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Old 05-27-2011 | 08:48 PM
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Originally Posted by mglobe
Hey all you navel gazers, how about answering BC's question?

Too many unknown variables exist to answer that one correctly with the info currently presented. Mid corner issue could be a spring issue as well as bar issue.
Old 05-27-2011 | 08:54 PM
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Originally Posted by onefastviking
Too many unknown variables exist to answer that one correctly with the info currently presented. Mid corner issue could be a spring issue as well as bar issue.
I honestly was thinking the same thing, but wanted someone more knowledgeable about setup issues to address the question. My limited understanding is that sway bars are a fine tuning tool, that should come into play after spring/damper rates have been optimized. Making a far reaching statement about sway bars and particular handling characteristics would likely be an unreliable answer at best.
Old 05-27-2011 | 09:01 PM
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Originally Posted by mglobe
I honestly was thinking the same thing, but wanted someone more knowledgeable about setup issues to address the question. My limited understanding is that sway bars are a fine tuning tool, that should come into play after spring/damper rates have been optimized. Making a far reaching statement about sway bars and particular handling characteristics would likely be an unreliable answer at best.
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Old 05-27-2011 | 09:02 PM
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Originally Posted by mglobe
Hey all you navel gazers, how about answering BC's question?



I have drive cars with very stiff rear bars and also no bar at all (not hooked up).

It seems to me that the scenario that resulted in surer grip mid corner was no rear bar, but the amount of feedback was reduced as to what the rear end was doing compared to the stiff rear bar (same car, same tires) I understand many people try and get stiffer bars for better turn in, but I personally know some racers who run no rear bar at all.

What say you?



A lot of times no rear bar will give you less rear end feel because you have a rear end that is behaving better. more rear bar doesnt really give better turn in, but can give the feeling of such because the rear can step out and rotate the the car. Softening the front, with a car that pushes (either with springs or with bar, can help turn in. as was said, there are so many factors, you just have to understand what they all primarily do and what they do in concert with the others as well. Lots of possiblities. Many times we cant change everything at once, so you need lots of track time to do it right (with lots of feeback to decide what the changes really did). you wouldnt be the first guy that changed a car in some way to be a handful, but was faster!
Old 05-27-2011 | 11:29 PM
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Originally Posted by mglobe
Hey all you navel gazers, how about answering BC's question?
Maybe recopy my post so it looks like I can spell. I edited it.
Old 05-28-2011 | 09:13 AM
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One thing to consider with rear grip issues is that it might be caused by too much rear roll and a softer sway could make it worse. If the front/rear roll couple is not even and the rear rolls over too much the car could loose it's camber or toe or both and the grip would "fall" away as the suspension compresses. I have been asked to drive cars with the complaint being rear grip and the rear bar going stiffer fixed the problem because it controlled the roll. When its a rear roll issue it normally happens after apex under hard power and the rear starts to loose grip toward the exit of the corner. If the car is doing a flat slide on corner exit at apex or just after throttle application then it might be too stiff a rear bar.
A driver needs to break down where in the corner the oversteer is happening and try to feel what the chassis is doing to help in deciding which way to make adjustments.
Old 05-28-2011 | 10:29 AM
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IMHO Cory nailed it. What I want to add is that suspensions are systems, and nothing works in a vacuum. Sometimes what is expected does not work because, like Cory explained, the symptoms are caused by a different problem, i.e. lack of rear grip caused by too high a spring rate (spring + sway bar) in which case a softer bar will help, or lack of rear grip caused by roll induced geometry change in which a stiffer bar will help. A thorough grasp of the symptoms is what will lead to a proper solution to the problem.

If this were easy, anyone could do it.
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Old 05-28-2011 | 10:50 AM
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Originally Posted by Larry Herman
IMHO Cory nailed it. What I want to add is that suspensions are systems, and nothing works in a vacuum. Sometimes what is expected does not work because, like Cory explained, the symptoms are caused by a different problem, i.e. lack of rear grip caused by too high a spring rate (spring + sway bar) in which case a softer bar will help, or lack of rear grip caused by roll induced geometry change in which a stiffer bar will help. A thorough grasp of the symptoms is what will lead to a proper solution to the problem.

If this were easy, anyone could do it.

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Larry,How many times have you told someone to try some change, just to have them look at you like you were crazy, but once they tried it and then when it worked they were amazed ?

It is a system, the whole car is a system !
Determining a solution doesn't just require a thorough grasp of the symptons but also an exactly moment the symptons occur and a knowledge and understanding of the sum of parts in which you are working with.
Old 05-28-2011 | 01:04 PM
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Folks, with my apologies to Viking, Bullitt and others, I have soft deleted posts which have taken this thread off track. It is not about the qualifications of any particular coach - Dave wanted it open to people who have experience, and it is HIS THREAD.

Let's keep it to asking and answering questions about teaching, driving techniques, car set up etc.

With a couple of notable and obvious exceptions, there was nothing wrong with the posts I have hidden except that they are off topic.

Thanks,
Old 05-28-2011 | 08:59 PM
  #220  
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Thanks, Bob
Old 05-28-2011 | 10:41 PM
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Ok, I've got a question about instructing. How do you deal with instructing in a platform you're not very familiar with? How essential is it in advancing your instructing skills to get seat time in platforms foreign to you? For me in particular, I seem to have a poorer sense of what front engine cars can and can not do.
Old 05-29-2011 | 01:53 AM
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I dunno, Mike, to me most modern production cars that we would see at a DE tend to be driven similarly. To me, the exceptions would be Vipers (ungodly amounts of wheelspinning torque & they tend to lift their nose aggressively under throttle). Heck, I drive your Spec 996 the exact same way I drive my M3: same amount of trail braking, same brake points, same turn in points, etc. the only thing different is the longer gearing in your car.
Old 05-29-2011 | 02:46 PM
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Originally Posted by Veloce Raptor
I dunno, Mike, to me most modern production cars that we would see at a DE tend to be driven similarly. To me, the exceptions would be Vipers (ungodly amounts of wheelspinning torque & they tend to lift their nose aggressively under throttle). Heck, I drive your Spec 996 the exact same way I drive my M3: same amount of trail braking, same brake points, same turn in points, etc. the only thing different is the longer gearing in your car.
Is that because they are so well balanced and suspension refinements? I know driving an earlier 911 is different than driving my 993. As well had a 2002 and t handeled differently than a 325i.
Old 05-29-2011 | 03:00 PM
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Originally Posted by FGL28
Is that because they are so well balanced and suspension refinements? I know driving an earlier 911 is different than driving my 993. As well had a 2002 and t handeled differently than a 325i.
IMO yes. Most modern cars we see at a DE (even with serious track modifications) will understeer, can be trail braked, benefit from a bit of left foot braking, etc. As an example: There are a lot of folks who to this day have trepidations about trailbraking a 996 or 997 GT3, when in fact they trail brake as well or even better than some of the cars that have "traditionally" benefitted from trailbraking (BMW's, etc.).

Yes you're right, a 1972 911 will probably not trailbrake as well as a 993...
Old 05-29-2011 | 03:17 PM
  #225  
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Originally Posted by Bob Rouleau
Folks, with my apologies to Viking, Bullitt and others, I have soft deleted posts which have taken this thread off track. It is not about the qualifications of any particular coach - Dave wanted it open to people who have experience, and it is HIS THREAD.

Let's keep it to asking and answering questions about teaching, driving techniques, car set up etc.

With a couple of notable and obvious exceptions, there was nothing wrong with the posts I have hidden except that they are off topic.

Thanks,
No worries Bob. Although I was kind of surprised to see Peter K.'s deleted also, his post seemed ok from what I can remember of it and he does have quite good information to add.
It's all good though.


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