I don't intent to hide it, I post link to the article I use. And I don't see what make an automotive damper so special, it still work the same way as other damper do, dampen vibration. So even building damper pricipal still can be used.
Both has the same graph. It's not wrong, why it should be misleading?
Really well lets have a look at that shall we. First I have already agreed that the basic principals are the same, so do not try and make out otherwise. Secondly if mass-dampers are no different to normal automotive dampers would you care to explain why Renault’s Formula One team was banned from using a mass damper in its car this season? The mass damper was not being used by them as a replacement for the standard dampers, rather to assist in the reduction of vibration and disruption to the car, to aid the aerodynamic balance and characteristics of the car. The FIA banned it for being a ‘moveable aerodynamic device’, had it been considered a true suspension component it would not have been banned.
The basic principals of the two are similar (as I have repeatedly said), but they are not directly interchangeable, to present one as the other without clearly stating so is miss-leading.
It's obvious that you have difficulty reading graph, and somehow I doubt you can make one. Try to make graph out of what you post.
If you don't want to do this bellow, fine, I don't want your head blow because of this.
Suchayo at what part of this do you want to stop with the personal digs and near insults, before or after you get an infraction for it?
Am I going to draw your graphs and diagrams? No, the reason being as you will read below I have quite honestly had enough of this messing around, I’m beginning to reach the point were I thing either you are incapable of understanding what I am saying or you are deliberately trying to manipulate what I have said in a manner that was never intended. I have explained and re-explained these things over the course of the last year; the only person who has failed to grasp them is you. The common factor here is quite simply
you, its seems to me that when you have failed to grasp what is said to you (by members here or from source material) you resort to re-wording things or simply insulting people.
BTW, I forgot about the Italic part, "However as the total load transfer will take a fixed amount of time", from what source do you get this?
Soft damper and stiff damper has the same amount of total load transfer time? Damper can not change the total load transfer time then? Aren't you fogetting this Skip Barber quote:
"A stiffer bump setting slows down the motion on its corner and speeds up the load transfer"
And you seem to be forgetting this…
Scaff
"Now the above is a very, very simple look at how this works (its actually not 100% accurate either as load transfer is occurring ‘through’ the damper when its not reacting – but it does help ‘visualise’
."
…which must be a bit embarrassing for you, as you did quote it back to me as well.
and still dive after that.
Yes, I don’t believe I said it would stop all dive, nor did the quote I gave.
No, it does not react slowly, but it move slowly. Try to learn to read the graph Scaff. Horizontal line in time vs movement graph mean thing do not move over time, vertical line mean thing move in a single time. late reaction would show as a horizontal line followed by curve. While slow movement show as low angle diagonal line.
I said “react physical” meaning movement, so rather than (once again) trying the cheap insults its you that should read things a little more carefully.
Look at the left top corner of the graph:
At about 0.1 x axis you should see that all three damper stifness curve collide. It means Scaff, at 0.1 second or something all three damper stiffness move at the same speed, at the same distance. This means all three damper stiffness have the same reaction time, since all three of them already react and move at the same manner.
and when Skip Barber says: "slows down the motion" (stiff damper) it does not mean "slows down the reaction".
when Skip Barber says: “allows the suspension to move faster” (soft damper) it does not mean “allows the suspension to react faster”.
So Sucahyo does only the first 0.1 second of the graph count? If so why.
Looking at that graph (and working with X = Time and Y = Distance moved – most likely damper shaft) the lines do not converge (collide) at 0.1 seconds, they diverge (separate). The only way you could possibly say they are colliding or converging is if you were to be reading the graph backwards, but that would mean that time (x-axis) would be going backwards (from 4 seconds to zero) which is not very likely.
Looking at the movement starting at “1” and calculating the time taken to reach “0.2” on the y=axis differs for each line.
Green (under-damped) = 0.45 seconds (approx)
Red (critically damped) = 0.75 seconds (approx)
Blue (over-damped) = 1.15 seconds (approx)
So the time taken to move the same ‘distance’ increases as damper stiffness increases, and I have not said otherwise.
Or we could look at it in terms of distance travelled in 1 second (distance of what is not clear as neither of the axis on the graph is actually labelled and you have not been clear about what the y-axis is actually the movement of or the units of scale in place).
Green (under-damped) = 5 units of movement (approx), from 1 to -3.5 and then back up to -3.0
Red (critically damped) = 0.95 units of movement (approx), from 1 to 0.05
Blue (over-damped) = 0.75 units of movement (approx), from 1 to 0.25
So quite clearly the stiffer the damper the less distance travelled in a set period of time, which exactly matches what we see with higher value dampers in the Caterham Stright-line brake test.
I think that it’s also very important to note that the graph you have used is based on purely mathematical modelling of the Critical Damping Co-efficient and it not taken from actual shock dyno plotting. I’ve already quoted a few sources on how this does not always translate into how a car will exactly react or feel on track. What we are looking at here is how the theory works, which is why I also posted the following, which you seem to have not read.
Race & Rally Car Source Book P.75
One very big advantage of a damper that can be altered separately on bump is that it can be used as an anti-dive or anti-squat device. This is because for a very short interval after loads are fed into the suspension, the car 'feels' a hard damper as almost solid.
About stiffer damper will increase body roll when inside tire meet bump:
The link do not describe how car body react when the inside tire meet bump. It explain how car body react during cornering.
Which is great if we were discussing body roll (or more specifically from the paper in question vehicle roll-pover), but that’s not what you were claiming. You said that
sucahyo
Stiffer dampers and springs will cause more body roll:
- when the inside tire hit bump, yes
- When the inside tire do not hit any bump, no, the opposite.
The above does not discuss this at all, and as such does not support your claim at all. Not only that but it discusses a single vehicle with fixed damper and spring rates, it does not address changes in damper and spring rates and there effects at all.
When the car do cornering, the corner inside damper and spring force will pull the car body while the outside damper and spring force will push the car body. When the inside tire meet bump, the bump will create force. Damper and spring will try to resist and absorb the force, this will create force that push the car body. This can change the current force direction of inside force, from pull to push. This will increase car roll.
First of all what part of the corner? Entry, exit or constant radius?
As you do not discuss front or rear separately lets assume its constant radius, well first off the inside suspension will be in low-speed rebound (load is/has been transferred off the suspension and it is reacting to this) and the outside suspension will be in low-speed bound (load is/has been transferred onto the suspension and its reacting to this). The body roll (from inside to the outside) has been caused by the load transfer.
Should one or both of the inside tyres now hit a curb it will almost certainly be in the high-speed damping area (normally classed as damper shaft velocities above 1 inch/second – source Penske) and more importantly this move into bound is caused not by the movement of the sprung mass (roughly the car body), but rather the un-sprung mass (wheel, tyre and all un-sprung suspension components).
Your own explanation of this totally fails to differentiate between suspension forces caused by two differencing sources (sprung and un-sprung) and the differing damper reactions that can occur as a result (lo and high speed damping).
I mean my post far back, like:
"
Your test result is about the same as mine although with much more greater detail , but the conclusion is different. IMO, more jump and vibration can be caused by softer damper. Stiffer damper will prevent jumping and vibrating better."
"
d-low jump more in grass, d-high jump more in tarmac.
d-low vibrate slower in grass, d-high vibrate more in grass.
d-low never vibrate in tarmac, d-high sometimes vibrate in tarmac."
I don't think jump visual in GT4 is an error, and I don't believe vibration in GT4 is an error too.
The problem with this is quite simply that it is not supported by any outside source; every single one quoted disagrees with you. In fact they directly contradict you.
Scaff
The following is taken from a Penske Technical Manual.
Compression
The idea is to set the compression damping forces to suit the bumps in critical areas, such as corners, corner exits and braking zones.
Increasing or lowering cannister pressure (range 150 to 300psi) can have an influence on support under braking, acceleration, and tyre loading on turn-in, and mid-corner grip.
Step 1 -Set the rebound adjuster to full soft.
Step 2 -Starting with the compression set at full soft, drive a lap then return to increase the bump settings. Continue this process of adding bump control to minimize the upsets until the car becomes harsh, loses tyre compliance and traction. At this point you know that you have gone to far on the compression settings; back off one click.
Rebound
The idea is to tighten up the car; stabilise the platform and eliminate the floating 'Cadillac feeling'. It will also reduce the rate of body roll.
Step 1-With the rebound setting at full soft, add five flats or clicks of rebound adjustment at a time, then continue the process until the car becomes skittish or the rear wheels hop under braking. At this point you know you have gone to far on the rebound side, back off one flat or click at a time for the final balance.
or we could take a look at Allan Stainforth (from Race and Rally car source book).
Bounce, wallow, lurch into corners - too little rebound damping.
Car jacks itself onto the bumpstops because the coil is too weak to fight against the damper - too much rebound damping.
Grounding, lurch onto the front or rear corner, excessive squat or nose diving - too little bump damping
Very hard ride, wheel hop sideways in corner - too much bump damping.
Now both of those quite clear say that an increase in harshness, skittish behaviour and hard ride are a result of an increase in damping.
And
Stasis Engineering
Q: Won't high spring rates make the ride harsh?
A: No. The primary function of the spring is to control the roll of the vehicle. Body roll, brake dive and acceleration squat are all functions of spring rate. By increasing the rate of the spring, you decrease the movement of the body. Ride compliance and harshness are more a function of high speed damper compression resistance than spring rate
And this, first posted by myself over a year ago
Skip Barber
Expect that the shock settings for bumpy racetracks will have to be softer in order to allow the suspension to move fast enough to keep the tyres in contact with the track surface.
These have all been posted multiple times now and you seem to ignore, dismiss or re-word them to try and suit your own beliefs. The simple point of fact is they contradict what you are saying.
.
Softer damper make suspension move in a longer time, this is what we see as late reaction in your caterham and range storm test. Stiffer damper stop supension movement quicker, show as faster reaction, faster roll, faster braking, non jelly reaction, etc.
No, no, no.
The quotes I have provided above and on numerous occasions do not support what you are saying here. Allan Staniforth quite clearly says that stiff/hard damper can be ‘felt’ as almost solid when load is applied, showing that a tiny delay in any visible movement is a characteristic of stiffer dampers. In addition the graph you posted above shows that over the same time period and for the same load a stiffer damper will move ‘less’ than a softer damper (under-damped vs critical damping vs over-damped).
Your explanation does not even match your own sources.
This and experience riding harsh ride on a car with damper too soft:
First off Sucahyo your own real world experience of a wide range of cars on a wide range of surfaces, but in particular very stiff set-ups on smooth track surfaces, is by your own admission limited.
Secondly you have failed time and time again to show any proof of experiencing a harsher ride (uncomfortable maybe) on softer dampers. Yet I have provided multiple sources, from racing damper and suspension manufacturers that clearly states that firmer dampers = harsher ride.
- Show your understanding about damper, the information from you usually only apply on certain behaviour and can not be applied on other behaviour (inconsistent damper physics).
I would like some examples of how my information is inconsistent. Almost every single thing I have posted is supported by reputable source material. You on the other hand have a history (that still persists) of presenting your own theory as fact, of misleading members over testing you have carried out (or not carried out as the case may be), not supplying source material and when you do cite sources you have often misquoted or miss-understood them. For example, the source you provided to ‘prove’ that stiffer dampers were not harsh did nothing of the sort; you completely failed to actually understand your own source material. I read every word of that document and at no point did it state that stiffer damper did not increase harshness. You took references to ride comfort and used them to try and support your own theory.
In addition its not just me that you are saying does not have an understanding of damper technology, but also almost every other member who has posted in this thread and the source material authors that I have used (as I have remained consistent with that source material).
- If you can't explain the difference between soft or stiff damper in many situation, I don't expect you to know how to judge GT4 damper.
Uh I can and have, not only that but I have real world experience of this and have also trained in the area of vehicle dynamics and suspension. Once again I ask what exactly qualifies you, the person who a year ago said they did not really care how GT physics worked, but preferred to reverse engineer it.
Sucahyo
Maybe, but, since I don't work in automotive area, even though its nice to know what the real life physics does, I prefer reverse engineer GT physics for my tuning.
In addition I think its worth remembering that you actually made your mind up about GT4 damper values being reversed before you actually had any real experience of GT4.
- If you can't tell what soft damper do or what stiffer damper do in many situation, I just can't trust your opinion about GT4 damper lower is softer.
When exactly have I failed to discuss or explain a real world situation or application of soft vs stiff dampers?
I have dismissed your ‘nonsense’ requests repeatedly as they have no relevance to either the real world or GT4, your persistence with them is also rather tiring as they serve purely as a distraction and are of no constructive use.
- I ask you to explain how different damper stiffness react or move in an isolated way to know, wether you really know about damper or you just think think that you know. "it sink" is not the kind of answer I expect from someone who know about how damper react or work.
Your explanation consistency is a big problem.
I bet it will be impossible to explain all of this consistently:
- stiffer damper has slower reaction
- very stiff damper bypass suspension and transfer force directly to car
- stiffer damper "slows down the motion"
On soft damper explanation the number two explanation give error.
No it does not, the issue here is with your understanding of this and I believe miss-reading (and I hope not deliberately) what I am saying. I have explained these areas a huge number of times and the
only person who has an issue with them is you.
I must say that I do in particular like this part...
Sucahyo
I ask you to explain how different damper stiffness react or move in an isolated way to know, wether you really know about damper or you just think think that you know
..., may I ask what exactly qualifies you to even judge if I am right or wrong on any automotive topic. Specifically what work have you do within the motor industry, training attended, etc. I ask because a little over a year ago you had no knowledge at all of damper physics and reactions, now unless you have attended some specific training in this area, I strongly suspect that you are the one lacking in formally tested knowledge.
To be blunt about it you have dismissed every other member here at GT Planet in regard to our understanding of dampers and categorically stated that our understanding of every single piece of source material is incorrect, and your qualifications for this are the info you have picked up off the 'net in the last year, most of which is written in rather technical terms in a language that is not native to you. Once again
Occam's Razor comes into play here, put simply it is far more likely that you are the one who is incorrect and has failed to interpret the source material, than for every single other member involved to have done so (oh and every engineer and automotive lecturer I have spoken on the subject with as well).
Put more specifically Sucahyo a large amount of your input into various discussions on tuning has either been poorly thought out, flawed or just plain wrong. You have failed to prove you point in regard to the issue of reversed damper values, in addition you have failed to 'prove' the merit of your own tuning theories and have sailed so close to AUP violations that is got beyond a joke.
Try to mention all of this when you explain how damper work, can you?
To repeat:
Scaff, can you explain how damper work when receiving single direction movement (bump) without spring equipped?
What happen when the tire receive bump, second by second until right before the suspension bottomed out, with the assumption that the k1 and k2 is null. How the speed change, what is the difference between stiff and soft damper, how much force recieved by the car, how much force is lost, how much different the damper will react on different bump speed, etc.
not neccesarily on car. What a stationary damper (one end attached to solid object) do when it receive force. Don't answer it just by "it sink", answer it more descriptive please. Answer how damper react, and also what is the difference between stiff and soft. Is it too hard for you to explain the sink difference between soft and stiff, which one reach bump stop faster, what happen to the force when soft or when stiff?
OK I don’t know what it will take to get this through to you, and my patience is wearing very, very thin.
What happen when the tire receive bump, second by second until right before the suspension bottomed out, with the assumption that the k1 and k2 is null
If k1 and k2 are null then the car will already be bottomed out, why can’t you actually understand this, dampers don not support weight at all, without the springs in the system nothing is supporting the sprung mass at all. The car will already be bottomed out (sat right on the bump stops).
As an example this has no relevance what so ever, it serves no purpose at all and has no real world application in any way and I have go as far with it as I am willing to.
When I reopened this thread I did so under a number of conditions, and just to remind you they were:
Scaff
However I open it again on a couple of provisos
1. Any test discussed must have been carried out by the member who posts it and full settings must be included
2. Opinion as fact will not be tolerated, sources must be provided
3. The AUP will be enforced to the letter
You have failed to meet a number of these provisos and quite frankly I’m on the verge of locking this thread once again. Your question has nothing at all to do with proving one way or another if GT4 dampers are soft or firm at higher values. Stop with the crap and do it right now.
Ok, stiffer damper make ride more uncomfortable (harsh), but I don't agree that stiffer damper make more suspension movement (vibration) and noise (sound harsh), your source don't even mention this while my real life experience said no.
I do love the way you accuse me of not being able to read things and then post the above. I did not say that stiff dampers will make the ride more uncomfortable, I said (and have backed up with numerous sources) that stiffer damper are harsher. Comfort will depend on far more than this and can be a personally matter, I don’t find my Celica uncomfortable at all, but my wife does, I would however never dispute that over broken road surfaces it’s a harsh ride.
In regard to inconsistency you are now saying that you “don't agree that stiffer damper make more suspension movement”, well that’s great because I’ve never said that they would. It’s rather a pointless thing to say in that context.
In regard to your real-life experience, well that we have already covered on a number of occasions, you did not work on the car yourself, you are trying to cover all areas of NVH under the remit of dampers and are not actually able to prove that a firmer damper was installed rather than a replacement for a faulty damper.
Most concerning of all you have failed to address why everyone else disagrees with you, and more importantly why you have not been able to come up with a test that repeatedly proves that GT4 dampers are reversed. I have come up with a huge number of differing tests to support my position and when run by other members they are all in agreement, higher values are stiffer. Now either we are
all wrong and the only person here who actually understands damper is you, or you are wrong. Given that the majority of consensus (following round after round of tests) is that higher values are stiffer and that a number of members who have commented and run these tests have experience with adjustable damper and actual track experience I find it far more likely that you are wrong.
So I tell you what, stop all the rubbish and put together a series of tests that clearly show (under a range of damping situations) that higher damper values in GT4 are indeed softer. However you have to ensure that these results will match with real-world damper reactions, these should be sourced and relate to automotive damping reactions.
Basically what I am saying is ‘Put up or Shut up’
Scaff
