectively be stiffening one end more than the other as described in previous posts. It's a bad idea and Karcepts shouldn't be touting this as a way to have 7 stiffness settings vs. 4.

LOL.

got it. i'll make sure he's aware of it.....

[ZDan]

OK, because these things stick with me until resolved, my further thoughts follow
TL/DR: splitting swaybar stiffness setting left/right *is not as bad as I had thought*, and shouldn't muck with corner weights much if at all, but still does induce asymmetric responses in the suspension/chassis and still kinda gross IMO...

With asymmetric swaybar setting, you do get different force reactions at the endlinks, and you do get torsion in the bar under straightline braking (or acceleration). However these asymmetric forces are reacted into the chassis at the pivot mounts to the chassis. So you're not (I don't think) weight-jacking *on net* (I don't think...). However, you *are* putting some twist in the bar under pure straight-line braking, and different forces are being reacted through the springs vs. sway bar left vs. right side.

Example:
Say you have 1000 lb. vertical force at each front tire under straight-line braking, 2" suspension compression. With a split setup, arm lengths differing by 10%, you're enforcing a ~0.2" different displacement at the endlinks. Say it's a 500 lb/in bar on the stiff side, 450 lb/in on soft side, that's 100 lb. acting UP on one end of the bar and 90 lb. acting *down* on the other. The 100 lb. upload on the swaybar at the one end is reacted with a 100 lb. download at the bushing/pivot on that side. 90 lb. download at other end reacted with 90 lb. upload at bushing/pivot on that side. So on one side the spring is seeing ~1100 lb. compression, vs. other side at ~910 lb. Kinda goof-ass if you ask me... But probably not the end of the world either. Still think there will be some residual difference in handling through left-handers vs. right-handers due to different stiffnesses/compliances through the different paths (spring path vs. swaybar path), but whatevs...

Whew...

For me, not worth it to induce asymmetric L/R behavior in the suspension to gain fine-tuning of dubious benefit on a softly-sprung, no-downforce, lightly-modded production car...

Optimal setup should be relatively insensitive to small changes anyway. Any time I've been in a position where I've *needed* to change F/R balance with sways, a BIG change has been required, much bigger than increments in an adjustable bar. More like removing one bar entirely or replacing a stiff aftermarket bar with much softer factory bar at one end.

Anyway, carry on as thou desireth!

[Calum]

Originally Posted by ZDan

OK, because these things stick with me until resolved, my further thoughts follow
TL/DR: splitting swaybar stiffness setting left/right *is not as bad as I had thought*, and shouldn't muck with corner weights much if at all, but still does induce asymmetric responses in the suspension/chassis and still kinda gross IMO...

With asymmetric swaybar setting, you do get different force reactions at the endlinks, and you do get torsion in the bar under straightline braking (or acceleration). However these asymmetric forces are reacted into the chassis at the pivot mounts to the chassis. So you're not (I don't think) weight-jacking *on net* (I don't think...). However, you *are* putting some twist in the bar under pure straight-line braking, and different forces are being reacted through the springs vs. sway bar left vs. right side.

Example:
Say you have 1000 lb. vertical force at each front tire under straight-line braking, 2" suspension compression. With a split setup, arm lengths differing by 10%, you're enforcing a ~0.2" different displacement at the endlinks. Say it's a 500 lb/in bar on the stiff side, 450 lb/in on soft side, that's 100 lb. acting UP on one end of the bar and 90 lb. acting *down* on the other. The 100 lb. upload on the swaybar at the one end is reacted with a 100 lb. download at the bushing/pivot on that side. 90 lb. download at other end reacted with 90 lb. upload at bushing/pivot on that side. So on one side the spring is seeing ~1100 lb. compression, vs. other side at ~910 lb. Kinda goof-ass if you ask me... But probably not the end of the world either. Still think there will be some residual difference in handling through left-handers vs. right-handers due to different stiffnesses/compliances through the different paths (spring path vs. swaybar path), but whatevs...

Whew...

For me, not worth it to induce asymmetric L/R behavior in the suspension to gain fine-tuning of dubious benefit on a softly-sprung, no-downforce, lightly-modded production car...

Optimal setup should be relatively insensitive to small changes anyway. Any time I've been in a position where I've *needed* to change F/R balance with sways, a BIG change has been required, much bigger than increments in an adjustable bar. More like removing one bar entirely or replacing a stiff aftermarket bar with much softer factory bar at one end.

Anyway, carry on as thou desireth!

The bar isn't exerting a force on the chassis. Under straight line braking the bar does nothing buy swivel slightly in the mount bushings. It only transfers any force when the displacemt side to side is different. .

[ZDan]

Originally Posted by Calum

The bar isn't exerting a force on the chassis. Under straight line braking the bar does nothing buy swivel slightly in the mount bushings. It only transfers any force when the displacemt side to side is different. .

Normally, with the end links in the same adjustment holes on both sides, yes. But in the case of split stiffness settings, forces are induced in the bar and reacted at the pivot bushings. Because as the chassis dives , if you have one end of the sway bar with a 9" lever arm and 10" lever arm on the other side, loads will be induced in the swaybar and endlinks.

[Calum]

I see it now, thanks.

[ZDan]

Hmm, it now occurs to me that *if* the car is to remain left/right even under straight-line braking, then the left/right front spring forces *must* be equal. But with asymmetric swaybar stiffness settings, there *will* be asymmetric loading in the sway bar (short lever end sees compression in end-link, long-lever end sees tension) with equal L/R suspension compression. The only conclusion is that asymmetric swaybar settings must lead to non-uniform front suspension loading under straight-line braking, i.e. dynamic weight-jacking. I think I'll have to build a 3D sim to quantify it though...

[TunaNoCrust]

Originally Posted by ZDan

must exact revenge on evil Miata...

All BRZ/86 podium!

[ZDan]

Originally Posted by TunaNoCrust

All BRZ/86 podium!

Hellzyeh! Gonna be a tall order vs. Miatae on Hoosiers tho, Paul G just got a set of R7s and David W is on them as well...

50/50 Miatas with double-wishbone suspension have 2.5/5.0/7.5 "performance adjustment points" for NA-NB/NC/ND.
But nose-heavy 55/45 FT86s with strut front suspension get 7.5 non-Brembo, and 9.0 with Brembos! Thass some b.s. right there, shenanigans!

[TunaNoCrust]

Originally Posted by ZDan

Hellzyeh! Gonna be a tall order vs. Miatae on Hoosiers tho, Paul G just got a set of R7s and David W is on them as well...

50/50 Miatas with double-wishbone suspension have 2.5/5.0/7.5 "performance adjustment points" for NA-NB/NC/ND.
But nose-heavy 55/45 FT86s with strut front suspension get 7.5 non-Brembo, and 9.0 with Brembos! Thass some b.s. right there, shenanigans!

Yeah you aren't kidding! And I think Troy V upgraded his coilovers. Lots of talented drivers in T50 and most of them did a lot of modifications this year and I am over here with my only modification being new tires