Need sway bar expert

[paulydee]

I need someone to explain to me why removing the rear swaybar on a ITS second gen helps reduce understeer. Every convention say that a thicker rear sway bar would reduce under steer. Incidentally I did remove my rear to help eliminate understeer. I know it works I just need to know why?

Paul D'Angelo
www.iridiumracing.com

 

[Karl Bocchieri]

Paul,
I suggest you read Caroll Smith's Tune to Win. There is alot about suspension set up and tuning that can't be covered in an E-mail.
Simple to remember, stiffen an end of the car (with springs,shocks or sway bar) and you increase understeer in front or make the car loose in the rear. RX-7's are almost always loose in the rear, so you want to increase the grip at the rear which can be done by using softer springs and no rear sway bar. Small changes can be done with shock adjustment.
The rear sway bar causes oversteer on an RX-7 which does not eliminate understeer but just masks it, and it's not the fast way to do it.

 

[Quickshoe]

Paulydee,

Not sure why it worked for you (placebo?). You're right it shouldn't.

Maybe there is something unique to the 2nd gen? Does the suspension design(geometry) lead to something unconventional during moments of roll, bump, droop?

I have a friend with lots of racing experience. He is the only one in our circle of racing friends who does things backwards (i.e. removing a rear bar to decrease a push). He seems to think that it works that way. Maybe subconciously he alters his driving style to obtain the expected result? Who knows? When he's beating me on the track I'll revisit his tuning secrets.

FWIW, when tuning to find a balance I always try to fix the end that doesn't work, as opposed to making the working end worse. Either way will find a balance, but have you lost anything, overall? I'll only try to make the "good" end worse when I am out of adjustment options at the "bad" end. Or the adjustment required is so minimal that I need to use the rear for tuning. Often times the front end can be used for large changes and the rear is used to fine tune.