RE Notes 12/30/2015

12/30/ 2015

Working on my car, I came to the conclusion that I may not be the only one trying new things to correct old car handling problems.   So below are some ideas on how to correct some of the problems we may have.  This is a collection of things I have learned or found on the internet, and some are ideas that come up in conversations during an autocross event.  Depending on the  class of your car you may or may not be able to make some of these changes.  But I tried to cover as much as I could, it’s not all but a good list to start with!

Understeer: Push, plowing, front tires slide out first.  How to correct:

Tires:

  • Raise front tire pressure •Lower rear tire pressure •Install shorter front tires •Install taller rear tires  •Install wider front tires  •Install narrower rear tires •Use softer front compound  •Use harder rear compound

Chassis:

  • Soften front shocks •Soften front springs •Soften front sway bar •Stiffen rear shocks  •Stiffen rear springs  • Stiffen rear sway bar  •Lower front end  •Raise rear end  •Widen front track  •More front toe out  •Reduce rear toe in  •Slightly increase front negative camber  •Increase positive caster   •May need more front  suspension travel   •Remove weight from front of vehicle  •Add weight to rear of vehicle  •Increase front wing downforce  •Too much front brake bias  •Drive a different line

Vehicle slides (both ends),  does not corner to full potential.  How to correct:

  • Raise front and rear tire pressures slightly •Suspension may be too soft •Shocks may be too soft  •Roll center may be too high  •Lower vehicle •Tires may be too hard  •Widen track front & rear track

Oversteer: 
Loose, rear tires slide out first.  I like my car a little loose.  How to correct:

Tires:

  • Lower front tire pressure •Raise rear tire pressure •Install taller front tires •Install shorter rear tires •Install narrower front tires •Install wider rear tires  •Use harder front compound •Use softer rear compound

Chassis:   

  • Stiffen front shocks •Soften rear shocks •Stiffen front sway bar •Soften rear sway bar  •Stiffen front springs  •Soften rear springs  •Raise front end   •Lower rear end  •More front toe-in  •Increase rear toe-in  •Reduce front negative camber  •Reduce positive caster •May need more rear suspension travel  •If possible add weight to front of vehicle  •Remove weight from rear of vehicle  •Too much rear brake bias •Increase rear wing downforce  •You may be going in too deep into turns •You may be getting on the throttle to early exiting turns

I would like to note that when I try to correct the handling of the car, I always try to correct and work on the end that has the problem.  Like, if the car has an understeer,  front tires are losing their grip, I try to make corrections the front of the car first, hopefully increasing that grip level. Normal I always try things from easy to hard, like drive a different line and raise front tire pressure.  Changing my brake bias has made the biggest improvement so far!   Most of you know your car pretty well and just may know where to make corrections next.  If not try some of the things I have listed.

 

Stanley