Understeer question
05-04-2011, 06:42 AM
#11
6th Gear Member
Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
Cornering technique should come first, as that will affect what parts or tuning that you follow up with. Or maybe whether you even need to do anything at all. If you've ever played ball (or golf, for that matter), trying too hard to hit the long ball is lots more likely to end up with poor results than when you take just a little off of it and let the timing of your swing do the work. Maybe think of "overdriving" as being the motorsports equivalent of "overswinging".
Then play with the tire pressures a little.
A stiffer rear bar will reduce mid-corner understeer, and a sixxer will generally be a little more tolerant of too much rear bar than a GT would be. But it still won't be a lot of help if you've overdriven the fronts all the way into heavy/plowing/sliding understeer. Flip side is that it can make it a little harder to add throttle on corner exit - you won't be able to put quite as much power down until you're going straighter. If you're already on occasion getting the rear end loose with the throttle coming off the corners or getting RR wheelspin coming out of righthanders, a stiffer rear bar is going to be kind of a "be careful what you ask for" mod.
Norm
Then play with the tire pressures a little.
A stiffer rear bar will reduce mid-corner understeer, and a sixxer will generally be a little more tolerant of too much rear bar than a GT would be. But it still won't be a lot of help if you've overdriven the fronts all the way into heavy/plowing/sliding understeer. Flip side is that it can make it a little harder to add throttle on corner exit - you won't be able to put quite as much power down until you're going straighter. If you're already on occasion getting the rear end loose with the throttle coming off the corners or getting RR wheelspin coming out of righthanders, a stiffer rear bar is going to be kind of a "be careful what you ask for" mod.
Norm
05-04-2011, 07:52 AM
#12
4th Gear Member
Join Date: Dec 2007
Location: Ontario, Canada
Posts: 1,692
Norm
My track setup is per my sig and last season i was running 39 pounds front and rear in the NT01s.
The car feels pretty good to my somewhat less than sensitive posterior and generally I am happy with the handling. The one noticeable problem I have is a very slow speed right hander where the slow in out fast technique has helped reduce the oversteer and excessive wear on the left front.
The corner starts at about 1:00 in this video;
https://mustangforums.com/forum/s197...ml#post7532574
What would you suggest I try with the hot tire pressures allowing for the extra weight on the front of my SC.
My track setup is per my sig and last season i was running 39 pounds front and rear in the NT01s.
The car feels pretty good to my somewhat less than sensitive posterior and generally I am happy with the handling. The one noticeable problem I have is a very slow speed right hander where the slow in out fast technique has helped reduce the oversteer and excessive wear on the left front.
The corner starts at about 1:00 in this video;
https://mustangforums.com/forum/s197...ml#post7532574
What would you suggest I try with the hot tire pressures allowing for the extra weight on the front of my SC.
05-04-2011, 08:04 PM
#13
5th Gear Member
Thread Starter
Join Date: May 2010
Location: Ohio
Posts: 2,228
Cornering technique should come first, as that will affect what parts or tuning that you follow up with. Or maybe whether you even need to do anything at all. If you've ever played ball (or golf, for that matter), trying too hard to hit the long ball is lots more likely to end up with poor results than when you take just a little off of it and let the timing of your swing do the work. Maybe think of "overdriving" as being the motorsports equivalent of "overswinging".
Then play with the tire pressures a little.
A stiffer rear bar will reduce mid-corner understeer, and a sixxer will generally be a little more tolerant of too much rear bar than a GT would be. But it still won't be a lot of help if you've overdriven the fronts all the way into heavy/plowing/sliding understeer. Flip side is that it can make it a little harder to add throttle on corner exit - you won't be able to put quite as much power down until you're going straighter. If you're already on occasion getting the rear end loose with the throttle coming off the corners or getting RR wheelspin coming out of righthanders, a stiffer rear bar is going to be kind of a "be careful what you ask for" mod.
Norm
Then play with the tire pressures a little.
A stiffer rear bar will reduce mid-corner understeer, and a sixxer will generally be a little more tolerant of too much rear bar than a GT would be. But it still won't be a lot of help if you've overdriven the fronts all the way into heavy/plowing/sliding understeer. Flip side is that it can make it a little harder to add throttle on corner exit - you won't be able to put quite as much power down until you're going straighter. If you're already on occasion getting the rear end loose with the throttle coming off the corners or getting RR wheelspin coming out of righthanders, a stiffer rear bar is going to be kind of a "be careful what you ask for" mod.
Norm
It seems obvious to me that I should just go out an work on technique. That is all just fine I guess, because I would rather save my money for now.
So does anybody know how STR.Ts might affect cornering?
05-06-2011, 10:10 PM
#14
2nd Gear Member
Join Date: Aug 2007
Location:
Posts: 245
If the rear is slightly smaller, I'd definitely go for the GT bar. look for someone who is getting rid of the stock hardware after upgrading. Get stiffer bushings for the rear bar as well.
do your own alignment to make sure you are close to zero toe in the front. If you have no idea, go find some local auto-x guys. You can get a pretty darn accurate toe alignment by yourself. If you play with the camber, do that first.
Definitely play with tire pressures. If you are running normal tire pressures, increase the front in 2 psi steps. I'll bet 36ish would be great for grip.
05-10-2011, 03:51 PM
#15
1st Gear Member
Join Date: Sep 2008
Location: Arizona
Posts: 60
On the cheap:
If the rear is slightly smaller, I'd definitely go for the GT bar.
do your own alignment to make sure you are close to zero toe in the front. If you have no idea, go find some local auto-x guys. You can get a pretty darn accurate toe alignment by yourself. If you play with the camber, do that first.
Definitely play with tire pressures. If you are running normal tire pressures, increase the front in 2 psi steps. I'll bet 36ish would be great for grip.
If the rear is slightly smaller, I'd definitely go for the GT bar.
do your own alignment to make sure you are close to zero toe in the front. If you have no idea, go find some local auto-x guys. You can get a pretty darn accurate toe alignment by yourself. If you play with the camber, do that first.
Definitely play with tire pressures. If you are running normal tire pressures, increase the front in 2 psi steps. I'll bet 36ish would be great for grip.
Zero front toe = good. Make toe plates to set easily.
Tire pressures on stock Pirellis: I autocrossed on 42# front and rear; maybe not good for daily driving.
05-10-2011, 06:25 PM
#16
5th Gear Member
Thread Starter
Join Date: May 2010
Location: Ohio
Posts: 2,228
Would there be a benefit in going with a thicker rear sway then 20mm? If so, about how thick would a sway bar have to be before it started hurting performance?
05-13-2011, 12:36 PM
#17
6th Gear Member
Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
I'd get a 20mm GT take-off and drive around with it for a while - it's probably stiffer than you're thinking (it's about 50% stiffer than your 18mm Pony bar, not just the 10% or so that the diameter numbers might be suggesting to you).
Keep in mind that a neutral-ish setup that drives just fine on warm, dry roads can easily become "loose" when it's wet, cold, or worse. Since you mentioned not wanting to be twiddling with adjustments, you'll still want to retain some understeer for those conditions. Understeer has nothing on oversteer when it comes to suddenly getting your attention with visions of curbs, trees, utility poles, ditches, the end of the car that isn't connected to the steering wheel, hell, and handbaskets.
I would not expect the STRt's to shift the car's understeer/oversteer balance much (for that you'd look into staggered settings on the yellows). More like better composed and not quite as harsh especially in the rear. Get Sam Strano's thoughts.
Just happened to see something in the current issue of the SCCA's monthly magazine, written by the chief instructor for Bob Bondurant (and who has 27 years instructing experience at this point). "Easy in, fast out", with the thought that you ought to be able to start adding a tiny bit of throttle even before you get to the apex. A reasonable interpretation probably runs something like "If you can't do that every time on the street, you're doing something wrong".
Norm
Keep in mind that a neutral-ish setup that drives just fine on warm, dry roads can easily become "loose" when it's wet, cold, or worse. Since you mentioned not wanting to be twiddling with adjustments, you'll still want to retain some understeer for those conditions. Understeer has nothing on oversteer when it comes to suddenly getting your attention with visions of curbs, trees, utility poles, ditches, the end of the car that isn't connected to the steering wheel, hell, and handbaskets.
I would not expect the STRt's to shift the car's understeer/oversteer balance much (for that you'd look into staggered settings on the yellows). More like better composed and not quite as harsh especially in the rear. Get Sam Strano's thoughts.
Just happened to see something in the current issue of the SCCA's monthly magazine, written by the chief instructor for Bob Bondurant (and who has 27 years instructing experience at this point). "Easy in, fast out", with the thought that you ought to be able to start adding a tiny bit of throttle even before you get to the apex. A reasonable interpretation probably runs something like "If you can't do that every time on the street, you're doing something wrong".
Norm
Last edited by Norm Peterson; 05-13-2011 at 12:43 PM.
05-13-2011, 09:39 PM
#18
1st Gear Member
Join Date: Sep 2008
Location: Arizona
Posts: 60
Good Advice
Norm gives very good advice. You can take it to the bank.
I'd get a 20mm GT take-off and drive around with it for a while - it's probably stiffer than you're thinking (it's about 50% stiffer than your 18mm Pony bar, not just the 10% or so that the diameter numbers might be suggesting to you).
Keep in mind that a neutral-ish setup that drives just fine on warm, dry roads can easily become "loose" when it's wet, cold, or worse. Since you mentioned not wanting to be twiddling with adjustments, you'll still want to retain some understeer for those conditions. Understeer has nothing on oversteer when it comes to suddenly getting your attention with visions of curbs, trees, utility poles, ditches, the end of the car that isn't connected to the steering wheel, hell, and handbaskets.
I would not expect the STRt's to shift the car's understeer/oversteer balance much (for that you'd look into staggered settings on the yellows). More like better composed and not quite as harsh especially in the rear. Get Sam Strano's thoughts.
Just happened to see something in the current issue of the SCCA's monthly magazine, written by the chief instructor for Bob Bondurant (and who has 27 years instructing experience at this point). "Easy in, fast out", with the thought that you ought to be able to start adding a tiny bit of throttle even before you get to the apex. A reasonable interpretation probably runs something like "If you can't do that every time on the street, you're doing something wrong".
Norm
Keep in mind that a neutral-ish setup that drives just fine on warm, dry roads can easily become "loose" when it's wet, cold, or worse. Since you mentioned not wanting to be twiddling with adjustments, you'll still want to retain some understeer for those conditions. Understeer has nothing on oversteer when it comes to suddenly getting your attention with visions of curbs, trees, utility poles, ditches, the end of the car that isn't connected to the steering wheel, hell, and handbaskets.
I would not expect the STRt's to shift the car's understeer/oversteer balance much (for that you'd look into staggered settings on the yellows). More like better composed and not quite as harsh especially in the rear. Get Sam Strano's thoughts.
Just happened to see something in the current issue of the SCCA's monthly magazine, written by the chief instructor for Bob Bondurant (and who has 27 years instructing experience at this point). "Easy in, fast out", with the thought that you ought to be able to start adding a tiny bit of throttle even before you get to the apex. A reasonable interpretation probably runs something like "If you can't do that every time on the street, you're doing something wrong".
Norm
08-05-2012, 12:47 PM
#19
2nd Gear Member
Join Date: Sep 2010
Location: TX
Posts: 220
Sorry if I steep in.
I was reading this post, and I really see great knowledge about handling improvements. I have a future simillar issue. I have a GT Brembo with the Steeda Sport Springs and KONI STRT. My rear tires are almost wasted, and I was thinking if I could replace them with 275/35R19 or 275/40R19 on the stock brembo wheels. I think that this setup might bring understeer to my car, do you think that with a wider rear sway bar, this will bring back my car to a more neutral handling. I will like to improve the looks but without affecting the present handling, if posible it will be great to improve it.
Another doubt, is that, if you think that the car with the 3.73 gears (standard transmission) will behave strange with the 275/35R19 or 275/40R19, compared to the stock setup?
I was reading this post, and I really see great knowledge about handling improvements. I have a future simillar issue. I have a GT Brembo with the Steeda Sport Springs and KONI STRT. My rear tires are almost wasted, and I was thinking if I could replace them with 275/35R19 or 275/40R19 on the stock brembo wheels. I think that this setup might bring understeer to my car, do you think that with a wider rear sway bar, this will bring back my car to a more neutral handling. I will like to improve the looks but without affecting the present handling, if posible it will be great to improve it.
Another doubt, is that, if you think that the car with the 3.73 gears (standard transmission) will behave strange with the 275/35R19 or 275/40R19, compared to the stock setup?
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