Are damper settings supposed to be stiffer at the front??

[KaiZen]

I've been searching the posts and I can't seem to find a definitive answer to this question. I understand that sping rate's should be greater (or am I wrong?) because of the amount of weight transfering to the front of the vehicle will always be greater under braking due to momentum compared to weight travelling to the rear under accelleration, but does the same rule of thumb apply for dampers?

Something that has been racking my brain for a while now is whether or not front bound and rebound settings are supposed to be stiffer than they are at the rear. I've read alot of detailed information about how the bound and rebound settings effect the weight transfer but still have not come with a conclusion.


How about an example? An FR car like a silvia or other with a weight distribution value of about 55:45.. and a s2000 or rotary with a 50:50 distribution.. and an NSX with 40:60 value..

It doesn't have to be these cars in particular, but you get the idea..



Thanks peoples and keep up the good work.. maybe a huge tuning guide should be compiled so I don't waste so much ink printing out banners. Lucky I do it at work!

 

[bostwick_965]

KaiZen
I have read a couple of real life handling guide for street and race cars. Most if not all of the information in them can be applied to GT3. The guide states that the stiffer your susespention is at one end of the car the less traction it will have. It also states that with stiffer rate response is increased due to more weight transfer. So when you hit a corner and brake weight is transferred to the front of the car which at this point will be steering. Your front springs and dampers and stabilizers are used to carry the weight. When you accelerate out of a corner weight will be transferred the back of the car. Stiffer would seem to be better the reason it is not is because, lets say you had a car frame with no suspension so full stiffness when you hit a corner weight is transferred instantaneously to the outside increasing its contact patch but is also lifting the inside tire contact patch almost to the point where both inside tires lift off the ground. This is bad because you want equal weight distribution at all states in handling. This also creates a problem because you have overloaded the outside tires while reducing the inside tires traction. So more weight transfer happens at the stiffer end of the car there by reducing traction. This means that which ever end needs more handling should get lighter spring damper and stabilizer rates. In contrast though weight will always be transferred and a little more weight at on end can help traction at that end but not to the point of tire overload.

Now to answer your question I have found that that softer damper at the end of the car that need grip is better. I will explain dampers a little damper bound is how fast a spring compresses or shortens lower rates mean slower compression higher rates mean faster compression. Again stiffer means more weight transfer. Damper rebound is how fast the spring uncompressed or returns to normal. Lower rates mean slower higher rates mean faster. Again stiffer means more weight transfer. Okay now when you accelerate the front rebound is used and the rear bound is used. In braking the front bound is used and rear rebound is used. In my opinion Bound is more weight receiving determiner and rebound is more responsible for weight transfer speed determiner. So let’s say you have a FR car you want more traction in the rear because your car is slipping in the rear due to a loss of traction. You could stiffen the front rebound making the weight shift to the rear a little quicker then lower the rear bound to increase traction at the rear which will now be able to handle the greater load this prevents some oversteer and traction loss or could also be said to increase understeer. Like stated above a little more weight at one end can help handling. The opposite lowering rebound and increasing bound will make a car loss more traction in the rear inducing oversteer or lowering understeer. In braking you could lower rear rebound making weight transfer slower to the front of the car while raising the front bound this will make your car oversteer at the beginning of a corner. The opposite high rear rebound and low front bound has the tendancy of making your car understeer at the beginning of a corner.

Now as I have found through Neon Duke that GT3 does bottom out cars if there ride height is either not high enough or does not allow for full suspension travel. This is why you can’t lower your car completely and make the suspension totally soft. This also makes your car respond to your steering feedback ultra slow. Stiffening suspension can help this problem. So in all you have to balance all of these factors to find the best rate for you.

I hope this answers your question.

 

[chishifu]

stiffer rate response is increased due to more weight transfer

Ok, before sukerkin decides to get in on this conversation and blow us all away =P i'd like to say a few things. First of all.... a stiffer rate does not induce more weight transfer, it simply allows the weight to transfer more quickly. A car will not magically gain more weight just because one end of the car is stiffened. However, bostwick was correct in saying that if weight is instantaneously transferred to one side of the car, the tires will be overloaded, and all the horrible horrible things that come with it =P

Well... Kai Zen, i would suggest you read as much as you can about this stuff, in this forum and outside, if you haven't already done so. Even though it doesn't tell you what end to make stiffer, if should answer your question. But i'll just answer it right now with the limited knowledge i have about car physics and tuning.

Ok, again, bostwick, bound, or bump, does control the rate of compression of the suspension. However, in general, bound majorly affects car balance when hitting anomalies in the road, ie: bumps. Rebound is the major factor in tuning a car's balance during internal weight transfer. Therefore, whether or not you like them stiffer in the front of the car is a matter of taste, but i'll attempt to explain what it does.

Ok, stiffer front bound settings. When you hit a bump, more traction is lost than if the settings were lower. Consequently, some understeer should occur. If thinking in terms of weight transfer, stiffer front, transfer weight forward quicker, overload tires, the car pushes. This is very very narrow--minded, but imo, that might be what happens. However, everything you do when you tune is a compromise, and it depends on corner entry or exit. In addition, rear settings do have an enormous impact on overall car balance.

Stiffer front rebound settings. This will speed up weight transfer to the rear of the car under acceleration. As i said above, this will promote grip in the rear tires until they are overloaded, at which time rear tires lose traction and oversteer is promoted.

So, a combination of stiff front bump and rebound settings seem to compromise overall. Now that i've explained what happens, here is why stiff front settings are generally preferred. As you stated with your examples, weight distribution along the car differs with respect to drivetrain and engine placement. Bostwick also stated that a cars weight should be equally distributed throughout to promote equal traction and thus predicatbility. However, with front-engine cars, more weight in the front means more force on the front suspension. With a soft front suspension, this extra force may cause the car to bottom out, producing instantaneous weight transfer. That is most definitely unwanted, and stiffer settings help prevent that.

Well... those are my ramblings. feel free to pm me to argue or whatnot, HOpefully not ALL my information has been wrong. Waiting for your reply sukerkin.

ChiShi

 

[bostwick_965]

Sorry I did not mean that more weight would be anded because of stiffer shocks just that weight would be tranfered at a more faster rate than it usually does My apologies.

Thanks chishifu for the additional info on dampers and clarifing things a bit more.

 

[KaiZen]

OK.. so was I wrong in assuming that the front springs should at least be stiffer than the rear? I don't care about personal preference, I want to at least apply real world settings and from what I've seen on certain DVD's with tuned cars on them they all have stiffer, by a couple kg's, front than rear. They show spring rates in kg's but always neglect to mention damper settings! In terms of pressure, do dampers also have the same sort of value system per sq. inch or cm or mm, or whatever?.. Personally, I think most people would just make the front end softer in every way in order to have more grip. But, I would like a more mechanical real world approach, like if I was a race engineer!

Is it safe to assume, then, that dampers are not set in the same way? That the springs are already dictating where and how the weight is being transfered, but it's the job of the dampers is to control this transfer, therefore thinking that the damper settings need to be stiffer due to a greater weight transfer is mechanically incorrect? Personal preferences aside, of course.

<smoko>

damn I lost my train of thought. I think of more questions..

Thanks for the replies guys.. Someone please put a highly detailed guide to tuning, even if they aren't all based on fact and are just someone's humble opinion!

Cheers

KZ

 

[KaiZen]

Just remembered what else I was going to say, it nevered occured to me before but reading some of the other threads have confused me on the way the values for the dampers works. I always thought that raising the value would stiffen its function; stiffening the bound would make it 'slower' or harder to compress and stiffening the rebound would allow it to decompress faster. As I think of it now I still believe that raising the value for the bound would make it stiffer therefore compress slower but raising the value of the rebound may also make it stiffer and therefore DE-compress slower too..

I know it's probably been argued back and forth over this forum so I'd just like to add that I'm officially confused and this is a pretty F@!<ed up issue.. dang!


Now back to the issue at hand though, again it has probably already been brought up but since we're on the issue and, admit it, it will never get old and will always be interesting, what do the springs do?.. Do they just work on a whole? I mean, do they do everything like control the weight transfer, absorb bumps, etc..? How stiff should the springs be? Springs and dampers should work together but adjusting dampers seems easy compared to adjusting spring settings since dampers have a value between 1 and 10 compared to springs which can be adjusted per 100g!

Do the springs effect the car so much compared to dampers?

If it is already posted elsewhere just point me in the right direction.. I'm really starting to get a good grasp on damper settings, thanks to all you guys, and now I got the spring on my mind..


Thanks again.. Cheers!

 

[chishifu]

Haha, Kai, we have so much in common. These were the exact questions i asked not too long ago. About the number value of the shocks/springs and so forth, it's ambiguous, there is no solid fact that i've seen so far. Many renowned gt3 tuners say contradictory things, but in general, it is agreed upon that a higher value indicates stiffer shocks/springs.

something i tried myself was just putting a full suspension on a stock car, raising ride height to the max, and doing the extremes with the shocks. Just from observation, see which one is which. I'll add more when i have time

ChiShi

 

[KaiZen]

Thanks for your help dude.. I higher value for the bound and springs I understand, but for the rebound, I'm not so sure now.. will increasing the rebound value stiffen the rebound therefore slow its rate of decompression?

I'll experiment with it when I get home from work but that will be hours away..

 

[sukerkin]

Ok, before sukerkin decides to get in on this conversation and blow us all away =P i'd like to say a few things.

<snip>

Well... those are my ramblings. feel free to pm me to argue or whatnot, HOpefully not ALL my information has been wrong. Waiting for your reply sukerkin.

ChiShi

How did you guess that this was a thread that would attract my attention Chi ?

I don't have time to read through in detail right now (at work ... as usual ) but I'll have a look later today if I get the chance.

On the whole tho', I would think that a quick look at the previous thread where this was discussed should provide a bit of insight for you, Kai.

 

[sukerkin]

This is the thread I was talking about:

https://www.gtplanet.net/forum/showthread.php?t=50112&page=1&pp=20

 

[chishifu]

Hey sukerkin, quick question, after reviewing some of those old resources, it seems like you're saying a stiffer front bound will slow the rate of compression during braking?

Imo, shouldn't it be the other way around? The stiffer end should cause weight to transfer quicker ie: a car with no suspension and you hit the brakes. The front bound is infintely stiff, and well, logically, in this case, no dip occurs in the front end but weight is transferred instantaneously. Just my ramblings

ChiShi

 

[sukerkin]

Hi Chi

If you think about what a stiffer damper is actually doing then it becomes a little clearer.

A 'stiff' damper is not allowing the spring to compress as quickly as it wants to in a given circumstance i.e. it is preventing that end of the car dipping so rapidly but the 'weight shift' still passes through the tyre to the road and does so more directly.

Now that energy is still there ("You cannae change the laws of physics Captain!" ) but what the damper does is dump some of that energy as heat (which it absorbs in its high density oil in most cases).

Remember, in the end, the spring will still compress by the same amount but the damper is taking control of how quickly the spring reaches that state of compression and a stiffer damper 'spreads' that energy out over a longer period. However, because the damper is part of a system that includes the spring and the tyre (and the road too I suppose) then the stiffer damper translates the weight shift more rapidly than a softer one but slows the Centre of gravity change.

Perhaps a good way of visualising it is to imagine the difference between dropping a ball bearing into water and dropping it into thick oil. In the water it goes straight to the bottom immediately but in the oil it sinks more slowly i.e. the weight moves less quickly (the stiffer medium tho' means that whatever the container is resting on receives the energy more directly).

In short, Chi, you're right ... why I have to waffle on I don't know ... must like to hear the sound of my own typing . But you have to bear in mind that altho' the term "Weight Transfer" is bandied about quite liberally it doesn't mean the same thing in all circumstances and sometimes people (including me ) are talking about CoG changes instead.

I don't know if that helped or not. As ever, please don't hesitate to say if I've made matters less clear or if you vehemently disagree.

 

[sukerkin]

A quick precis of 'realworld' advice on some aspects of damper tuning (bearing in mind that GT doesn't do lateral weight transfer through the dampers (or at least we can't tune for it)):

HANDLING TIPS FOR DAMPERS

Short Tracks: Softer all the way around.
Flat or Tight Turn Tracks: Softer rears.
High Bank Tracks: One step stiffer on RF & RR.
Want Understeer Going In: Softer compression on RF or stiffer rebound on LR.
Want Oversteer Coming Out: Softer RR or stiffer rebound on LF.
Want Oversteer Going In: Softer rebound on LR or stiffer RF.

 

[sukerkin]

One final thought - a big rule of thumb that I use when tuning cars is that I make sure I know what the cars weight is and how long and wide it is compared to the wheel base and front and rear track.

I then divide by 100 and set my dampers Bound rates so that they add up to that figure e.g. if the car weighs 1100kg then I try my dampers Bound at a total of 11 (usually 6 Front and 5 Rear for a 'normally' proportioned FR car) with Rebound about double that.

This has no obvious 'scientific' basis, it's just a RoT I've found very useful over the years (more useful in fact than the professional suspension tuning software I have that costs a couple of grand because it needs parameters we just don't know in GT3 !).

 

[KaiZen]

Thanks for the input Sukerkin but you've confused me abit.. RF,RR,LR,LF? what do these mean?..

Question: stiffening the bound will slow down the compression, but stiffening the rebound will slow down the decompression or increase the speed of decompression? and I'm not talking about the whole confusion as to whether the values are stiffening or softening the dampers..


I'd like to see how you guys would set up an S2000 type V(J) on Deep Forest..

Mine so far.. still tweaking:

Fully Tuned Race Setup: 544HP on Super softs (T8)

Springes: 13.8/12.2
Ride: 90/90
Bound: 4/5
Rebound: 8/6
Camber: 3.5/1.5
Toe: 0/0.5
Stab: 4/5
Brake: 18/13
LSD: 2 way
Auto gear: 27 (my friend has this thing about having a 260km/h top speed so I'm amusing him, for now..)

Without playing with the gears and LSD I've set a best lap of 1:09.310 with a few minor mistakes. With the right gearing and LSD setup I'm sure I could get into the low 8's and possible 7's if it were't for the gearing as you hit the limiter a few times on the straight. I used to play around with the LSD a few years back, I still remember how much of an effect adjusting it has on the car, and I'm sure I still remember how to adjust it so just try out the gearing and 2-way diff and let me know what you think about this setup, please, of course.

But, like I said, I'm just 'amusing' my friend. He's been playing for years and he's never touched the setup screen. He used to add full custom everything and just adjust auto gearing a click or 2 and disable TCS and ASM. It took me over a year to convince him that i'll teach him how to setup his car because he was so F@!<ING LAZY he'd just neglect the idea and it really used to piss me off because he used to call himself a racer and.. sorry, I'm rambling. Just hate people who think they've mastered the game just because they've spent countless sleepless nights playing when they haven't even begun to enjoy the Gran Turismo experience. So.. I'm slowly teaching him about suspension settings and teaching him how to setup his LSD, I fear, will just confuse him too much! And GT is fun again.. I took a break for a while because I had noone to play with =(

Though I've been customising my setup's from the beginning and always felt I was fast and consistant, you never stop learning.. or getting faster either!


So thanks again for your input Sukerkin, and Chishifu.. I'll be on the comp for another 8 hours (at work) waiting for your reply..

Theres still the question on the springs. What's the best way to set them? The thread you linked had great detail about the dampers and shed some new light, on my side, about setting them up, but, now I'm concerned about my spring rate settings.

Cheers guys!.. Try my setup and demolish my lap time.. I'm sure you can!

more to come, I'm sure....

 

[KaiZen]

Your final thought, Sukerkin, sounds interesting.. I'll try it after work.. Especially interested in the suspension software. What do you do dude? Some kind of suspension tuning house specialist or something? And where can I get that software? =)

 

[sukerkin]

Thanks for the input Sukerkin but you've confused me abit.. RF,RR,LR,LF? what do these mean?..

Sorry for the confusion - those abbreviations simply stand for Left Front, Right Rear etc.

Question: stiffening the bound will slow down the compression, but stiffening the rebound will slow down the decompression or increase the speed of decompression? and I'm not talking about the whole confusion as to whether the values are stiffening or softening the dampers..

Leaving aside, as you say, the 'game' issue of what the values on the screen mean, a stiff rebound setting means that the spring is not allowed to uncompress so rapidly.

I'd like to see how you guys would set up an S2000 type V(J) on Deep Forest..

An interesting idea. I'd far rather be running it with fewer horses and harder tyres tho'.

Theres still the question on the springs. What's the best way to set them? The thread you linked had great detail about the dampers and shed some new light, on my side, about setting them up, but, now I'm concerned about my spring rate settings.

GT3 is relatively insensitive to changes in spring rates I've found. For me the Dampers are nearly always the key. The stock spring rates for the race bodied cars never really need altering, they're fine as they are. The rates for a 'tuned' street car tho' are always way too soft. I'd say that mostly I have the front rate higher than the rear (sometimes as much as 4kg) and tend to set that rate at around 1.5 times the (weight of the car/10) e.g. a 1000kg car I'd start the front spring rate at 15kg and work from there.

 

[sukerkin]

Especially interested in the suspension software.

Unfortunately the license costs many pennies and in order to use it you need to know in detail how the suspension of your car is put together (dimensions and spacing of swinging arms, pivot points, CoG etc etc) so it's of no utility for GT3 .

What do you do dude? Some kind of suspension tuning house specialist or something?

Ah, if only I did this for a living ... instead I design software control systems for the power industry.

I just got caught up in the intricacies of tuning and basically spent a couple of years teaching myself 'how stuff worked' so that I could set up cars better. As a result, a racing driver friend of mine did make the offer to let me 'spanner' for an independant team but I, foolishly, never pursued it (that'd be far too much pressure !).

 

[sukerkin]

Had a furious coupleof hours spannering a maxed out S2000 @ TM and here's what I came up with:

Springs: 12.8/11.8
Ride: 100/96
Damper B: 5/6
Damper R: 8/9
Camber: 1.3/1.2
Toe: -0.5/+0.0
Stabs: 4/4
Brakes: 20/15
LSD I: 10
LSD A: 40
LSD D:40

Gears: Tranny Trick and then Final to 3.310

ASM: 0
TCS: 0

She'll do mid 1:21's to high 1:20's shod with T8's.

Because I didn't want to be influenced by your settings work-up I didn't look very carefully at the post you made and thus, as noted above, have been using the 'wrong' track (Trial Mountain rather than Deep Forest . I'll go back and have a play at DF - report in tomorrow.

 

[KaiZen]

Thanks Sukerkin!.. Youve been unbelievably helpfull.. I havent tried my car on Trial Mountain yet but I will soon.. If your gonna shoot for my time in Deep Forest remember that I only had the gears set at 27 without any tuning.. and a 2-way diff. I made a slight typo above on the damper settings and last night made a slight change that made a heap of difference, thanks to you of course. So far I've just been tuning the car on DF, coz it's our fave, but the car seems to work well on Grand Valley too..

Settings Updated:

Deep Forest: 1:09.290 (still not perfect. 9 flat is definately possible!)

Springs: 13.8/12.2
Ride: 90/90
Bound: 5/3
Rebound: 9/5
Camber: 3.5/1.5
Toe: 0/0.5
Stab: 4/6
Brake: 18/13
LSD: 2 way
Auto gear: 27 <------ don't forget this if you want to shoot for my time. Top Speed 264km/h



Thanks again guys!.. I have a new found approach to my shock tuning which has made a huge difference to getting my cars to handle the way I want them to, and I will experiment a little with the spring rate tips. Damn You Guys Rock!!..

Cheers!.. If only we lived in the same country I'd shout you's some drinks, but this will have to do!..

KZ

 

[KaiZen]

I'm also interested on how you's would go about setting up a 4wd and MR car..

step by step how would you start setting up your car.. if it's FR, MR, 4WD.. actually start another thread..

 

[KaiZen]

BTW Sukerkin.. your LSD tuning looks like it's the same as how a 2-way LSD would work, but with a lower initial..

 

[sukerkin]

Very true Kai.

It's purpose is to keep the back end from getting too unruly over all those bumps and drop-offs around TM. I usually prefer the LSD Decel to be lower but in the case of the S2000 the back end unloads far too freely and the LSD provides a good way to control that tendency.

 

[KaiZen]

I understand completely what you mean.. it's the old 50:50 weight distribution trait where it seems to be fun hangin' your ass out one minute, then it'll spin out on you wicked fast the next.. Though from what I can remember, 50:50 cars, like the rx7, arent as edgy and out of control, therefore more fun , as they were in GT2.. correct me if I'm wrong.

Since I haven't gone around to tuning my LSD lately (I will in the coming weeks but I'm still unsure of when is the right time to start tuning the LSD while I'm tuning the Suspension/Chassis), I thought of tuning the Stabilizers or Toe to counter that..

Hey, like my new thread??.. please, take your time answering that one

The fun of Gran Turismo never ends!!

 

[chishifu]

Remember, in the end, the spring will still compress by the same amount but the damper is taking control of how quickly the spring reaches that state of compression and a stiffer damper 'spreads' that energy out over a longer period. However, because the damper is part of a system that includes the spring and the tyre (and the road too I suppose) then the stiffer damper translates the weight shift more rapidly than a softer one but slows the Centre of gravity change.

Perhaps a good way of visualising it is to imagine the difference between dropping a ball bearing into water and dropping it into thick oil. In the water it goes straight to the bottom immediately but in the oil it sinks more slowly i.e. the weight moves less quickly (the stiffer medium tho' means that whatever the container is resting on receives the energy more directly).

In short, Chi, you're right ... why I have to waffle on I don't know ... must like to hear the sound of my own typing . But you have to bear in mind that altho' the term "Weight Transfer" is bandied about quite liberally it doesn't mean the same thing in all circumstances and sometimes people (including me ) are talking about CoG changes instead.

Hiya again sukerkin,
Well, first off, you've managed to seriously confuse me, or perhaps make me question some of my former ideas. What you said makes perfect sense, that the spring will compress regardless and the damper only controls that rate. Consequently, stiffening the damper merely slows down the rate at which the spring compresses and allows the same amount of weight to be transferred but over a longer period of time. However, imo, with a longer distribution of the weight being transferred, this would promote grip and slow weight transfer right?

For example, stiff front bound or stiff rear rebound. (yes yes i know a car's weight transfer is mainly affected by rebound but bear with me real quick ) When prepping for a corner, we hit the brakes hard to slow to the appropriate speed. When we hit the brakes, this outside force counters the inertia of our car wanting to continue forward, and so the weight of the car is thrown forward. With stiff bound, this weight will be thrown over a longer time. Therefore, more time keeps more grip in the rear wheels because of the rebound, and the front tires are not overloaded as easily because of the stiff front bound?

I dunno, that is the example i could think of using my initial thoughts from your post. However, from what you said at the end about me being right and weight tranferring quicker with stiffer settings really confused me. Is it the other way around then? I just did all this stuff in physics.. i should know this -_-

Ok, long winded explanation of the ball dropping into oil. Say it falls from a height H. Before the ball falls, it has entirely potential energy. Then let it fall, and the instant before it hits the oil, it has both kinetic and potential energy. However, this energy added can only be equal to the amount of energy we started with. Therefore, the initial impact has the greatest force possible on the oil by the ball because the kinetic energy was the greatest. Afterwards, the outside force of the oil on the ball decreases the overall energy of the system and lowers the force of the ball on the oil, thusly slowing it's travel through the oil. When thinking of this with stiff dampers, most of the weight would be thrown forward at the initial braking, but weight is still slowly transferred throughout the entire compression sequence, so finding the correct damper settings involves finding exactly how much weight we can afford to throw forward initially. Is that right? sorry it's so long.

ChiShi

Oh, by the way sukerkin, you have the concept of CoG wrong. My physics teachers spent a month drilling this concept into our heads =P but yet, if the mass distribution of an object does not change, it's CoG will never change. If you think about it logically, it makes sense because the center of gravity is essentially the midpoint of all possible axi's? running through the car. If the mass doesn't move around, this point will never change. Just my ramblings of physics.

 

[chishifu]

actually, there's one more separate thing on my mind. You said sukerkin that a spring will compress all the way regardless of damper strength if given enough time. Imo, how much room the spring has to compress is determined by ride height. If that is the case, what effect does spring rates have? what exactly is it? I've never quite figured taht out. An example with an explanation would be greatly appreciate for both this spring and my damper questions. Thanks a lot man

ChiShi

 

[sukerkin]

Hi Chi

Let's see if I can't clarify all this a little bit as it seems that as time goes on it's getting a little muddier.

The springs, the damper, the stabalisers, the ride height, the tyre and the road all form parts of the system. GT3 doesn't model the tyre-spring effect and contact-patch deformation (that we know of) and we can't do anything about the road modelling either. So that leaves us the springs and the dampers as we aren't talking about the influence of the ride height and the stabalisers.

The springs primary job is to support the car and soften out the bumps in the road and they are rated to do that without being so soft that the chassis rolls too badly in pitch and yaw.

One of the dampers jobs is to quell the osillations in the springs so that the body of the cars isn't bobbing around all over the place but in a performance car they are also used to control the rate at which the springs compress and uncompress and thus become very useful in tuning cornering behaviour. They do this in three main ways:

1) Dumping the energy of the spring as heat by resisting the springs movement
2) Moderating the speed at which the spring length changes and so influencing the change in the Centre of Gravity of the car (talk about that in a minute).
3) Resisting the movement of the spring such that the transfer of weight to the road surface is more immediate i.e. a stiff damper in a sense 'bypasses' the spring and allows the weight to press down on the tyre straight away.

So a stiff Front Bound during braking, for example, stops the nose of the car dipping so quickly and violently, slowing the rate at which the 'effective' Centre of Gravity moves and also causes the weight transferred forward by deceleration to get to the tyres more quickly (which improves grip up to a certain 'overload' point).

As to the interpretation of Centre of Gravity, I think we could be running into a different use of the same term by Physacists and Suspension Engineers.

Essentially, when you are braking in a car, the momentum means that, as far as the tyres are concerned, the fronts have more weight on them than the actual weight of the car whilst the rears have less than they were supporting before. Also, the front springs compress and the rear springs lengthen so the car 'wedges' (front end down, rear end up). In other words, the CoG has shifted or at least is in a state of transit (which is why some of the equations for this can get quite complicated as the car is, in some ways, not considered to be a solid !).

As you say in a static physics frame-of-reference, the object is actually unchanged but, from the tyres point-of-view, the weight distribution has altered.

I hope that helps Chi as I'm somewhat at a loss about how to explain it any other way.

As always, bear in mind the caveat that this is just my opinion garnered from what I have read on the subject and it may be absolute twaddle .

 

[sukerkin]

Now, Ride Height and how it interacts with Spring Rates ... mmm ... can of worms here as we don't actually know what kind of springs are modelled in the game.

I've always assumed that they're constant (as opposed to 'rising') rate but the problem is that we don't know what the Ride Height represents.

Is it the stroke length of the springs (in which case that's wonderful as it makes things much easier) or is it the height of the sills from the deck (in which case we're into guessing as that data on it's own means nothing for suspension analysis). I've never reached a firm conclusion on this one - every time I start to lean towards it being the stroke length, I look at the F1 cars (which in RL have tiny stroke lengths) and realise it can't be .

As an aside, by the way, one use of the Ride Height is to shift the CoG fore or aft. In the game this has some unrealistic consequences (and an argument about that over at another forum got so heated that the forum imploded !). I don't like to tweak the ride height wedge much myself and will only do it if I need an extra fillip that I can't squeeze out of anywhere else in the suspension system.

In a nutshell, if you shorten the Ride Height you need to increase the Spring Rate (which is the resistance to compression that the spring has) to maintain the same resistance to bottoming out. This means that the car gets more responsive to inputs from the driver, which is good thing, but it also becomes more sensitive to inputs from the road, which is, in some cases, a bad thing.

In terms of GT3, as I've said elsewhere, the Spring Rate is a relatively insensitive adjustment (despite the tiny increments you can change it by) and it's really more about the balance between front and rear than anything else.

In the game you can run harder springs than you would on a real track of course as you don't have to worry about bits of the car snapping (or indeed your teeth shaking out ). But I'd still say that the best thing is to run springs as soft as you can (without bottoming out or having a car that wobbles like a jelly) and adjust for cornering with the dampers - that's the current theory that's in favour out there in Touring Car Land anyhow.

 

[chishifu]

Hey sukerkin, thanks for clearing some of that up. Makes much more sense now. So a stiffer bound/rebound setting in effect slows the time it takes for the springs to compress/decompress controlling the pivot of the car, but at the same time increases the rate at which tires receive or lose load right? This seems logical imo, to a degree. Like your example of a ball falling in oil. The initial impact receives most of the force and is the most violent, but then the ball falls controlledly(?) throught the liquid.

However, if the weight is transferred quicker, what happens during a longer corner? Weight is transferred quickly but the springs still have room to compress, what then? That has confused me. OH, another thing, what did you actually mean by the weight is tranferred forward more quickly under braking while the "effective" CoG is slowed? Is it because the wedging action is slowed but the tires are still receiving load? If that's so, what does the wedging action have on anything? Haha, i know i'm a curious duck, it you have time, all your input is much appreciated

ChiShi

 

[KaiZen]

Hey Sukerkin,

I'm still interested about what time you can get on Deep Forest with the autoset gears set to 27.. You too Chishifu..

I've been able to do a best of 1:09.031, but I know I can crack into the high 8's with some smoother driving and more tweaking..

My friend got a 1st intermediate of 22.548, 2nd intermediate of 49.018 and a final time of 1:08.919 - BASTARD!! 🤬


I know I'm faster than him, he's just has more consistant lap times.
I knew I shouldn't have given him tips on where to go faster! A month ago he'd be lucky to get into the 9's and now he gets into the 8's before me!!!! 🤬

Oh well.. finally I'm being challenged, I guess..


Mid 1:08's soon.. he'll never beat that!