well i installed my omnipowers the other day and my car sits perfectly how i want. But when i drive it i can feel my rear end bounce around off the slightest imperfection in the road. When i installed the coilovers i had to preload the fronts alot since the bottom colar was screwed tight to the strut and the rear isnt preloaded since it was alot longer and all i had to do was screw in the bottom collar to the right height. Is my problem do to me not preloading the rear coil or am i not used to having stiffer suspension. My last car had tein basics and it didnt feel like how my car is now thats for sure.

 

Preload

 

aight thank you

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by systemoverload &raquo;</TD></TR><TR><TD CLASS="quote">Preload </TD></TR></TABLE>

bullshit

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slammed_93_hatch &raquo;</TD></TR><TR><TD CLASS="quote">

bullshit</TD></TR></TABLE>

I second that, I preloaded the whole crap around 10x and more, and it still bounces all over the place.. Omnipower has issues with small imperfections..

On the track its fine, but road imperfections

 

Did u notice any difference though..Cuz im debating whether to leave it or go out and try to preload it. or would it just be a waste of my time

 

Difference, nope.. because preloading is never more then the weight of the car.. so as long as you stay within the limits of the short stroke damper, preload is just useless..

 

my rear bounces around too on certain road conditions, its just the nature of the coilover. monotube, fat piston, stiffer spring rate, etc.

 

As long as im ot the only person it makes me feel a lilttle better ...But yea i understand now...all i need now is to get strut bars and etc to stiffen up my chasis

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LaOstha &raquo;</TD></TR><TR><TD CLASS="quote">But yea i understand now...all i need now is to get strut bars and etc to stiffen up my chasis</TD></TR></TABLE>

no you don't understand and the strut bar wont do anything.

 

I keep hearing PRELOAD. What exactly does that mean? DO you perform it before you install it? Or after?

 

^^i would like to second that thought as i have much to learn myself...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EKhybrid &raquo;</TD></TR><TR><TD CLASS="quote">I keep hearing PRELOAD. What exactly does that mean? DO you perform it before you install it? Or after?</TD></TR></TABLE>

preload means that the spring can never rattle around. so when you jack up the car the spring is still in contact with the top mount and with the bottom collar.

you could do it be for you put them on or when you put them on, it really doesn't matter. because once the car has all four wheels on the ground your preload is completely negated.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slammed_93_hatch &raquo;</TD></TR><TR><TD CLASS="quote">preload means that the spring can never rattle around. so when you jack up the car the spring is still in contact with the top mount and with the bottom collar.

you could do it be for you put them on or when you put them on, it really doesn't matter. because once the car has all four wheels on the ground your preload is completely negated.</TD></TR></TABLE>

The only situation where preload might matter is with progressive rate springs. But since progressive rate springs are for pussies, it's a moot point, cuz none of us are pussies, right!?!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bad-monkey &raquo;</TD></TR><TR><TD CLASS="quote">

The only situation where preload might matter is with progressive rate springs. But since progressive rate springs are for pussies, it's a moot point, cuz none of us are pussies, right!?!

</TD></TR></TABLE>

right...

 

Something i learned today. If you put one inch of pre load on to a 400 LBS. You now have 400LBS of pre load and it will take 400 lbs of weight before that spring/shock moves at all. Now considering your spring rates the amount of preload you have and your wheel rate you could approach a pre load equal to that of the effective cornor weight on the spring and get a zero droop suspension. I dont remember the wheel rates for any cars off the top of my head but i will throw out 1.5 for an example. Consider you have a 500 lbs cornor weight on your scales. And you have 500 Lbs springs, at 1.5" of pre load you have eliminated droop. I think thats right but i am not going to draw it out and check. What does this all mean? For a normal car nothing but on some real fancey formula race cars they can run very low droop suspensions. Preloading your suspension will cause your car to ride slightly higher than it would with out the preload because some of the cars weight has to overcome the preload before it compresses the spring, but with the design of most coilover suspensions you have to move the spring perch anyway so it wont matter. The only place i can see preload doing anything for you on any kind normal street/race setup would be to stop your springs from falling out of the perches if you lift a wheel in a turn, so as long as your preload is greater than the weight of your rims/suspension your springs would stay seated. But i am no enginneer this is just a bunch of **** i been reading lately. hope fully if i said anything real messed some one will come correct me.

 

A suspension with no droop = bad idea.
And wheel rate is just the effective spring rate at the wheels, and you don't apply it when considering how far the springs compress under the sprung weight of the car.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Noob4life &raquo;</TD></TR><TR><TD CLASS="quote">A suspension with no droop = bad idea.
And wheel rate is just the effective spring rate at the wheels, and you don't apply it when considering how far the springs compress under the sprung weight of the car.</TD></TR></TABLE>

hahaha i read his post, and thought to my self, WTF why is having no droop good?


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ohjolt2 &raquo;</TD></TR><TR><TD CLASS="quote"> For a normal car nothing but on some real fancey formula race cars they can run very low droop suspensions. .</TD></TR></TABLE>

its a really bad idea to start comparing formula car to touring cars, they are in a whole different ball park.

 

Yeah that is as far as I understand... there was that post in the Autocross forum where Johnny Mac and that fellow Scott were going at it about droop, but it ended abruptly and I wish they had gone on.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ohjolt2 &raquo;</TD></TR><TR><TD CLASS="quote">Something i learned today. If you put one inch of pre load on to a 400 LBS. You now have 400LBS of pre load and it will take 400 lbs of weight before that spring/shock moves at all...</TD></TR></TABLE>

Springs being what they are, preloading a 400 lb/in linear rate spring with 400 lbs does not change the spring rate, or the continued displacement of that spring. The spring continues to have the 400 lb/in spring rate, regardless of how much it's been preloaded.

It doesn't take more Force/Weight to displace a 400 lb/in spring 1" with 400 lbs of preload than it would for an non-preloaded 400 lb/in spring. Until you get to the point where the spring has been preloaded so much that it runs out of travel and the spring constant becomes infinite, it's all the same.

The Model that you propose doesn't make sense to me in that the preload and the real load may exert a total of 800 lbs of force on the spring--however that 800 lbs of force will simply displace the spring 2" instead of 1" for a single 400 lb load. Since we're talking about adjustable ht. coilover setups, the extra inch of displacement could be compensated for by spring perch settings.

Basically, if you have a suspension with 400#/" springs w/ a) 400# of preload and b) 0 lb of preload, in a dynamic situation where the springs are being compressed, they will act the same.


edit-The rest of your post makes sense, the 2nd time around

 

I never said it was a good idea i was just using an extreme to illistrate that preload does mean something. Also from what i remember from my simple mechanics class the LCA's are going to amplife the weight on the springs. Imagine we turned the car on its roof and replaced the spring/shock with a scale. Now if a sit 100LBS on the shock mount of the LCA the scale is going to real exactly 100lbs, but if i sit that 100 lbs on the wheel with a 1.5 wheel rate the scale will read 150 lbs. Think teater toter if you have to. Just like putting a pipe on your wrench will give you more force to break a bolt lose.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bad-monkey &raquo;</TD></TR><TR><TD CLASS="quote">

Springs being what they are, preloading a 400 lb/in linear rate spring with 400 lbs does not change the spring rate, or the continued displacement of that spring. The spring continues to have the 400 lb/in spring rate, regardless of how much it's been preloaded.

It doesn't take more Force/Weight to displace a 400 lb/in spring 1" with 400 lbs of preload than it would for an non-preloaded 400 lb/in spring. Until you get to the point where the spring has been preloaded so much that it runs out of travel and the spring constant becomes infinite, it's all the same.

The Model that you propose doesn't make sense to me in that the preload and the real load may exert a total of 800 lbs of force on the spring--however that 800 lbs of force will simply displace the spring 2" instead of 1" for a single 400 lb load. Since we're talking about adjustable ht. coilover setups, the extra inch of displacement could be compensated for by spring perch settings.

Basically, if you have a suspension with 400#/" springs w/ a) 400# of preload and b) 0 lb of preload, in a dynamic situation where the springs are being compressed, they will act the same.


edit-The rest of your post makes sense, the 2nd time around </TD></TR></TABLE>
OK i never said the rate would change because i know it wont.
What i am trying to say is this if you have 400 lbs of pre load it will take 401 lbs to start moving the spring. If you take the spring/shock out of the car and put 400 lbs of pre load on it you can start stacking weight on the top of that shock and it WILL NOT COMPRESS untill you get to 400 lbs.
This of it this way. Imagine a big *** play ground teater toter. Say i put a fat kid on one end, the other end goes up. now i take that other end and chain it to the ground with a 2 foot chain. the fat kid is off the ground now and the chain is holding the free end from flying up. Say my fat kid weights 400 lbs. If i sit a 200 lbs kid on the chain end do you think that fat *** one the other end is gonna move??? NO its going to take a 401 LBS fat kid to get that chained end of the teater toter to move down.

 

I understand that the LCA's provide a kind of negative mechanical advantage at the wheel over the shock mounting point. But this won't affect how much the spring is compressed under the weight of the car. 500lbs on the spring is 500lbs on the spring, and will compress the spring accordinly, no ratios need to be applied to find this.
Wheel rate is a product of the motion ratio, and afaik is only used to tell how much of the spring's effect is actually reaching the wheel.

 

It has too, your springs are going to think the car is heavier than it is. The machanics of it goes bothways. If you could run your springs even with the wheel then it would be a perfect 1:1, And for a 500 lbs spring and a 500 lbs cornor weight you will get one inch of static compression, But if you moved that spring in to say a 2:1 then the spring is going to compress 2 inches on the same car because of the mechanical advantage. the best way to look at this is the way i mentioned earlier with fliping the car on its roof.

 

I think we are talking about the same thing, different side. I'm talking about the compression of the spring itself; not the height of the car. 500lb/in spring, apply 500lbs, get 1" of compression.