Added Cusco braces and now understeers....now what?
May 4, 2009, 05:28 AM
#1
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Added Cusco braces and now understeers....now what?
Add the Lower Arms Bar Version 1 and 2, and Front Center. Currently, I have Ohlins coilover - lower about 0.5" from stock height...so don't think that the geometry is off. I have stock front tower brace and DC Sport rear tower brace. This is an Evo 9 with setting Tarmac on road course. The tires are Continental SportContact 2.
Before adding the brace, it has a minor understeer. Now, the understeer is very noticeable...same shock/center diff setting.
I brake/double clutch downshift....turn the wheel....trailbrake into the corner...hit apex.....gently increase the gas. Standard procedure. The understeer exhibits heavily in the turn in.
Any idea?
Increase front sway bar size?
Add their complete brace kit?
Change the front tower bar?
Increase front Camber?
I would've expected increase rigidity in the front would help the front to get more grip, inducing oversteer....
Before adding the brace, it has a minor understeer. Now, the understeer is very noticeable...same shock/center diff setting.
I brake/double clutch downshift....turn the wheel....trailbrake into the corner...hit apex.....gently increase the gas. Standard procedure. The understeer exhibits heavily in the turn in.
Any idea?
Increase front sway bar size?
Add their complete brace kit?
Change the front tower bar?
Increase front Camber?
I would've expected increase rigidity in the front would help the front to get more grip, inducing oversteer....
May 4, 2009, 06:51 AM
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You may want to also ask this question in the "Evo Tires, Wheels, Brakes & Suspension" or "Motor Sports" section.
I didn't notice you saying anything about currently having upgraded front or rear sway bars or any other suspension mods. Have you considered replacing the rear trailing arm bushings and installing a rear bump-steer correction kit? I suppose that for the time being you could adjust your front rear camber settings (i.e., more front camber, less rear), or adjust your tire pressures.
l8r)
I didn't notice you saying anything about currently having upgraded front or rear sway bars or any other suspension mods. Have you considered replacing the rear trailing arm bushings and installing a rear bump-steer correction kit? I suppose that for the time being you could adjust your front rear camber settings (i.e., more front camber, less rear), or adjust your tire pressures.
l8r)
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May 17, 2009, 01:31 PM
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i have NOT seen much of an effect on under/over steer by installing rear heim joints for end links and whiteline bump steer.
check toe!!. re-check alignment for camber, you did not post what it is and it may have been affected by the mere process of installation.
also, i am not trying to be a dick, but you may be experiencing slower turn in more, as the car is now a bit more direct in the steering feel (since you made it more rigid).
check toe!!. re-check alignment for camber, you did not post what it is and it may have been affected by the mere process of installation.
also, i am not trying to be a dick, but you may be experiencing slower turn in more, as the car is now a bit more direct in the steering feel (since you made it more rigid).
Jun 2, 2009, 05:48 AM
#4
Before you do anything else you MUST have the car's alignment checked. The toughest thing to find is a good alignment shop with calibrated alignment eauipment, but it will make all the difference in the world.
Alignment WILL affect your car's handling.
Since you have lowered your car did you compensate for the lowered roll center with a Whiteline roll center kit? Lowering your front suspension will bring the roll center BELOW GROUND and even though you have a lower center of gravity it will understeer. The kit bring it back up above ground level.
What you want is about -2.00 degrees camber on the front with zero toe and -1.7 degrees camber on the back with 1/16 degree toe. Try that before you do anything with anti-roll bars.
The Whiteline rear bumpsteer kit is also a good idea.
Alignment WILL affect your car's handling.
Since you have lowered your car did you compensate for the lowered roll center with a Whiteline roll center kit? Lowering your front suspension will bring the roll center BELOW GROUND and even though you have a lower center of gravity it will understeer. The kit bring it back up above ground level.
What you want is about -2.00 degrees camber on the front with zero toe and -1.7 degrees camber on the back with 1/16 degree toe. Try that before you do anything with anti-roll bars.
The Whiteline rear bumpsteer kit is also a good idea.
Last edited by jplgsx; Jun 16, 2009 at 05:03 AM.
Jun 20, 2009, 10:38 AM
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Well, before the braces......the body flexes to compensate for the force that put on the outer wheels. Now, the body is stiff, therefore more force will transfer to the outer wheels..so it's easier to break loose. There are few options..... Get a bigger rear sway bar, change the camber settings, and coilover settings......
Jul 1, 2009, 03:40 PM
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Before you do anything else you MUST have the car's alignment checked. The toughest thing to find is a good alignment shop with calibrated alignment eauipment, but it will make all the difference in the world.
Alignment WILL affect your car's handling.
Since you have lowered your car did you compensate for the lowered roll center with a Whiteline roll center kit? Lowering your front suspension will bring the roll center BELOW GROUND and even though you have a lower center of gravity it will understeer. The kit bring it back up above ground level.
What you want is about -2.00 degrees camber on the front with zero toe and -1.7 degrees camber on the back with 1/16 degree toe. Try that before you do anything with anti-roll bars.
The Whiteline rear bumpsteer kit is also a good idea.
Alignment WILL affect your car's handling.
Since you have lowered your car did you compensate for the lowered roll center with a Whiteline roll center kit? Lowering your front suspension will bring the roll center BELOW GROUND and even though you have a lower center of gravity it will understeer. The kit bring it back up above ground level.
What you want is about -2.00 degrees camber on the front with zero toe and -1.7 degrees camber on the back with 1/16 degree toe. Try that before you do anything with anti-roll bars.
The Whiteline rear bumpsteer kit is also a good idea.
+1 for good alignment
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Jul 3, 2009, 10:32 PM
#8
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pushing means the rear end is getting better traction than the front
improve the front,
concur with need to align, factory settings may/will not apply
dropping 1/2" will change geometry and align
some of the strut braces are more for looks than anything, if it doesn't go straight across it's not doing much. The factory front works because it's straight from the towers to the firewall. The front ones that go from tower to tower with a kink in either end to clear the engine are most likely not doing much.
sway-bars are a last resort but sometimes necessary.
improve the front,
concur with need to align, factory settings may/will not apply
dropping 1/2" will change geometry and align
some of the strut braces are more for looks than anything, if it doesn't go straight across it's not doing much. The factory front works because it's straight from the towers to the firewall. The front ones that go from tower to tower with a kink in either end to clear the engine are most likely not doing much.
sway-bars are a last resort but sometimes necessary.
Jul 3, 2009, 10:53 PM
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What are your springs rates? To make car rotate better, you want to have the rear to have higher spring rate than front. 7k/8k, 8k/9k 9k/10k is a safe DD setup for Ohlins.
Obviously have the rsb setting, tire pressure to match and fine tune as well as dampening. +1 to alignment, makes a big difference. Camber: -2.5/-1.4 Toe 0/0 or 0 / -1/32 . Try that.
Obviously have the rsb setting, tire pressure to match and fine tune as well as dampening. +1 to alignment, makes a big difference. Camber: -2.5/-1.4 Toe 0/0 or 0 / -1/32 . Try that.
Last edited by Pure EvoIX; Jul 21, 2009 at 08:29 PM.
Jul 14, 2009, 02:31 PM
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I added 1mm to the rear sway bar size when i first started tracking my 8
that added just a little oversteer that i needed to learn the car...
since then I've removed it and love the stock handling
adding all of the stuff up front evidently gave it more 'push' as i would of expected
that added just a little oversteer that i needed to learn the car...
since then I've removed it and love the stock handling
adding all of the stuff up front evidently gave it more 'push' as i would of expected
Jul 21, 2009, 12:35 PM
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Thanks for the responses. Since then, I'm going to remove all the braces back to where it was.
I got 1.7 deg camber on the front, 1.1 deg in the back.
My spring rates are 12k front 10k rear - they are factory Ohlins rate. Ohlins said I got the early Road and Track kit that was made in Sweden. So the valving and rate are different than the current Road and Track kit.
I got 1.7 deg camber on the front, 1.1 deg in the back.
My spring rates are 12k front 10k rear - they are factory Ohlins rate. Ohlins said I got the early Road and Track kit that was made in Sweden. So the valving and rate are different than the current Road and Track kit.
Jul 21, 2009, 12:46 PM
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^ so there is your problem. Try flipping the springs around if they are the same diameter. You want the rear spring rate to be stiffer than the front in order for car to rotate better.
Jul 22, 2009, 01:39 PM
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No, no, no! Are you kidding? Swapping around the springs is going to make the understeering even worse!
Just to keep this simple and not going into pages of detail we can all do this Mythbusters style. Now I'm sure all you guys have Gran Turismo or Forza or some other racing simulator that you can change suspension settings on right? Most of the simulators noadays represent very closely what happens in the real world.
- Ok, First race your car (preferably an Evo) around a twisty turny technical track. The more turns on the track your racing on the easier to see results on smaller changes to the car's setup. Race around the track for at least 20 laps and record your best time.
- Go into suspension settings and lower the spring rate, compression and anti roll on the front of the car (usually at the same rate aggressively but not to the limits). Do the opposite to the rear of the car. Stiffen up everything on the rear. Go out and try to achieve a best time with this setup and record.
- Now go back into suspension setup and stiffen up the spring rate, compression and anti roll on the front of the car (aggressively from the default stettings). Do the opposite to the rear of the car. lossen up everything on the rear of the car. Go out and try to achieve a best time with this setup and record.
Let me know what your results are.
Just to keep this simple and not going into pages of detail we can all do this Mythbusters style. Now I'm sure all you guys have Gran Turismo or Forza or some other racing simulator that you can change suspension settings on right? Most of the simulators noadays represent very closely what happens in the real world.
- Ok, First race your car (preferably an Evo) around a twisty turny technical track. The more turns on the track your racing on the easier to see results on smaller changes to the car's setup. Race around the track for at least 20 laps and record your best time.
- Go into suspension settings and lower the spring rate, compression and anti roll on the front of the car (usually at the same rate aggressively but not to the limits). Do the opposite to the rear of the car. Stiffen up everything on the rear. Go out and try to achieve a best time with this setup and record.
- Now go back into suspension setup and stiffen up the spring rate, compression and anti roll on the front of the car (aggressively from the default stettings). Do the opposite to the rear of the car. lossen up everything on the rear of the car. Go out and try to achieve a best time with this setup and record.
Let me know what your results are.