Koni Shock settings Question
Thread Starter
Honda-Tech Member
Joined: Sep 2003
Posts: 277
Likes: 0
From: Portland OR
Koni Shock settings Question
Why does it seem like everyone sets the front shock's rebound to soft and the rear to stiff? I'm talking about OTS Konis.
It would make sense to me to set the front to stiff and the rear to soft. When you compress the front shocks, it would keep the front end down and all the weight up there. Having the rear soft would let the rear stay unloaded and would also help keep the weight on the front.
Maybe there's something I'm missing, but since the bump isn't adjustable, stiffening the rear wouldn't help it to rotate.
It would make sense to me to set the front to stiff and the rear to soft. When you compress the front shocks, it would keep the front end down and all the weight up there. Having the rear soft would let the rear stay unloaded and would also help keep the weight on the front.
Maybe there's something I'm missing, but since the bump isn't adjustable, stiffening the rear wouldn't help it to rotate.
Honda-Tech Member
Joined: Apr 2006
Posts: 486
Likes: 0
From: Portland, OR, USA
Re: Koni Shock settings Question (solo-x)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by solo-x »</TD></TR><TR><TD CLASS="quote">you're only thinking of one cornering phase. soft front rebound and stiff rear rebound will make the car looser on corner entry.</TD></TR></TABLE>
please explain further
please explain further
Honda-Tech Member
Joined: Mar 2000
Posts: 1,309
Likes: 0
From: Lancaster, PA, USA
Re: Koni Shock settings Question (pos_cd5)
Also, OTS Konis do not have enough rebound to keep a car jacked down after compression and you really don't want that anyway. Further, a front end that is lower than the rear end does not really have anymore weight on it than one that is same height. In other words the amount the springs are compressed is an indicator of weight loading not the cause of it.
People often have problems separating root causes from side effects. Another example is people's belief that big diameter wheels are faster than smaller diameter wheels. They base this on the fact that race cars have big wheels. But the only reason race cars have big wheels is to fit big brakes. The big wheel is a side effect of the big brake, but in itself the big wheel does not make a car faster. Actually it makes a car slower by adding weight and rotating mass as well as spreading the contact patch longitudinally rather than laterally.
regards,
alan
People often have problems separating root causes from side effects. Another example is people's belief that big diameter wheels are faster than smaller diameter wheels. They base this on the fact that race cars have big wheels. But the only reason race cars have big wheels is to fit big brakes. The big wheel is a side effect of the big brake, but in itself the big wheel does not make a car faster. Actually it makes a car slower by adding weight and rotating mass as well as spreading the contact patch longitudinally rather than laterally.
regards,
alan
Joined: Aug 2002
Posts: 217
Likes: 0
I've often wondered this myself. Wouldn't a soft front rebound cause the front of the car to "pop back up" after the initial compression on the outside during turn in? I can't imagine that this popping back up is good when you're still in the middle of the corner.
Thread Starter
Honda-Tech Member
Joined: Sep 2003
Posts: 277
Likes: 0
From: Portland OR
Re: (Burgh)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Burgh »</TD></TR><TR><TD CLASS="quote">I've often wondered this myself. Wouldn't a soft front rebound cause the front of the car to "pop back up" after the initial compression on the outside during turn in? I can't imagine that this popping back up is good when you're still in the middle of the corner. </TD></TR></TABLE>
This is exactly what I'm thinking
This is exactly what I'm thinking
Honda-Tech Member
Joined: Jun 2002
Posts: 3,569
Likes: 0
From: MA
Re: (DA9 Integra)
first, remember that shocks only control the rate of load transfer. they do nothing to change the amount.
second, remember that shocks only control the rate of load transfer when they are being compressed or extended due to outside forces on the chassis.
third, the shock with the highest velocity and/or the greatest displacement will have the biggest affect on handling balance.
in a corner that has the entry phase and braking phase overlapped, front rebound will do nothing. as you transition from the entry/braking phase to the mid corner phase, the inside front moves in extension. a lot of rebound force on that corner will take weight off that corner and put it on the outside front. that moves the car towards understeer.
of course, the above is a highly idealized scenario. a lot of other factors come into play that may change the result of a rebound change.
second, remember that shocks only control the rate of load transfer when they are being compressed or extended due to outside forces on the chassis.
third, the shock with the highest velocity and/or the greatest displacement will have the biggest affect on handling balance.
in a corner that has the entry phase and braking phase overlapped, front rebound will do nothing. as you transition from the entry/braking phase to the mid corner phase, the inside front moves in extension. a lot of rebound force on that corner will take weight off that corner and put it on the outside front. that moves the car towards understeer.
of course, the above is a highly idealized scenario. a lot of other factors come into play that may change the result of a rebound change.
Trending Topics
Honda-Tech Member
Joined: Jan 2003
Posts: 3,144
Likes: 3
From: Union, KY, USA
Re: (solo-x)
Remember also that you are unsing this as a tuning tool to effect the existing balance and handling charachteristics of a car, in these cases we are talking about an inherently understeeting car.
By taking the rear rebound to the higher end of the range and having the front at mid to lower end of the range (very rarely do you ever see a car best at full min front), you are having a greater effect on the overall roll stiffness differential front to rear so you will make the car turn better. Since the goal is to rotate the rear of a fwd car more at entry and rear rebound has it's most effect at corner entry then that is the tuning tool to use. Front shock tend to have more effect on corner exit as a generality but also can have some effect on the overall roll rate of the chassis. So some of more front rebound will work best as it will keep the chassis somewhat flatter but a bias of stiffness will help the car rotate ore at the rear.
I think if you try to isolate a single funtion or moment in a corner and apply it throughout, you are likely to talk yourself in circles and risk convincing yourself of things tthat may be limited actual effect.
By taking the rear rebound to the higher end of the range and having the front at mid to lower end of the range (very rarely do you ever see a car best at full min front), you are having a greater effect on the overall roll stiffness differential front to rear so you will make the car turn better. Since the goal is to rotate the rear of a fwd car more at entry and rear rebound has it's most effect at corner entry then that is the tuning tool to use. Front shock tend to have more effect on corner exit as a generality but also can have some effect on the overall roll rate of the chassis. So some of more front rebound will work best as it will keep the chassis somewhat flatter but a bias of stiffness will help the car rotate ore at the rear.
I think if you try to isolate a single funtion or moment in a corner and apply it throughout, you are likely to talk yourself in circles and risk convincing yourself of things tthat may be limited actual effect.
Honda-Tech Member
Joined: Jan 2000
Posts: 1,771
Likes: 1
From: Charlotte, NC, USA
Re: (solo-x)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by solo-x »</TD></TR><TR><TD CLASS="quote">first, remember that shocks only control the rate of load transfer. they do nothing to change the amount.
second, remember that shocks only control the rate of load transfer when they are being compressed or extended due to outside forces on the chassis.</TD></TR></TABLE>
Nate, I agree with you everywhere except that shocks will effect the distribution front/rear of weight transfer since they change the front and rear roll moment (during transient not SS). Like you said, they won't change the total amount...just the distribution across each axle during a transient phase.
I was going to recommend the Ortiz article but Nate already said the important parts.
second, remember that shocks only control the rate of load transfer when they are being compressed or extended due to outside forces on the chassis.</TD></TR></TABLE>
Nate, I agree with you everywhere except that shocks will effect the distribution front/rear of weight transfer since they change the front and rear roll moment (during transient not SS). Like you said, they won't change the total amount...just the distribution across each axle during a transient phase.
I was going to recommend the Ortiz article but Nate already said the important parts.
Joined: Aug 2002
Posts: 217
Likes: 0
Re: (GSpeedR)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GSpeedR »</TD></TR><TR><TD CLASS="quote">
I was going to recommend the Ortiz article but Nate already said the important parts.</TD></TR></TABLE>
Link please.
I was going to recommend the Ortiz article but Nate already said the important parts.</TD></TR></TABLE>
Link please.
Thread Starter
Honda-Tech Member
Joined: Sep 2003
Posts: 277
Likes: 0
From: Portland OR
Re: (CRX Lee)
But it seems to me that having stiff rebound in the rear would keep the rear end 'squatted' and a lot of weight back there. I could see how lots of rear bump valving would help rotation, but not lots of rebound.
But I'm focusing mainly on the outside shocks, not the inside. Maybe the inside shocks have more of an effect on handling than the outsides.
But I'm focusing mainly on the outside shocks, not the inside. Maybe the inside shocks have more of an effect on handling than the outsides.
Honda-Tech Member
Joined: Jan 2000
Posts: 1,771
Likes: 1
From: Charlotte, NC, USA
Re: (DA9 Integra)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DA9 Integra »</TD></TR><TR><TD CLASS="quote">But it seems to me that having stiff rebound in the rear would keep the rear end 'squatted' and a lot of weight back there. I could see how lots of rear bump valving would help rotation, but not lots of rebound.
But I'm focusing mainly on the outside shocks, not the inside. Maybe the inside shocks have more of an effect on handling than the outsides.</TD></TR></TABLE>
You don't want to confuse the movements of the chassis with weight transfer or weight distribution. In many cases they will be similar in direction and magnitude but often they are not.
You can't focus on just the outside shocks, since anytime the car rolls or pitches, all 4 shocks are doing something (on a normal independent suspension).
But I'm focusing mainly on the outside shocks, not the inside. Maybe the inside shocks have more of an effect on handling than the outsides.</TD></TR></TABLE>
You don't want to confuse the movements of the chassis with weight transfer or weight distribution. In many cases they will be similar in direction and magnitude but often they are not.
You can't focus on just the outside shocks, since anytime the car rolls or pitches, all 4 shocks are doing something (on a normal independent suspension).
Honda-Tech Member
Joined: Jan 2003
Posts: 3,144
Likes: 3
From: Union, KY, USA
Re: (DA9 Integra)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DA9 Integra »</TD></TR><TR><TD CLASS="quote"> I could see how lots of rear bump valving would help rotation, but not lots of rebound.</TD></TR></TABLE>
Rebound controls the sprung weight or transitional weight of the car and is used to effect the balance of the car. Compression or bump damping controls the unsprung weight or basically the tire's ability to be held to the ground. Use rebound only for balance and body motion, use bump to maximize the mechanical grip potential of the tire and the road surface. If you try to use bump to effect balance and not simply maximize the grip then you are chasing your tail and not using the tolls for what they really do.
Rebound controls the sprung weight or transitional weight of the car and is used to effect the balance of the car. Compression or bump damping controls the unsprung weight or basically the tire's ability to be held to the ground. Use rebound only for balance and body motion, use bump to maximize the mechanical grip potential of the tire and the road surface. If you try to use bump to effect balance and not simply maximize the grip then you are chasing your tail and not using the tolls for what they really do.
Honda-Tech Member
Joined: Jan 2003
Posts: 1,979
Likes: 0
From: Cogito ergo sum, Canada
Re: (CRX Lee)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX Lee »</TD></TR><TR><TD CLASS="quote">
Rebound controls the sprung weight or transitional weight of the car and is used to effect the balance of the car. Compression or bump damping controls the unsprung weight or basically the tire's ability to be held to the ground. Use rebound only for balance and body motion, use bump to maximize the mechanical grip potential of the tire and the road surface. If you try to use bump to effect balance and not simply maximize the grip then you are chasing your tail and not using the tolls for what they really do.</TD></TR></TABLE>
Assume you enter a corner on a smooth track with no bumps, and are turning right. The LF damper moves in bump, the RR damper moves in rebound, and the RF and LR dampers don't move much. Why would the bump adjustment on the left front damper not affect body motion control? If you stiffen the low speed bump, you get more weight transfer at the front, and thus move the car towards understeer. If you stiffen the rear low speed rebound, you get more weight transfer there and move the car towards oversteer. I don't see why the statement is always made about bump controlling only the unsprung weight when we are talking about handling and balance. If you have a damper that is not adjustable for low speed bump, then it cannot affect handling much, but for dampers with bump adjustments having an effect at velocities below say 50 mm/s (2 in./s), would that statement of bump adjustments only controlling the unsrpung weight be true? If that statement were true, why would manufacturers make dampers with 3 way and 4 way adjusters?
Rebound controls the sprung weight or transitional weight of the car and is used to effect the balance of the car. Compression or bump damping controls the unsprung weight or basically the tire's ability to be held to the ground. Use rebound only for balance and body motion, use bump to maximize the mechanical grip potential of the tire and the road surface. If you try to use bump to effect balance and not simply maximize the grip then you are chasing your tail and not using the tolls for what they really do.</TD></TR></TABLE>
Assume you enter a corner on a smooth track with no bumps, and are turning right. The LF damper moves in bump, the RR damper moves in rebound, and the RF and LR dampers don't move much. Why would the bump adjustment on the left front damper not affect body motion control? If you stiffen the low speed bump, you get more weight transfer at the front, and thus move the car towards understeer. If you stiffen the rear low speed rebound, you get more weight transfer there and move the car towards oversteer. I don't see why the statement is always made about bump controlling only the unsprung weight when we are talking about handling and balance. If you have a damper that is not adjustable for low speed bump, then it cannot affect handling much, but for dampers with bump adjustments having an effect at velocities below say 50 mm/s (2 in./s), would that statement of bump adjustments only controlling the unsrpung weight be true? If that statement were true, why would manufacturers make dampers with 3 way and 4 way adjusters?
Honda-Tech Member
Joined: Jan 2003
Posts: 1,979
Likes: 0
From: Cogito ergo sum, Canada
Re: (Burgh)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Burgh »</TD></TR><TR><TD CLASS="quote">
Link please. </TD></TR></TABLE>
http://www.auto-ware.com/ubbth...1#153
Link please.
</TD></TR></TABLE>http://www.auto-ware.com/ubbth...1#153
Honda-Tech Member
Joined: Jan 2000
Posts: 1,771
Likes: 1
From: Charlotte, NC, USA
Re: (descartesfool)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by descartesfool »</TD></TR><TR><TD CLASS="quote">Assume you enter a corner on a smooth track with no bumps, and are turning right. The LF damper moves in bump, the RR damper moves in rebound, and the RF and LR dampers don't move much. Why would the bump adjustment on the left front damper not affect body motion control? If you stiffen the low speed bump, you get more weight transfer at the front, and thus move the car towards understeer. If you stiffen the rear low speed rebound, you get more weight transfer there and move the car towards oversteer. I don't see why the statement is always made about bump controlling only the unsprung weight when we are talking about handling and balance. If you have a damper that is not adjustable for low speed bump, then it cannot affect handling much, but for dampers with bump adjustments having an effect at velocities below say 50 mm/s (2 in./s), would that statement of bump adjustments only controlling the unsrpung weight be true? If that statement were true, why would manufacturers make dampers with 3 way and 4 way adjusters?</TD></TR></TABLE>
The "rebound controls sprung mass; bump controls unsprung mass" is a rule of thumb used by shock companies to give a general ratio of rebound to bump. In terms of the actual dynamics which is a multi-body problem, it's not true. Every production shock company seems to use it, however.
The "rebound controls sprung mass; bump controls unsprung mass" is a rule of thumb used by shock companies to give a general ratio of rebound to bump. In terms of the actual dynamics which is a multi-body problem, it's not true. Every production shock company seems to use it, however.
Honda-Tech Member
Joined: Apr 2002
Posts: 18,961
Likes: 76
From: I am Tyson
Re: (GSpeedR)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GSpeedR »</TD></TR><TR><TD CLASS="quote">
The "rebound controls sprung mass; bump controls unsprung mass" is a rule of thumb used by shock companies to give a general ratio of rebound to bump. In terms of the actual dynamics, it's not true. Every production shock company will tell you this, however.</TD></TR></TABLE>
koni wont. (edit:about it NOT being true)
Modified by Tyson at 9:53 AM 6/15/2006
The "rebound controls sprung mass; bump controls unsprung mass" is a rule of thumb used by shock companies to give a general ratio of rebound to bump. In terms of the actual dynamics, it's not true. Every production shock company will tell you this, however.</TD></TR></TABLE>
koni wont. (edit:about it NOT being true)
Modified by Tyson at 9:53 AM 6/15/2006
Honda-Tech Member
Joined: Jan 2000
Posts: 1,771
Likes: 1
From: Charlotte, NC, USA
Re: (Tyson)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tyson »</TD></TR><TR><TD CLASS="quote">
koni wont.</TD></TR></TABLE>
Look 4 posts above.
I spoke with a Koni engineer a while ago while discussing tuning for my Yellows and I got the same rule. Heard the same thing while I worked for other companies.
koni wont.</TD></TR></TABLE>
Look 4 posts above.
I spoke with a Koni engineer a while ago while discussing tuning for my Yellows and I got the same rule. Heard the same thing while I worked for other companies.
Honda-Tech Member
Joined: Apr 2002
Posts: 18,961
Likes: 76
From: I am Tyson
Re: (GSpeedR)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GSpeedR »</TD></TR><TR><TD CLASS="quote">
In terms of the actual dynamics which is a multi-body problem, it's not true. Every production shock company seems to use it, however. </TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX Lee »</TD></TR><TR><TD CLASS="quote">
Rebound controls the sprung weight or transitional weight of the car and is used to effect the balance of the car. Compression or bump damping controls the unsprung weight or basically the tire's ability to be held to the ground. Use rebound only for balance and body motion, use bump to maximize the mechanical grip potential of the tire and the road surface. If you try to use bump to effect balance and not simply maximize the grip then you are chasing your tail and not using the tolls for what they really do.</TD></TR></TABLE>
sounds like koni is saying it IS true. and lee has come out and defended it as absolute truth.
In terms of the actual dynamics which is a multi-body problem, it's not true. Every production shock company seems to use it, however. </TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX Lee »</TD></TR><TR><TD CLASS="quote">
Rebound controls the sprung weight or transitional weight of the car and is used to effect the balance of the car. Compression or bump damping controls the unsprung weight or basically the tire's ability to be held to the ground. Use rebound only for balance and body motion, use bump to maximize the mechanical grip potential of the tire and the road surface. If you try to use bump to effect balance and not simply maximize the grip then you are chasing your tail and not using the tolls for what they really do.</TD></TR></TABLE>
sounds like koni is saying it IS true. and lee has come out and defended it as absolute truth.
Honda-Tech Member
Joined: Apr 2002
Posts: 18,961
Likes: 76
From: I am Tyson
Re: (Tyson)
here's what our buddy mark ortiz has to say.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chjkingme »</TD></TR><TR><TD CLASS="quote">Hmm, yeah. AGX's: definitely a Fawk no. As Lee(I think) recently mentioned, changing bump and rebound at the same time is something of a horrible experience. Well, maybe not horrible, but it sucks.</TD></TR></TABLE>
funny you mention that.
many of us here know who mark ortiz is, as the vehicle dynamics guru and publishes the back cover segment in Racecar Engineering magazine. in his April/May/June 2003 3 part article on "Shock and Spring Forces", he basically breaks down suspension in every response from position, to velocity, to "jerk" (the acceleration of acceleration) at each basic stage of turning (braking, turn in, middle, exit). the article prints out to be 13 pages. quite a long read. but its just that detailed, and yet he has to make a lot of simplifications. theres a thread with the link that i downloaded the article among many of his from. i printed it them all out and keep it near the crapper...
anyway, whats relevant is that at the VERY END of this 3 part article, he write this note. and im going to bother to type it all out because, well, i want to.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mark Ortiz »</TD></TR><TR><TD CLASS="quote">
Regarding whether to add or reduce damping on compression or extension, and at high velocited or low, some widely repeated advice would have us set compression damping to control sprung mass motion, and set extension damping to control unsprung mass motion. In my opinion, this is incorrect. At some time it may have served as simple advice to racers faced with setting the earliest double-adjustable shocks, but now we have revalaveable and four-way adjustable shocks, and reasonably good shock dynos. My advice nowadays is:
1) Use low-speed damping, in both extension and compression, to manage transient weight transfer and sprung mass motion. Do not expect this to work unless the surface is smooth enough so that sprung mass motion is the main cause of suspension movement. Use the springs and bars as your main means of managing weight transfer.
2) Use damping properties at velocities above 2 in/sec to manage sprung and unsprung mass behavior over road irregularites. Again, both compression and extension matter.
3) Keep compression and extension damping in reasonable proportion to each other. At most absolute velocities, extension damping should be at least a little stiffer than compression damping, but not more than twice as stiff and never more than three times as stiff unless you are deliberately trying to make the car jack down.
</TD></TR></TABLE>
i think mark ortiz' point is rather clear, and is contrary to what CRX Lee has been saying. now, i dont want to point out that Lee doesnt know what he's talking about. i dont think anyone could possibly take away his experience and knowledge. nor is my point to reflect anything negative about the success and customer satisfaction of koni products. I just want to add some other perspective on this topic. if i have taken anything out of context, then please forgive me.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chjkingme »</TD></TR><TR><TD CLASS="quote">Hmm, yeah. AGX's: definitely a Fawk no. As Lee(I think) recently mentioned, changing bump and rebound at the same time is something of a horrible experience. Well, maybe not horrible, but it sucks.</TD></TR></TABLE>
funny you mention that.
many of us here know who mark ortiz is, as the vehicle dynamics guru and publishes the back cover segment in Racecar Engineering magazine. in his April/May/June 2003 3 part article on "Shock and Spring Forces", he basically breaks down suspension in every response from position, to velocity, to "jerk" (the acceleration of acceleration) at each basic stage of turning (braking, turn in, middle, exit). the article prints out to be 13 pages. quite a long read. but its just that detailed, and yet he has to make a lot of simplifications. theres a thread with the link that i downloaded the article among many of his from. i printed it them all out and keep it near the crapper...
anyway, whats relevant is that at the VERY END of this 3 part article, he write this note. and im going to bother to type it all out because, well, i want to.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mark Ortiz »</TD></TR><TR><TD CLASS="quote">
Regarding whether to add or reduce damping on compression or extension, and at high velocited or low, some widely repeated advice would have us set compression damping to control sprung mass motion, and set extension damping to control unsprung mass motion. In my opinion, this is incorrect. At some time it may have served as simple advice to racers faced with setting the earliest double-adjustable shocks, but now we have revalaveable and four-way adjustable shocks, and reasonably good shock dynos. My advice nowadays is:
1) Use low-speed damping, in both extension and compression, to manage transient weight transfer and sprung mass motion. Do not expect this to work unless the surface is smooth enough so that sprung mass motion is the main cause of suspension movement. Use the springs and bars as your main means of managing weight transfer.
2) Use damping properties at velocities above 2 in/sec to manage sprung and unsprung mass behavior over road irregularites. Again, both compression and extension matter.
3) Keep compression and extension damping in reasonable proportion to each other. At most absolute velocities, extension damping should be at least a little stiffer than compression damping, but not more than twice as stiff and never more than three times as stiff unless you are deliberately trying to make the car jack down.
</TD></TR></TABLE>
i think mark ortiz' point is rather clear, and is contrary to what CRX Lee has been saying. now, i dont want to point out that Lee doesnt know what he's talking about. i dont think anyone could possibly take away his experience and knowledge. nor is my point to reflect anything negative about the success and customer satisfaction of koni products. I just want to add some other perspective on this topic. if i have taken anything out of context, then please forgive me.
Honda-Tech Member
Joined: Apr 2002
Posts: 18,961
Likes: 76
From: I am Tyson
Re: (Tyson)
and here's what crx lee has to say. not putting words in his mouth, but sounds to me like he's dismissing what ortiz has to say. (see paragraph 4)
btw, i experienced suspension jacking with koni yellows and stock springs very easily.
Originally Posted by CRX Lee
Actually his statement is not contrary to what I said. In fact, I have never heard anyone say "rebound for unsprung, compression for sprung" so I strongly wonder if he is does not have his information confused or an error was not caught in his writing or editting.
I have and will continue many times to say "rebound for sprung, compression for unsprung". I have no expereince where this does not work very well and lots of experience where it absolutely does. This is also consistant with the Koni philosophy that has been developed over 50+ years of international motorsports (by far and away the most successful damper company in the history of motorsports) and many more years of damper manufacturing. I do agree with many of Mr. Ortiz's comments about the lower speeds being induced by sprung weight body motion and the higher speeds typically being induced by road surface inputs and that can/should be taken into consideration. I would not by any means go so far at to say that 2 in/sec is the breakoff as there is a lot of information and context being left out or taken for granted. The basic motion ratio of the car and what the car is (F1 car, sports racer, production sedan, etc.) is vital but left out of a sweeping statement like this.
I don't know Mr. Ortiz or what his specific background is. I have read only a few of his articles as my copy of Racecar Engineering gets swiped from my mailbox on a regular basis by other folks in my office which is okay with me. I have had the opportunity to meet and talk with a number of people (a dozen or more) in the suspension, engine, tire and oil categories who have been put up on a pedestal as a guru by themselves or others. A number of them have written books and some write columns for magazines and papers. I have generally found some very interesting information from many of these people and I have also found some information that was very much wrong or at best taken out of a specific context or application and broadly applied to the greater realm which in fact it was incorrect for. I have found most to be very engaging people and a few to be amongst the most egotistical folks I have ever met. One in particular whom I call a friend is very interesting, experienced and chock full of great info but is so full of himself that I often say that he "just needs a good listening to". I have met several people who have written books that I don't think they really are fully qualified to state what they are saying as definitive fact by others. Guidance yes (or sometimes only maybe)... but not necessarily the final truth. These folks are simply (or hopefully) just regular people who have more experience, information or insight than their audience who are willing to share their info and should not necessarily be taken as the masters of final truth.
I think any time a person is put on a pedestal as a guru, some people want to bow down and absorb it as gospel and others want to take pot shots at them. I strongly believe that the best category is a third where an interested individual listens well and applies that person's information to fit his ideas into their own model of understanding and embraces the parts that make sense and work for them, stores the info that may not yet work for them and discards the chaff that they don't beleive. Experience and understanding are very valuable and are a great for learning and teaching but one must be careful or at least aware of where it comes from and how it is applied because there are many variables that can alter or void it. It is ultimately the listener's responsibility to learn and discern and he should be careful not to follow blindly.
PS- Any time "jacking down" gets mentioned, it goes right up my spine if it crosses over from the theoretical or at best extreme situation and gets applied to a real world situation or the broader model. I think far too many people talk about it and I have not seen in really happen in any real world situation. It would require the most extreme very, very softly sprung vehicle and a hideously overdamped situation that would be so greatly compromised that it should never be let get to that point. I had a high school teacher who used to use the word "piffle" for this kind of essentially non-reality.
Modified by CRX Lee at 7:17 AM 12/7/2005
I have and will continue many times to say "rebound for sprung, compression for unsprung". I have no expereince where this does not work very well and lots of experience where it absolutely does. This is also consistant with the Koni philosophy that has been developed over 50+ years of international motorsports (by far and away the most successful damper company in the history of motorsports) and many more years of damper manufacturing. I do agree with many of Mr. Ortiz's comments about the lower speeds being induced by sprung weight body motion and the higher speeds typically being induced by road surface inputs and that can/should be taken into consideration. I would not by any means go so far at to say that 2 in/sec is the breakoff as there is a lot of information and context being left out or taken for granted. The basic motion ratio of the car and what the car is (F1 car, sports racer, production sedan, etc.) is vital but left out of a sweeping statement like this.
I don't know Mr. Ortiz or what his specific background is. I have read only a few of his articles as my copy of Racecar Engineering gets swiped from my mailbox on a regular basis by other folks in my office which is okay with me. I have had the opportunity to meet and talk with a number of people (a dozen or more) in the suspension, engine, tire and oil categories who have been put up on a pedestal as a guru by themselves or others. A number of them have written books and some write columns for magazines and papers. I have generally found some very interesting information from many of these people and I have also found some information that was very much wrong or at best taken out of a specific context or application and broadly applied to the greater realm which in fact it was incorrect for. I have found most to be very engaging people and a few to be amongst the most egotistical folks I have ever met. One in particular whom I call a friend is very interesting, experienced and chock full of great info but is so full of himself that I often say that he "just needs a good listening to". I have met several people who have written books that I don't think they really are fully qualified to state what they are saying as definitive fact by others. Guidance yes (or sometimes only maybe)... but not necessarily the final truth. These folks are simply (or hopefully) just regular people who have more experience, information or insight than their audience who are willing to share their info and should not necessarily be taken as the masters of final truth.
I think any time a person is put on a pedestal as a guru, some people want to bow down and absorb it as gospel and others want to take pot shots at them. I strongly believe that the best category is a third where an interested individual listens well and applies that person's information to fit his ideas into their own model of understanding and embraces the parts that make sense and work for them, stores the info that may not yet work for them and discards the chaff that they don't beleive. Experience and understanding are very valuable and are a great for learning and teaching but one must be careful or at least aware of where it comes from and how it is applied because there are many variables that can alter or void it. It is ultimately the listener's responsibility to learn and discern and he should be careful not to follow blindly.
PS- Any time "jacking down" gets mentioned, it goes right up my spine if it crosses over from the theoretical or at best extreme situation and gets applied to a real world situation or the broader model. I think far too many people talk about it and I have not seen in really happen in any real world situation. It would require the most extreme very, very softly sprung vehicle and a hideously overdamped situation that would be so greatly compromised that it should never be let get to that point. I had a high school teacher who used to use the word "piffle" for this kind of essentially non-reality.
Modified by CRX Lee at 7:17 AM 12/7/2005
Honda-Tech Member
Joined: Jun 2002
Posts: 3,569
Likes: 0
From: MA
Re: (Tyson)
funny, i read what lee says and what mark says and i think they're both saying essentially the same thing.
as for ortiz and lee "disagreeing" on whether bump should be used to control sprung or unsprung mass, there are actually two rather distinct camps. there are a lot of damper manufacturers that use bump to control the sprung mass. AD, Moton, Penske are the ones I've seen that this seems to be true with based on shock dyno's i've seen. there is an equal amount that believe rebound should be used to control sprung mass. i beleive ortiz was addressing the first group, which has gained a lot of popularity as of late.
like gspeedr said though, real world dynamics place equal importance on both rebound and bump as they control both sprung and unsprung mass. you need only be concerned when there is a huge imbalance between the two forces.
nate
as for ortiz and lee "disagreeing" on whether bump should be used to control sprung or unsprung mass, there are actually two rather distinct camps. there are a lot of damper manufacturers that use bump to control the sprung mass. AD, Moton, Penske are the ones I've seen that this seems to be true with based on shock dyno's i've seen. there is an equal amount that believe rebound should be used to control sprung mass. i beleive ortiz was addressing the first group, which has gained a lot of popularity as of late.
like gspeedr said though, real world dynamics place equal importance on both rebound and bump as they control both sprung and unsprung mass. you need only be concerned when there is a huge imbalance between the two forces.
nate