Oversteer Understeer Balancing
04-18-2012 | 06:02 PM
#26
Thread Starter
Sucks Gas and Hauls Ass!
Joined: Apr 2010
Posts: 98
Likes: 0
From: SD
All the searching i have done on suspension as far as shocks go they are the best ones out there, so i have read. but yes i hope owners with the yellows installed could chime in.
04-18-2012 | 06:04 PM
#27
If you are only running 245 tires on the rear, just get 245 on the front which will give you the same tread width and with an alignment you should be able to get the car to be neutral with regards to oversteer. I had 255's on my 18x8 so they will easily fit.
04-18-2012 | 06:10 PM
#28
Yes the OP could do this, but I doubt anyone here would recommend it. Still doesn't fix the problem. Also a 245 on 8.5 wheels does not provide the same contact patch as 245 on 9.5 wheels.
04-18-2012 | 06:17 PM
#29
I know its not the same contact patch but it's close. I would have much wider tires if I had those wheels but that's just me. I guess it also depends on the wheel offset too, wider tires might not fit! Oh and that's what the S2000 guys do to get a square setup for Autocross
Last edited by wrightcomputing; 04-18-2012 at 06:20 PM.
04-19-2012 | 08:52 AM
#30
I know its not the same contact patch but it's close. I would have much wider tires if I had those wheels but that's just me. I guess it also depends on the wheel offset too, wider tires might not fit! Oh and that's what the S2000 guys do to get a square setup for Autocross
04-19-2012 | 09:11 AM
#31
Given what you say, it's really a no brainer to get *adjustable* sway bars front and rear as have been mentioned. As you want, you can adjust now for what you have and later for what you get. There is no downside to adjustable bars even on an otherwise stock suspension and they are not expensive. In your case, however you have a bastard suspension setup (oem shocks-shortened coils) which is the worst of combinations as oem shocks do not handle the limited spring travel well at all and extreme understeer (suspension travel is over) can easily result under sharp cornering loads.
One other take away that may be nice to know is that (anti-sway bar) use on street car and use on track car should be temepered by the effect they have on overall dynamics. Example, on street you really don't want terribly stiff bar anywhere front or back. Why? You couple both sides of the car together with stiff bars and loose some of the 'independence' of the independent suspension, IOW your overall ride quality will suffer, so keep it softer.
Alternatively, on track, ride quality is of no real importance, and at extreme suspension stresses a stiff roll bar setting (vs street setting) will help keep the suspension/car in a correct posture to perform best under extreme transitions conditions. That being said, if you start to enjoy tracking, a good set of coilovers will **correctly** allow some lowering, stiffen the overall suspension, and assist in reducing lean so that anti-roll bars are the 2nd, not 1st, line of prevention.
Balance in all suspension parts, not using just one component to much to fix any condition, and taking the time to find the **right** balance thru trial and error are most important. Good luck!
One other take away that may be nice to know is that (anti-sway bar) use on street car and use on track car should be temepered by the effect they have on overall dynamics. Example, on street you really don't want terribly stiff bar anywhere front or back. Why? You couple both sides of the car together with stiff bars and loose some of the 'independence' of the independent suspension, IOW your overall ride quality will suffer, so keep it softer.
Alternatively, on track, ride quality is of no real importance, and at extreme suspension stresses a stiff roll bar setting (vs street setting) will help keep the suspension/car in a correct posture to perform best under extreme transitions conditions. That being said, if you start to enjoy tracking, a good set of coilovers will **correctly** allow some lowering, stiffen the overall suspension, and assist in reducing lean so that anti-roll bars are the 2nd, not 1st, line of prevention.
Balance in all suspension parts, not using just one component to much to fix any condition, and taking the time to find the **right** balance thru trial and error are most important. Good luck!
Roll stiffness and vertical (spring) stiffness work together to control body roll. You can't discuss one without knowing where the other is. For example, I would not recommend a high roll stiffness with a low spring stiffness (lifting inside wheels). Spring stiffness affects both roll stiffness as well as pitch (and obviously vertical Z direction), where roll stiffness by bars will only affect roll stiffness. I am probably rambling here, so I will cut to the chase. Putting big bars on without coilovers could result in lifting inside wheels due to too much roll stiffness compared to spring stiffness. It is a ratio that needs to be balenced.
I think we have the same understanding since you stated that bars should be "reducing lean so that anti-roll bars are the 2nd, not 1st, line of prevention". This comes down to the ratio of roll stiffness/spring stiffness. There is a reason that road race cars generally run high spring rates and little or no bar.
04-19-2012 | 09:20 AM
#32
#50
Joined: Nov 2007
Posts: 7,521
Likes: 11
From: Caput Mundi
1 degree more negative in the front and what im looking to get in the end goal as far as suspension would be to eliminate as much body roll as possible and no understeer/oversteer. now i know i will eventually have to get squared tires for that but what i am thinking is i could try to find parts that would be adjusting, that way i could use them now and once i get squared away with the wheel situation i could adjust them then as well.
There's no need to fight bodyroll like an evil thing. Some roll is good and it's a street car you're talking about. This means it is always driven with tyres barely up to temp and on an extremely uneven surface.
Under these circumstances going stiffer is making the car handle worse. Even stiffer springs are a bad idea on an uneven surface.
Don't go around your problem: 225 or 245 wide rubbers all around on a non staggered setup are the first step. Then comes the rest according to the situation.
A neutral setup (little to no over\understeer) is mostly a matter of alignment after you get the right tyres.
04-19-2012 | 10:06 AM
#33
Momentum Keeps Me Going
Joined: Sep 2002
Posts: 5,036
Likes: 4
From: Colorado
JCrane, yes we are both understanding. AJ, perhaps this will help you. bse50 is so correct. Think of this. You want to reduce lean, so weld the shocks and brace weld springs solid - basically remove the suspension. 100% no lean!! Man we did it!!! We won right? Unfortunately, tte car would be nearly undriveable at any speed on any road.
"Leaning" is not a symptom to be limited to extinction, but a result of the suspension doing it's work. The suspension **needs** to lean to be able to sink the energy of the suspension. The difference is because....
1) A street suspension is designed with longer travel (more leaning) to benefit the comfort of the occupants and is designed to produce slower, lower frequency motions to provide comfort and safety on rough terrain and at street speeds.
A track suspension benefits from shorter travel (less leaning) to control of the car due to it receiving ultra high energy inputs and also needs to have fast dynamics (recovery) to maintain a higher frequency of operation under those condition on generally smooth surfaces and at high speeds where forces act quicker.
The goal (of the system as a whole, including ***spring / sways /bushing / unsprung weight*** is control of movement under the designed operation conditions. Balance is best, treat the suspension as a spring and damper equation, not pieces to be at odds with each others design.
"Leaning" is not a symptom to be limited to extinction, but a result of the suspension doing it's work. The suspension **needs** to lean to be able to sink the energy of the suspension. The difference is because....
1) A street suspension is designed with longer travel (more leaning) to benefit the comfort of the occupants and is designed to produce slower, lower frequency motions to provide comfort and safety on rough terrain and at street speeds.
A track suspension benefits from shorter travel (less leaning) to control of the car due to it receiving ultra high energy inputs and also needs to have fast dynamics (recovery) to maintain a higher frequency of operation under those condition on generally smooth surfaces and at high speeds where forces act quicker.
The goal (of the system as a whole, including ***spring / sways /bushing / unsprung weight*** is control of movement under the designed operation conditions. Balance is best, treat the suspension as a spring and damper equation, not pieces to be at odds with each others design.
04-19-2012 | 04:49 PM
#38
isnt your front rear tire diameter a little off?
is the understeer you speak off happening with the dsc on or off?
I ran the koni yellows and tein h springs with the bib rb bars for about 2 years. I was running hoosiers on track and have a little more power. The konis worked "OK" but when I switched to the kwV 3's it was a big noticeable difference. If I had to do it over again I wish i had saved my money from buying the springs/konis and had gotten the coilovers first.
My car also must be a little different from a lot of others-- as the big bars on the back really have not hurt me--i dont have a problem with oversteer-- IDK????
is the understeer you speak off happening with the dsc on or off?
I ran the koni yellows and tein h springs with the bib rb bars for about 2 years. I was running hoosiers on track and have a little more power. The konis worked "OK" but when I switched to the kwV 3's it was a big noticeable difference. If I had to do it over again I wish i had saved my money from buying the springs/konis and had gotten the coilovers first.
My car also must be a little different from a lot of others-- as the big bars on the back really have not hurt me--i dont have a problem with oversteer-- IDK????
Last edited by olddragger; 04-19-2012 at 04:58 PM.
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