Suspension Theory/Chat Thread

[LucasBlack]

Originally Posted by midnightex

WOW... I just read the whole thread and I feel like my IQ has dropped (not meant as an insult, I was speaking comparatively).

You guys really know your stuff.

So here's my question:

What would make the progress springs' linear rate be more beneficial than a progressive rate spring like the ones in an Eibach Pro-kit?

glad someone new has found some interest!
as always, i recommend the forum stickies because they themselves are a wealth of information as well. happy learning!

[Sirbelch]

Aki does have a point about the streetability of the progressive rate springs just as we have a point about linear rate springs being better for handling purposes.

[blueroadster]

Originally Posted by Sirbelch

It is going to be a compromise for all people. Those coilovers, as well as any other of the shelf coilovers, are ment to meet the needs of the many, not the needs of the few, or the one, the one. So, they might be good for one person, but suck for another. Having the ability to adjust pre load sparate from ride height really doesn't do any thing. The spring has a liner rate, so no matter how much pre load you put on the spring, it is still going to compress at the same rate. However, the more pre load you put on the spring, the less suspension travel you will have under compression (bump). Also, you have no idea what those 15 levels of adjustment do. Does it increase bump damping, rebound damping, both at once, at what rate does it do those adjustments and where in the shock dyno curve does it change the rates? It would be ok for some street and fun at the track, but, for me, not knowing what its doing does not make it a good choice.

Thanks for the detailed reply.

[Sirbelch]

Originally Posted by blueroadster

Thanks for the detailed reply.

No problem. I to do it every chance i get for everyone with in my scope of knowledge. If you want a ridiculous set up, contact Highrev1 of RedShift Motorsports and ask about the custom set ups. I have had Tein SS and Tein Flex and am now getting the Double Adjustable Custom Koni Coilovers from RSM. I can't wait. They are going to be the best suspension ever (well for me anyways).

[Sirbelch]

Question time.

How does lowering a car affect the roll center of the car? I.E. if you lower the front and rear the same or you lower the front or rear lower than the other.

[midnightex]

Don't all cars actually have two roll centers? One for each end of the car?

My guess would be that since each car has two roll centers, lowering each one independently of the other would be fine as long as the amount of drop is appropriate for the type of suspension (i.e.: double wishbone, live axel, etc.).

I think that the biggest concern in lowering the car would be to make sure that you don't upset the balance between the two. You wouldn't want the rear of the car fighting with the front of the car.

Just my overly simple guess. I'm hear to learn, but it's fun to take a stab in the dark.

[Highrev1]

"The geometric roll center of the vehicle can be found by following basic geometrical procedures when the vehicle is static. However, when the vehicle rolls the roll centers migrate. It is this movement of roll centers that vehicle dynamicists seek to control and in most cases limit. The rapid movement of roll centers when the system experiences small displacements can lead to stability problems with the vehicle. The roll center height has been shown to affect behaviour at the inititation of turns such as nimbleness and initial roll control."

Basically if you lower your car too much and the front control arms get angled up you are killing your roll centers...By doing this you are severly hurting transitional turns. Don't get me wrong lower can be good if it is done properly but too low and you have to correct the roll center back up otherwise the car won't handle well in transitions.

2 basic solutions..First Just don't go TOO low. This is not just becuase of the roll centers but for numerous reasons..I would Gregstimate it to about 1.5" But only real testing will give a hard proven number....The second solution is what alot of the RSX guys did and get longer ball joints...You can read more here http://forums.clubrsx.com/showthread.php?t=373563

[toxin]

Originally Posted by LucasBlack

think about top fuel drag cars and the like: through centrifugal forces, those huge slicks actually narrow their contact patch as they accelerate, thereby reducing the amount of friction existing between the car and the road, therefore reducing resistance.

with all that said, why would we completely rely on friction to be quick?

Jesus Christ. There is so much wrong with this I don't know where to begin.

1. Centrifugal force doesn't exist
2. Narrowing the contact patch of your tires doesn't make you faster (lol)
3. "Reducing resistance" between your tires and the road CERTAINLY doesn't make you faster (LOL!)

Next time before you try to sound smart, 1. make sure you are smart, 2. make sure your logic is logical.

The signal to noise ratio here is disgusting.

[Highrev1]

Easy there killer...... We like to have nice civil debates in here Lucas and TOxin I want you both to be nice now....Don't want this thread closed!!!

Where was that posted??

[toxin]

It was back on pg. 15; I shouldn't have bumped it up. I was just reading through this thread trying to find the hidden nuggets and that one made my head explode.

I guess he was just trying to foster discussion, so I apologize. I just hate hate hate when folks spread ignorant misinformation in w/ the good info that posters like you and belch are posting, because you know a lot of the n00bs don't know what noise to filter.

[Highrev1]

Hey I post up ALOT I mean ALOT of BULLSHIT!!! So once in a while even the initated are allowed to mess up

Toxin hope to see you around here more....Lucas

[LucasBlack]

Originally Posted by toxin

1. Centrifugal force doesn't exist

is my terminology incorrect? because as something rotates about a center, there is tendency for it be acted upon to move outwardly from that center, what problem do you have with that?

2. Narrowing the contact patch of your tires doesn't make you faster (lol)

if you are able to maintain maximum acceleration with three square inches of contact, what benefit does four square inches bring?

3. "Reducing resistance" between your tires and the road CERTAINLY doesn't make you faster (LOL!)

reducing traction is not faster, but reducing resistance is. it's a fine play between the two...

Next time before you try to sound smart, 1. make sure you are smart, 2. make sure your logic is logical.

try some tact next time, and some embellishment behind your statements.

The signal to noise ratio here is disgusting.

for someone who hasn't invested much signal to this forum, you sure are making a lot of noise....

[LucasBlack]

Originally Posted by Highrev1

....Lucas

hi ya Greg, how's the things that are your life?

[Highrev1]

GOSH darnit both of you this is a suspension theory chat thread NOT about drag racing I hate DRAG!!!!!!

TOXIN I see you replying be nice you are the NEWB!! THen we can move on guys...

[Highrev1]

So who wants to discuss the Wheel rates on our cars???

[toxin]

Originally Posted by LucasBlack

is my terminology incorrect? because as something rotates about a center, there is tendency for it be acted upon to move outwardly from that center, what problem do you have with that?

Its tendency isn't go "move outwardly from the center," but rather to continue traveling in the same direction (in a line tangent to the circle, basically). It's just Newton's first law. There is no special force at work.

if you are able to maintain maximum acceleration with three square inches of contact, what benefit does four square inches bring?

grip = (coefficient of friction) * (surface area)

reducing traction is not faster, but reducing resistance is. it's a fine play between the two...

I guess, but in the context of tires, the benefits of an increase in traction are always going to outweigh the negative effects of an increase in "resistance."

try some tact next time, and some embellishment behind your statements.



for someone who hasn't invested much signal to this forum, you sure are making a lot of noise....

Sorry for the lack of tact. It honestly seems that you are misrepresenting your expertise, though, which is bad for the noobs.

HighRev: look at my reg date homie. noobness = knowledge, not f'n post count, c'mon man, that's weaksauce.

[Highrev1]

Ok fine now DONE!!!!!

Wheel RATES who wants to BEGIN????

Yodum's Want to begine I see you there AKI I know you know your SHiat you could start the discussion!!! SOMEOne!!! :)

Well I am leaving work now so EVERYONE BEHAVE IN MY THREAD....Especiallly YOU YODUMS!!!!

[aki]

Originally Posted by toxin

Jesus Christ. There is so much wrong with this I don't know where to begin.

1. Centrifugal force doesn't exist
2. Narrowing the contact patch of your tires doesn't make you faster (lol)
3. "Reducing resistance" between your tires and the road CERTAINLY doesn't make you faster (LOL!)

Next time before you try to sound smart, 1. make sure you are smart, 2. make sure your logic is logical.

The signal to noise ratio here is disgusting.

1) Yes centrifugal force does exist. If it's spinning, there's centrifugal force.
2) Well at least for the front tires it does. Dragsters use skinny tires up front.
3) This is true. You want to maximize friction. Hence lower PSIs used to have more contact patch.

[LucasBlack]

Originally Posted by aki

3) This is true. You want to maximize friction. Hence lower PSIs used to have more contact patch.

and aerodynamics can assist in traction without necessarily relying on contact/surface area.


but indeed...enough about traveling in a straight line - boring!!

[Highrev1]

Lets dicuss our wheel rates....


"Figure 1 shows the relevant parameters involved in calculating the wheel rate based on knowledge of the spring rate. Wheel rates are useful to know as they make it possible to compare rates between chassis' with differing suspension layouts. Wheel rate is also nice in that it gives one a better feel for the front to rear rates on a single car when the two axles have differing motion ratios (L1/L2, see below). It might be helpful to think of wheel rate as the effective spring rate when the spring is actually installed onto the car. "

Wheel Rate = F2/dw = k1(L1/L2)²

Wheel Rate = Spring Rate x (Motion Ratio)²