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Looking for the proper setting for the anti-roll bars

41
19
Exp. Type
HPDE
Exp. Level
Under 3 Years
Greenbrier, TN
I have been running my Eibach bars in the center hole and I’m not sure if that’s where I need to be? Here is the set up. I’ve been reading up but I’m getting some conflicting posts about sof/rear on the s550. This is not a daily driver Just an HPDE car so I’m thinking of the best track day setting.
I’m still on the Ford PP staggered wheels and Pilot 4S until I get the $$ for 18x11’s and better tires.
but here is the set up so far.
Eibach 35145.310 red 3 hole adjustable front bar
Eibach 35145.312 red 3 way adjustable rear bar
Eibach 4.14535 sport line lowering spring kit. 1.5” front 1.3” rear
Koni yellow shocks/struts
Do I stiffen the rear? Soften the front. Or will that cause more understeer?
Thanks guys.
 
111
93
Exp. Type
HPDE
Exp. Level
20+ Years
NC
I have been running my Eibach bars in the center hole and I’m not sure if that’s where I need to be? Here is the set up. I’ve been reading up but I’m getting some conflicting posts about sof/rear on the s550. This is not a daily driver Just an HPDE car so I’m thinking of the best track day setting.
I’m still on the Ford PP staggered wheels and Pilot 4S until I get the $$ for 18x11’s and better tires.
but here is the set up so far.
Eibach 35145.310 red 3 hole adjustable front bar
Eibach 35145.312 red 3 way adjustable rear bar
Eibach 4.14535 sport line lowering spring kit. 1.5” front 1.3” rear
Koni yellow shocks/struts
Do I stiffen the rear? Soften the front. Or will that cause more understeer?
Thanks guys.
Ok, time to answer your own question. How do you feel the car handles? Does it understeer on corner entry, neutral, or a little tail happy? same questions at apex and at track out.
 
41
19
Exp. Type
HPDE
Exp. Level
Under 3 Years
Greenbrier, TN
The car feels good in the Esses. Where I have the most trouble are corners like 6 at AMP Atlanta and at Barber turns 5&6. If you are familiar with them.
If I don’t scrub enough speed before the turn, It understeers, it pushes. If I get back on the gas too early at apex the rear gets a little loose. It comes right back in if I back off the throttle. track out is great. you get on the gas and it goes right where you want it to. (track out is where I feel most confident with the car).
 
48
33
Exp. Type
HPDE
Exp. Level
Under 3 Years
TX
Sway bars like springs respond to displacement. Springs contribute more to roll stiffness than do ARB's. You want to use ARB's to fine tune steady state cornering and how fast you want the car to transition left- to- right. You will more than likely want to soften the rear ARB relative to the front.

In general;
-Stiffer front will cause understeer
-Stiffer rear will cause oversteer

-Too much ARB stiffness and you will pick up the inside tire on hard cornering. This is bad as it reduces your contact with the road, 3 wheels on the ground will corner slower than 4 wheels.

*You may want to tune your turn in by adding camber or taking some toe out of the front

It's hard to know what you 'should' be doing since your car setup is unique to you as is your driving.
 
41
19
Exp. Type
HPDE
Exp. Level
Under 3 Years
Greenbrier, TN
Thanks Shatterpoints. If I understand what you are saying, the idea is to loose the body roll (via spring rate) and use ARB stiffness to help plant the wheels. But not so stiff that it picks the inside wheel up? Then the camber to help keep more tread surface on the pavement at the extreme angles of those sharp turns? How does the toe in/out work into the equation?
 
3,446
3,198
-Too much ARB stiffness and you will pick up the inside tire on hard cornering. This is bad as it reduces your contact with the road, 3 wheels on the ground will corner slower than 4 wheels.
It's hard to know what you 'should' be doing since your car setup is unique to you as is your driving.
well... not always, the S197 was notorious for lifting the inside tire under hard cornering
qGKqzwcl.jpg

If I don’t scrub enough speed before the turn, It understeers, it pushes
Softer front bar, softer springs (I'm a fan of the softest springs available) also you may need to address the rate of shock compression, (try speeding it up first)
If I get back on the gas too early at apex the rear gets a little loose.
roll into the throttle, softer rear spring or shock settings. (see above pic)
It comes right back in if I back off the throttle. track out is great.
In real life, jumping out of the throttle will promote snap oversteer due to a rapid weight redistribution, in your case, you are simple spinning the tires, so when you back out, the car handles neutral
track out is great. you get on the gas and it goes right where you want it to.
because you are no longer spinning the rear tires

There's so much to this, last week we were at Lime Rock, the inside of the tire was worn (dragging camber down the straights) then the outside half was worn (in the corner) what was odd is that the inside half of the tire was not worn, except the edge where it was going down the straight. This would be an indication where the shock was either bad, or it compressed too fast, basically allowing the tire to transition from the inner edge to the outside half of the tire, without really using the inside half.
If you can imagine that spring rate is a gross adjustment, anti roll bars are a finer adjustment, then shocks are an even finer adjustment, sort of defining where the spring and roll bar are applied, and finally, view the tire as part of the suspension as well because PSI is spring rate.
Also don't go into the rabbit hole of death, if the front doesn't stick, instead of doing all sorts of crazy adjustments to the front (or rear if it's loose) you may want to make the rear of the car stiffer so it rotates, instead of over sticking the front, making the car "too tight" to drive. At some point, in any given corner, you may experience both characteristics, there's no written in stone, fix for it. I know this muddies the water considerably, but try to break the corner into 3 spots, entry, center and exit, the old S197 wasn't so great in the center, but it sure got in and out really, really good, and more than made up for it.
 
48
33
Exp. Type
HPDE
Exp. Level
Under 3 Years
TX
Thanks Shatterpoints. If I understand what you are saying, the idea is to loose the body roll (via spring rate) and use ARB stiffness to help plant the wheels. But not so stiff that it picks the inside wheel up? Then the camber to help keep more tread surface on the pavement at the extreme angles of those sharp turns? How does the toe in/out work into the equation?
As a general rule of thumb yes.
well... not always, the S197 was notorious for lifting the inside tire under hard cornering
View attachment 66838
Looks like daylight under the inside rear too! I totally get it's a compromise amongst many things. A lot of the time it is due to limitations given by the league // series that you're running in. In a perfect world 4 tires // more contact patch = more grip = faster times. While not wrong is not always attainable.
 
41
19
Exp. Type
HPDE
Exp. Level
Under 3 Years
Greenbrier, TN
well... not always, the S197 was notorious for lifting the inside tire under hard cornering
View attachment 66838

If I don’t scrub enough speed before the turn, It understeers, it pushes
Softer front bar, softer springs (I'm a fan of the softest springs available) also you may need to address the rate of shock compression, (try speeding it up first)
If I get back on the gas too early at apex the rear gets a little loose.
roll into the throttle, softer rear spring or shock settings. (see above pic)
It comes right back in if I back off the throttle. track out is great.
In real life, jumping out of the throttle will promote snap oversteer due to a rapid weight redistribution, in your case, you are simple spinning the tires, so when you back out, the car handles neutral
track out is great. you get on the gas and it goes right where you want it to.
because you are no longer spinning the rear tires

There's so much to this, last week we were at Lime Rock, the inside of the tire was worn (dragging camber down the straights) then the outside half was worn (in the corner) what was odd is that the inside half of the tire was not worn, except the edge where it was going down the straight. This would be an indication where the shock was either bad, or it compressed too fast, basically allowing the tire to transition from the inner edge to the outside half of the tire, without really using the inside half.
If you can imagine that spring rate is a gross adjustment, anti roll bars are a finer adjustment, then shocks are an even finer adjustment, sort of defining where the spring and roll bar are applied, and finally, view the tire as part of the suspension as well because PSI is spring rate.
Also don't go into the rabbit hole of death, if the front doesn't stick, instead of doing all sorts of crazy adjustments to the front (or rear if it's loose) you may want to make the rear of the car stiffer so it rotates, instead of over sticking the front, making the car "too tight" to drive. At some point, in any given corner, you may experience both characteristics, there's no written in stone, fix for it. I know this muddies the water considerably, but try to break the corner into 3 spots, entry, center and exit, the old S197 wasn't so great in the center, but it sure got in and out really, really good, and more than made up for it.
Holy Cow! you can almost fit a helmet in the airspace under that tire! I understand exactly what you are saying about the spring rates. I'm going to start with some shock & tire pressure adjustments. (and work on my driving as well)
 

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