Lets talk about c6(not a z06) suspension
#21
Le Mans Master
Originally Posted by shopdog
Other way round. A bigger front bar makes the rear loose. A bigger rear bar makes the front loose.
Sorry, wrong. A bigger front bar makes the car push more (understeer). A bigger rear bar makes the car oversteer.
#22
Originally Posted by jschindler
A bigger front bar adds understeer, a bigger rear bar adds oversteer.
The same holds true in reverse for the rear bar. If the car starts out neutral, stiffening the rear bar transfers weight to the unloaded inner rear tire allowing the rear to stick better, so the front breaks loose first, and you have understeer. So stiffening the rear bar makes the car tend to understeer.
Stiffening the bar at one end of the car makes the other end of the car looser (relatively speaking).
#24
Le Mans Master
Originally Posted by shopdog
Stiffening the bar at one end of the car makes the other end of the car looser (relatively speaking).
Here once the chassis develops any roll (like say while cornering) the inside front wheel will come up off the paved surface! Thereby, the inside front tire cannot possibly be delivering any traction to the front of the car while turning.
Thereby, stiffer front sway bars induce understeer.
#25
Team Owner
Originally Posted by shopdog
Nope. In a turn, a car's body rolls, transferring weight to the outside tire and unloading the inside tire. This reduces front end grip until at the limit the outside tire breaks away and you wind up going nose first into the weeds. This is understeer. A stiffer front antisway bar transfers weight from the outer tire to the inner tire, generating more total grip in the front and allowing the car to stay in the turn against a higher centrifugal force without the nose heading for the weeds. If the car was neutrally balanced to begin, the rear will now break loose first, and you have oversteer. So a stiffer front bar makes the car tend to oversteer.
The same holds true in reverse for the rear bar. If the car starts out neutral, stiffening the rear bar transfers weight to the unloaded inner rear tire allowing the rear to stick better, so the front breaks loose first, and you have understeer. So stiffening the rear bar makes the car tend to understeer.
Stiffening the bar at one end of the car makes the other end of the car looser (relatively speaking).
The same holds true in reverse for the rear bar. If the car starts out neutral, stiffening the rear bar transfers weight to the unloaded inner rear tire allowing the rear to stick better, so the front breaks loose first, and you have understeer. So stiffening the rear bar makes the car tend to understeer.
Stiffening the bar at one end of the car makes the other end of the car looser (relatively speaking).
#26
Originally Posted by jschindler
You seem to be alone in your thinking. I've been reading about suspensions as long as you have, and everything I have ever read contradicts your stance.
#27
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Originally Posted by 300cawd
but i want to learn to drive the car at limits before AH kicks in.
http://www.springmountainmotorsports.com
From the video, if you can't follow the line out of there, I can only imagine what it's like in the esses.
#28
Le Mans Master
Originally Posted by MitchAlsup
Consider an infinitely stiff front sway bar. A bar so stiff that both front tire always remain at the same ride height wrt the chassis.
Here once the chassis develops any roll (like say while cornering) the inside front wheel will come up off the paved surface! Thereby, the inside front tire cannot possibly be delivering any traction to the front of the car while turning.
Thereby, stiffer front sway bars induce understeer.
Here once the chassis develops any roll (like say while cornering) the inside front wheel will come up off the paved surface! Thereby, the inside front tire cannot possibly be delivering any traction to the front of the car while turning.
Thereby, stiffer front sway bars induce understeer.
#29
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Originally Posted by shopdog
Nope. In a turn, a car's body rolls, transferring weight to the outside tire and unloading the inside tire. This reduces front end grip until at the limit the outside tire breaks away and you wind up going nose first into the weeds. This is understeer. A stiffer front antisway bar transfers weight from the outer tire to the inner tire, generating more total grip in the front and allowing the car to stay in the turn against a higher centrifugal force without the nose heading for the weeds. If the car was neutrally balanced to begin, the rear will now break loose first, and you have oversteer. So a stiffer front bar makes the car tend to oversteer.
The same holds true in reverse for the rear bar. If the car starts out neutral, stiffening the rear bar transfers weight to the unloaded inner rear tire allowing the rear to stick better, so the front breaks loose first, and you have understeer. So stiffening the rear bar makes the car tend to understeer.
Stiffening the bar at one end of the car makes the other end of the car looser (relatively speaking).
The same holds true in reverse for the rear bar. If the car starts out neutral, stiffening the rear bar transfers weight to the unloaded inner rear tire allowing the rear to stick better, so the front breaks loose first, and you have understeer. So stiffening the rear bar makes the car tend to understeer.
Stiffening the bar at one end of the car makes the other end of the car looser (relatively speaking).
http://www.circletrack.com/techartic...n_brake_setup/
http://www.racelinecentral.com/RacingSetupGuide.html
http://www.240edge.com/performance/tuning-bars.html
http://www.whiteline.com.au/default..../faqelse01.htm
#30
Originally Posted by MitchAlsup
Consider an infinitely stiff front sway bar. A bar so stiff that both front tire always remain at the same ride height wrt the chassis.
Here once the chassis develops any roll (like say while cornering) the inside front wheel will come up off the paved surface! Thereby, the inside front tire cannot possibly be delivering any traction to the front of the car while turning.
Thereby, stiffer front sway bars induce understeer.
Here once the chassis develops any roll (like say while cornering) the inside front wheel will come up off the paved surface! Thereby, the inside front tire cannot possibly be delivering any traction to the front of the car while turning.
Thereby, stiffer front sway bars induce understeer.
The answer is no they are not, and the reason why is that you're thinking about the problem the wrong way. What you're missing is that the antisway bars tie together the unsprung weight of the car, but not the sprung weight of the car. The total lateral friction force of an unloaded tire is less than that of one which is loaded. F=kW/A So if the sprung weight (the vast majority of the weight of the car) rolls away from the inner tire, it loses traction. What the antisway bar does is transfer some of that weight back to the inner, allowing it to grip better. The stiffer the bar, the greater the weight transfer. In the limit case with the bar being infinitely stiff, half of the sprung weight will be transferred to the inner tire. This is ideal because the inner and the outer tires will now have equal grip, and the car will corner as hard as possible before the tires break loose and let it slide.
Of course the ride would be horrible on a bumpy surface in that case because if one wheel encounters a bump, the other would feel it equally, thus defeating the purpose of independent suspension. So they don't make the antisway bars infinitely stiff. But at least on a smooth surface, infinitely stiff bars would be ideal, and on rougher than perfect surfaces, you still want to make the bars as stiff as is compatible with keeping the car from bouncing into the air over bumps.
Last edited by shopdog; 08-25-2006 at 07:20 PM.
#31
Originally Posted by glennhl
Sorry, wrong. A bigger front bar makes the car push more (understeer). A bigger rear bar makes the car oversteer.
Originally Posted by C6400hp
I've never said this before and probably never will again but, YOU ARE WRONG. Please forgive me Shopdog you must be having a brain fart today
Originally Posted by C6400hp
..... Please forgive me Shopdog you must be having a brain fart today
http://www.circletrack.com/techartic...n_brake_setup/
http://www.racelinecentral.com/RacingSetupGuide.html
http://www.240edge.com/performance/tuning-bars.html
http://www.whiteline.com.au/default..../faqelse01.htm
http://www.circletrack.com/techartic...n_brake_setup/
http://www.racelinecentral.com/RacingSetupGuide.html
http://www.240edge.com/performance/tuning-bars.html
http://www.whiteline.com.au/default..../faqelse01.htm
Last edited by '06 Quicksilver Z06; 08-25-2006 at 07:38 PM.
#32
Melting Slicks
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Originally Posted by shopdog
So, if we're to believe your theory, the softer the antisway bars, the better a car would corner. At the limit, no bars at all would corner best. Hmmm, wonder why Chevy puts bigger bars on its "sportier" packages then. Are they trying to limit the cornering ability of the Z51 and Z06 to less than that of the base suspension?
The answer is no they are not, and the reason why is that you're thinking about the problem the wrong way. What you're missing is that the antisway bars tie together the unsprung weight of the car, but not the sprung weight of the car. The total lateral friction force of an unloaded tire is less than that of one which is loaded. F=kW/A So if the sprung weight (the vast majority of the weight of the car) rolls away from the inner tire, it loses traction. What the antisway bar does is transfer some of that weight back to the inner, allowing it to grip better. The stiffer the bar, the greater the weight transfer. In the limit case with the bar being infinitely stiff, half of the sprung weight will be transferred to the inner tire. This is ideal because the inner and the outer tires will now have equal grip, and the car will corner as hard as possible before the tires break loose and let it slide.
Of course the ride would be horrible on a bumpy surface in that case because if one wheel encounters a bump, the other would feel it equally, thus defeating the purpose of independent suspension. So they don't make the antisway bars infinitely stiff. But at least on a smooth surface, infinitely stiff bars would be ideal, and on rougher than perfect surfaces, you still want to make the bars as stiff as is compatible with keeping the car from bouncing into the air over bumps.
The answer is no they are not, and the reason why is that you're thinking about the problem the wrong way. What you're missing is that the antisway bars tie together the unsprung weight of the car, but not the sprung weight of the car. The total lateral friction force of an unloaded tire is less than that of one which is loaded. F=kW/A So if the sprung weight (the vast majority of the weight of the car) rolls away from the inner tire, it loses traction. What the antisway bar does is transfer some of that weight back to the inner, allowing it to grip better. The stiffer the bar, the greater the weight transfer. In the limit case with the bar being infinitely stiff, half of the sprung weight will be transferred to the inner tire. This is ideal because the inner and the outer tires will now have equal grip, and the car will corner as hard as possible before the tires break loose and let it slide.
Of course the ride would be horrible on a bumpy surface in that case because if one wheel encounters a bump, the other would feel it equally, thus defeating the purpose of independent suspension. So they don't make the antisway bars infinitely stiff. But at least on a smooth surface, infinitely stiff bars would be ideal, and on rougher than perfect surfaces, you still want to make the bars as stiff as is compatible with keeping the car from bouncing into the air over bumps.
Get a copy of "Tune to Win" by Caroll Smith.
#33
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Originally Posted by shopdog
In the limit case with the bar being infinitely stiff, half of the sprung weight will be transferred to the inner tire.
#34
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Originally Posted by shopdog
So, if we're to believe your theory, the softer the antisway bars, the better a car would corner. At the limit, no bars at all would corner best. Hmmm, wonder why Chevy puts bigger bars on its "sportier" packages then. Are they trying to limit the cornering ability of the Z51 and Z06 to less than that of the base suspension?
The answer is no they are not, and the reason why is that you're thinking about the problem the wrong way. What you're missing is that the antisway bars tie together the unsprung weight of the car, but not the sprung weight of the car. The total lateral friction force of an unloaded tire is less than that of one which is loaded. F=kW/A So if the sprung weight (the vast majority of the weight of the car) rolls away from the inner tire, it loses traction. What the antisway bar does is transfer some of that weight back to the inner, allowing it to grip better. The stiffer the bar, the greater the weight transfer. In the limit case with the bar being infinitely stiff, half of the sprung weight will be transferred to the inner tire. This is ideal because the inner and the outer tires will now have equal grip, and the car will corner as hard as possible before the tires break loose and let it slide.
Of course the ride would be horrible on a bumpy surface in that case because if one wheel encounters a bump, the other would feel it equally, thus defeating the purpose of independent suspension. So they don't make the antisway bars infinitely stiff. But at least on a smooth surface, infinitely stiff bars would be ideal, and on rougher than perfect surfaces, you still want to make the bars as stiff as is compatible with keeping the car from bouncing into the air over bumps.
The answer is no they are not, and the reason why is that you're thinking about the problem the wrong way. What you're missing is that the antisway bars tie together the unsprung weight of the car, but not the sprung weight of the car. The total lateral friction force of an unloaded tire is less than that of one which is loaded. F=kW/A So if the sprung weight (the vast majority of the weight of the car) rolls away from the inner tire, it loses traction. What the antisway bar does is transfer some of that weight back to the inner, allowing it to grip better. The stiffer the bar, the greater the weight transfer. In the limit case with the bar being infinitely stiff, half of the sprung weight will be transferred to the inner tire. This is ideal because the inner and the outer tires will now have equal grip, and the car will corner as hard as possible before the tires break loose and let it slide.
Of course the ride would be horrible on a bumpy surface in that case because if one wheel encounters a bump, the other would feel it equally, thus defeating the purpose of independent suspension. So they don't make the antisway bars infinitely stiff. But at least on a smooth surface, infinitely stiff bars would be ideal, and on rougher than perfect surfaces, you still want to make the bars as stiff as is compatible with keeping the car from bouncing into the air over bumps.
If a car is turning right the body rolls left. The spring compresses. The sway bar wants to follow it up. On the right side the suspension extends. The sway bar tries to counter this and transfers load away from the tire, not to it. All else being equal, the no sway bar would offer the most grip. The problem is that at a certain point the car rolls enough that the center of gravity raises. The other issue is that the further the car rolls the longer it takes so transient response suffers.
Thus sway bars should be at the happy medium wher the car generates the most grip while losing the least CG and maintaining the best transient response.
#35
Team Owner
Originally Posted by C6400hp
I've never said this before and probably never will again but, YOU ARE WRONG. Please forgive me Shopdog you must be having a brain fart today
http://www.circletrack.com/techartic...n_brake_setup/
http://www.racelinecentral.com/RacingSetupGuide.html
http://www.240edge.com/performance/tuning-bars.html
http://www.whiteline.com.au/default..../faqelse01.htm
http://www.circletrack.com/techartic...n_brake_setup/
http://www.racelinecentral.com/RacingSetupGuide.html
http://www.240edge.com/performance/tuning-bars.html
http://www.whiteline.com.au/default..../faqelse01.htm
#36
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As to the original poster, Corvettes, like pretty much all street cars, understeer. If the car oversteers unintentionally you are doing something wrong. Your video is too short to tell, but if I had to guess I'd bet you have corner entry understeer that is turning into corner exit oversteer. In other words, in the early part of the corner you are turning the wheel too far. the fronts are scrubbing. as the car scrubs speed passing mid corner the fronts get better grip. Now you are getting on the power but your steering wheel is turned too far. The rears loose some of their lateral ability because they are now trying to accelerate the car as well. That's when the rear steps out. No matter what, you are not hitting "track out" on your video. You need to unwind the wheel more coming out of the turn. The best thing you could do is spend your money on some instruction. It will make way more difference than any suspension parts you are going to buy.
#37
Melting Slicks
On IRS cars such as a Vette stiffening the front bar will lessen under steer. What may be causing some of the confusion in this thread is that on some live axle cars the opposite is true ie. over steer increases. This is not true on all live axle cars but it does happen on some depending on where you are starting from.
BTW all street cars by design under steer as this is a much safer condition for the average driver. It's probably a safer condition for most race cars by not always the fastest way around the course depending on what the course is.
BTW all street cars by design under steer as this is a much safer condition for the average driver. It's probably a safer condition for most race cars by not always the fastest way around the course depending on what the course is.
#38
Team Owner
Originally Posted by ronsc1985
On IRS cars such as a Vette stiffening the front bar will lessen under steer. What may be causing some of the confusion in this thread is that on some live axle cars the opposite is true ie. over steer increases. This is not true on all live axle cars but it does happen on some depending on where you are starting from.
BTW all street cars by design under steer as this is a much safer condition for the average driver. It's probably a safer condition for most race cars by not always the fastest way around the course depending on what the course is.
BTW all street cars by design under steer as this is a much safer condition for the average driver. It's probably a safer condition for most race cars by not always the fastest way around the course depending on what the course is.
#39
Originally Posted by jschindler
I dissagree with that as well. Makes no difference whether it is IRS or solid axle. Bigger bars on front increase understeer, bigger on back increases oversteer.
There are already reports here of people going to the larger Z06 rear sway bar and keeping the existing front Z51 sway bar and ending up with more oversteer.
Its part of why I won't put a Z06 rear sway bar on my own car. I have experience enough oversteer as it is when I autocross the car.
I thought it was common knowledge that bigger front bars increase push/understeer, and bigger rear bars increase oversteer.
Last edited by '06 Quicksilver Z06; 08-25-2006 at 11:04 PM.
#40
Melting Slicks
Originally Posted by jschindler
I dissagree with that as well. Makes no difference whether it is IRS or solid axle. Bigger bars on front increase understeer, bigger on back increases oversteer.