New Sway Bar Option and Sway Bar Summary
09-08-2017, 08:07 AM
#76
So after having some fun on track over Saturday and Sunday, here are my findings:
Setup 1A (66.7% calculated FRC): Slight understeer, front tires heat more than the rears leading to more understeer once the tires have gone over their optimum temps. The rear was well planted exiting corners under full throttle. The car would push slightly to start with and then more noticeably as the tires overheated.
Setup 1B (61.7% calculated FRC): Neutral to very slight oversteer. Rears heat up slightly quicker than fronts. Once the tires had gone over their optimum temps the rears would drift a few % more than the fronts exiting a corner full throttle in 3rd gear.
Based on some rough tire temp measurements (used a probe in the garage after a session) I settled on hot pressures of around 32psi rear, 36.5psi front. Rear camber seemed about right. Front could have used a little more camber, but is already maxed out (hence the higher pressures to try and equalize tire temps). This is with a 14inch ride height. 17/255/40 Direzza Z2 tires.
Conclusion: Setup 1A felt 75% away from perfect, while 1B felt 25% away in the opposite direction. I need to try a stock miata (softer) rear bar, or more front camber/lower ride height). I'd really like to run with a softer front bar, and no rear but have not found a front bar with the appropriate stiffness.
Results may vary based on track, conditions, driver, and mental state. I'm also not really sure where I got the spring MR's from (Paimon?), nor how accurate they are, but it's all relative, so you can compare results to mine if you use the same ones.
Kudos to Shaikh at FCM for a really nice setup and being almost exactly spot on with his predictions.
Setup 1A (66.7% calculated FRC): Slight understeer, front tires heat more than the rears leading to more understeer once the tires have gone over their optimum temps. The rear was well planted exiting corners under full throttle. The car would push slightly to start with and then more noticeably as the tires overheated.
Setup 1B (61.7% calculated FRC): Neutral to very slight oversteer. Rears heat up slightly quicker than fronts. Once the tires had gone over their optimum temps the rears would drift a few % more than the fronts exiting a corner full throttle in 3rd gear.
Based on some rough tire temp measurements (used a probe in the garage after a session) I settled on hot pressures of around 32psi rear, 36.5psi front. Rear camber seemed about right. Front could have used a little more camber, but is already maxed out (hence the higher pressures to try and equalize tire temps). This is with a 14inch ride height. 17/255/40 Direzza Z2 tires.
Conclusion: Setup 1A felt 75% away from perfect, while 1B felt 25% away in the opposite direction. I need to try a stock miata (softer) rear bar, or more front camber/lower ride height). I'd really like to run with a softer front bar, and no rear but have not found a front bar with the appropriate stiffness.
Results may vary based on track, conditions, driver, and mental state. I'm also not really sure where I got the spring MR's from (Paimon?), nor how accurate they are, but it's all relative, so you can compare results to mine if you use the same ones.
Kudos to Shaikh at FCM for a really nice setup and being almost exactly spot on with his predictions.
My set up uses stock sway bars and I am running front 504 (9) and rear 336 (6) spring rates.
The front roll couple (FRC) is 62.3% and I consider this to be almost perfect. I need to run just a hair less damping in the rear then the front is dial it in where I like it. you can run the damping even clicks front and rear and the car is basically neutral.
I concur with your FRC numbers.
are you thinking about a strut bar? The sway bar goes under the car. If you have to ask, you don't need an upgraded one.
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RotaryMachineRx (10-13-2017)
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