Need help eliminating understeer
Need help eliminating understeer
Im having issues with excessive understeer on my evo 8. My suspension set up is:
AMR Race Coilovers -2f camber and -1.5 rear camber
Tanabe Front Sway Bar
Hotchkis Rear Sway Bar (on middle setting-27%)
Quaife LSD Differential w/ Shep Transfercase
Would changing the rear sway bar to the stiffest setting help? Also, what other mods would be good to get in order to get the best performance? Appreciate the help.
AMR Race Coilovers -2f camber and -1.5 rear camber
Tanabe Front Sway Bar
Hotchkis Rear Sway Bar (on middle setting-27%)
Quaife LSD Differential w/ Shep Transfercase
Would changing the rear sway bar to the stiffest setting help? Also, what other mods would be good to get in order to get the best performance? Appreciate the help.
I have the same goal for 2014, on my list to do is the Whiteline Roll Center Kit, Steering Precision, and Bump Steer Kit. That and an ACD reflash, I hear nothing but good things about the ACD reflash. The roll center kit will help lots depending on the height and everything you're set at.
car has not been corner balanced, i thought that is mainly if you are tracking it a lot. ive looked into the whiteline kit but was not sure at what level of modification it is recommended. i have the height set at 25" all around from the ground to center of the fender.
I am heavily considering the "Track" reflash from ACD-Tuning. http://www.acd-tuning.com/evo-7-9.html. It looks to be a fairly cheap yet very effective handling mod.
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IMO... camber up front isn't sufficient, and on a dedicated autoX/track car I do not run as much rear camber as you are running...
What tires are you on? and what are your spring rates? Thanks.
What tires are you on? and what are your spring rates? Thanks.
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Joined: Jul 2003
Posts: 638
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Two good threads below .... yes they are pretty old ....
https://www.evolutionm.net/forums/ev...ndersteer.html
https://www.evolutionm.net/forums/ev...-handling.html
https://www.evolutionm.net/forums/ev...ndersteer.html
https://www.evolutionm.net/forums/ev...-handling.html
Im having issues with excessive understeer on my evo 8. My suspension set up is:
AMR Race Coilovers -2f camber and -1.5 rear camber
Tanabe Front Sway Bar
Hotchkis Rear Sway Bar (on middle setting-27%)
Quaife LSD Differential w/ Shep Transfercase
Would changing the rear sway bar to the stiffest setting help? Also, what other mods would be good to get in order to get the best performance? Appreciate the help.
AMR Race Coilovers -2f camber and -1.5 rear camber
Tanabe Front Sway Bar
Hotchkis Rear Sway Bar (on middle setting-27%)
Quaife LSD Differential w/ Shep Transfercase
Would changing the rear sway bar to the stiffest setting help? Also, what other mods would be good to get in order to get the best performance? Appreciate the help.
I wouldn't tighten up the rear swaybar unless you have lots of FRONT spring/sway to keep the inside rear tire on the ground. With our improperly stacked USDM 1 way rear diff inefficient at putting down the power as it is, lifting the wheel mid air would only exacerbate the problem.
As mentioned above, what are your current spring rates?
A restacked (I'd recommend at least a Weir 12 plate, if not a TRE 1.5 way depending on your budget) rear diff would help tremendously on corner exits, while an ACD reflash will help greatly with turn in and mid corner.
As mentioned above, what are your current spring rates?
A restacked (I'd recommend at least a Weir 12 plate, if not a TRE 1.5 way depending on your budget) rear diff would help tremendously on corner exits, while an ACD reflash will help greatly with turn in and mid corner.
Two good threads below .... yes they are pretty old ....
https://www.evolutionm.net/forums/ev...ndersteer.html
https://www.evolutionm.net/forums/ev...-handling.html
https://www.evolutionm.net/forums/ev...ndersteer.html
https://www.evolutionm.net/forums/ev...-handling.html
The middle settling as stated is confusing, not -27%, but +27%as you can see here are the setting stiffness for each of the holes 3 Position Rear +10%, +27%, +47%, and you substancialy increase stiffness if you went to the third hole @ 47%. So yes to address your question that would make it stiffer but also may cause you to be tail happy--depending on your driving style and other component set up. If you research here you will also find most dont like the stiffest setting as it picks up the rear tire, But I drive mine on the street that way and have for yrs now without consequence--at speed it might be an issue. Again depends on the driver the set up and the speed. GL
I wouldn't tighten up the rear swaybar unless you have lots of FRONT spring/sway to keep the inside rear tire on the ground. With our improperly stacked USDM 1 way rear diff inefficient at putting down the power as it is, lifting the wheel mid air would only exacerbate the problem.
As mentioned above, what are your current spring rates?
A restacked (I'd recommend at least a Weir 12 plate, if not a TRE 1.5 way depending on your budget) rear diff would help tremendously on corner exits, while an ACD reflash will help greatly with turn in and mid corner.
As mentioned above, what are your current spring rates?
A restacked (I'd recommend at least a Weir 12 plate, if not a TRE 1.5 way depending on your budget) rear diff would help tremendously on corner exits, while an ACD reflash will help greatly with turn in and mid corner.
FWIW, I think that is way too much rear camber... I DD'd my car 365days a year for the first 3years I owned it... and never would I have had that much rear camber...
Also I wouldn't think a square setup on springs is the way to go, I won't get into a whole motion ratio conversation, but most good handling EVOs will have a higher spring rate in the rear..
Any reason you have yet to share your toe f/r as well?
Also I wouldn't think a square setup on springs is the way to go, I won't get into a whole motion ratio conversation, but most good handling EVOs will have a higher spring rate in the rear..
Any reason you have yet to share your toe f/r as well?
For a square setup (my personal favorite way to set up an evo), you do need more rear bar. With the bigger front bar you have, the Hotchkiss needs to be at full stiff. I would also look at getting the cusco swaybar bracket up front and running softer.
More rear bar for you will help increase rear transfer and reduce load on the front inside tire. Softening front bar will also reduce front weight transfer, both increasing front grip.
One thing to understand though, understeer is largely impossible to fully get rid of at steady state. My car has a very high limit but on hot tires, the front will still push at steady state. Transitions are completely diferent, but with SS you're stuck dealing with the 65% front weight.
More rear bar for you will help increase rear transfer and reduce load on the front inside tire. Softening front bar will also reduce front weight transfer, both increasing front grip.
One thing to understand though, understeer is largely impossible to fully get rid of at steady state. My car has a very high limit but on hot tires, the front will still push at steady state. Transitions are completely diferent, but with SS you're stuck dealing with the 65% front weight.
Stolen from *gasp* NASIOC:
TO REDUCE UNDERSTEER or INCREASE OVERSTEER:
Front tires:
- Increase tire pressure in 2.5psi increments
- Increase Section Width
- Lower the Aspect Ratio
- Reduce front tread depth
Rear Tires:
- Reduce tire pressure in 2.5psi increments
- Reduce section width
- Install higher aspect ratio tires
- Increase rear tread depth
Front Wheels:
- Install wider wheels
- Install lighter wheels
Rear Wheels:
- Install narrower wheels
- Install heavier wheels
Front Alignment settings:
- Dial in more negative camber
- Dial in More toe-out
- Dial in more positive caster
Rear Alignment settings:
- Dial in more positive camber
- Dial in more toe-out (Same as front)
Anti-Sway bars:
- Soften the Front
- Stiffen the Rear
Spring rates:
- Soften the Front
- Stiffen the Rear
Shock absorbers:
- Soften the Front
- Stiffen the Rear
Suspension Bushings:
- Soften the Front
- Stiffen the Rear
Brake Proportioning
- Reduce Front brake pressure
- Increase rear pressure
Weight Distribution
- Reduce front weight
- Increase rear weight
Aerodynamics:
- Increase Front Downforce
- Reduce rear downforce
---------------------------------------------------------------------------------
TO REDUCE OVERSTEER or INCREASE UNDERSTEER:
Front tires:
- Decrease tire pressure in 2.5psi increments
- Decrease Section Width
- Install higher Aspect Ratio tires
- Increase front tread depth
Rear Tires:
- Increase tire pressure in 2.5psi increments
- Increase section width
- Reduce aspect ratio
- Decrease rear tread depth
Front Wheels:
- Install narrower wheels
- Install heavier wheels
Rear Wheels:
- Install wider wheels
- Install lighter wheels
Front Alignment settings:
- Dial in less negative camber
- Dial in less toe-out (to toe-in if needed)
- Dial in less positive caster
Rear Alignment settings:
- Dial in less positive camber
- Dial in less toe-out (Same as front)
Anti-Sway bars:
- Stiffen the Front
- Soften the Rear
Spring rates:
- Stiffen the Front
- Soften the Rear
Shock absorbers:
- Stiffen the Front
- Soften the Rear
Suspension Bushings:
- Stiffen the Front
- Soften the Rear
Brake Proportioning
- Increase Front brake pressure
- Reduce rear brake pressure
Weight Distribution
- Increase front weight
- Decrease rear weight
Aerodynamics:
- Reduce Front Downforce
- Increase rear downforce
Front tires:
- Increase tire pressure in 2.5psi increments
- Increase Section Width
- Lower the Aspect Ratio
- Reduce front tread depth
Rear Tires:
- Reduce tire pressure in 2.5psi increments
- Reduce section width
- Install higher aspect ratio tires
- Increase rear tread depth
Front Wheels:
- Install wider wheels
- Install lighter wheels
Rear Wheels:
- Install narrower wheels
- Install heavier wheels
Front Alignment settings:
- Dial in more negative camber
- Dial in More toe-out
- Dial in more positive caster
Rear Alignment settings:
- Dial in more positive camber
- Dial in more toe-out (Same as front)
Anti-Sway bars:
- Soften the Front
- Stiffen the Rear
Spring rates:
- Soften the Front
- Stiffen the Rear
Shock absorbers:
- Soften the Front
- Stiffen the Rear
Suspension Bushings:
- Soften the Front
- Stiffen the Rear
Brake Proportioning
- Reduce Front brake pressure
- Increase rear pressure
Weight Distribution
- Reduce front weight
- Increase rear weight
Aerodynamics:
- Increase Front Downforce
- Reduce rear downforce
---------------------------------------------------------------------------------
TO REDUCE OVERSTEER or INCREASE UNDERSTEER:
Front tires:
- Decrease tire pressure in 2.5psi increments
- Decrease Section Width
- Install higher Aspect Ratio tires
- Increase front tread depth
Rear Tires:
- Increase tire pressure in 2.5psi increments
- Increase section width
- Reduce aspect ratio
- Decrease rear tread depth
Front Wheels:
- Install narrower wheels
- Install heavier wheels
Rear Wheels:
- Install wider wheels
- Install lighter wheels
Front Alignment settings:
- Dial in less negative camber
- Dial in less toe-out (to toe-in if needed)
- Dial in less positive caster
Rear Alignment settings:
- Dial in less positive camber
- Dial in less toe-out (Same as front)
Anti-Sway bars:
- Stiffen the Front
- Soften the Rear
Spring rates:
- Stiffen the Front
- Soften the Rear
Shock absorbers:
- Stiffen the Front
- Soften the Rear
Suspension Bushings:
- Stiffen the Front
- Soften the Rear
Brake Proportioning
- Increase Front brake pressure
- Reduce rear brake pressure
Weight Distribution
- Increase front weight
- Decrease rear weight
Aerodynamics:
- Reduce Front Downforce
- Increase rear downforce