I know, but i dont technically know. Get what i mean... or even this statement...

.. This is what i was talking about... Maybe you guys can point me in the right direction, where i could read up on stuff like this... Something that covers every aspect of a suspension, but that also gets really detailed as so i could understand what you guys are talking about. Id like to understand how shocks being to tight or not tight enough and which rebounds id look at. Be it my current car or any in the future that i build. I hate not fully understanding everything and not bein able to speak on the same level as you guys.. I dont want parts just for looks, believe it or not, im just a really technical person with everything i do. So i'll ask this, What can i read that'll cover a whole suspension... From springs to sway bars to stuff as specific geometries of raising and lowering the car and LCARB's. I think if i could possibly find a book(s) that get that detailed i could read about the stuff im askin so i dont have to ask you guys every little question i have, only the stuff i dont get. A guy told me that with as many questions that i have i'd take years to answer them.. So VETRUCK or AM91Camaro_RS or anyone, whats some good reading to look at? I think that'd make it easier on you guys not having to deal with me everyday. LOL.

 

Try Bilstein struts or red Konis for front struts.
Front springs from a V6 third gen should work good for you. They'll be better drag springs than springs from a V8 car, and with a V8 they'll lower your front end an inch or two. And the best thing is, you can get them for free or just a few $.

 

weaz,

Chassis stiffness is everything for a good baseline. When I say "chassis stiffness" I am talking abount the mount or pivot points the suspension mounts to the chassis in all four corners being 3 dimensionally rigid and never flex.
Why?
Because when they flex, the tire footprints change on the ground and alter the grip size and balance on each individual corner.

Then we go to what actually hold up the chassis? The coil springs. Static is motionless, dynamic is in motion as in braking, cornering, or acceleration or a combination of two. The LEADING edge of that motion has generally two tires (not the motion of the car, the motion of its chassis/body weight transfer) That leading edge in a left corner would be both right tires. That leading edge in braking would be the two front tires, that leading edge under throttle would be the two back tires.

So now the question- what about braking to the left? Well, it starts with the two fronts and stays on the RF as the LF moves motion weighting the RR tire. That transfer forth and lateral is where the sway bar assists handling the motion and balncing it so as thte RF does not take the blunt of the force. Wheel base (length of the car also assist fore and aft as an invisible sway bar so to speak through leverage acting the same as a sway bar acts laterally, the wheel base acts longitudinally.

So how do we use spring rates? The higher the rate the more the motion weight will rest on that individual tire.
This has to be understood that the front of the car most always is heavier so you have to start out statically with heavier front springs than the rear to control its heavier nose from braking nose dive, and from the chassis diagonally rolling over onto the front outside tire in a hard braking corner entrance.

So now, think of the front springs controlling braking force.
The rear springs control acceleration force.
And the two (front and rear in blance) need to be balanced to maintain a decent cornering force laterally giving chassis weight balance to both outside wheels. If the rear is sliding in a corner, the rear spring rate is probably too high and the weight load is motioning more weight bias onto the rear than the front tire in balance. You sither raise the front spring rate, or lower the rear spring rate (there is so much more to this, but I am just trying to keep this as basic for now so you understand basic spring rates and how they work controling the chassis weight on each wheel.)

 

So how do we end up with the right spring rates? Its all based on the individual car's chassis weight and roll centers (Imaginary points in the front and rear suspension plains that determine where the body motion rolls on.) This is ficticious leverage points that can and generally will be different on every car based on each car's individual ride height and aftermarket conponant additions. {its why you just can go off of someone elses spring rates on their car. You can get a close estimate to start with, but your optimum will differ based on your individual choices right down to tire size, brand, and rubber coumpound. Tire sidewall HAS SPRING RATE. Different tire that the next guy? different suspesion needed...that simple)

Spring rate is determined by body roll degrees- most of the time it is about 3* at max traction.(This can and generally is much higher in an average street car) Lets say you want around 3* body roll at max traction and that sets the outside suspension at 2" compression in the corner- thats our desired body roll,...BUT...we find out through checking shock travel indicators in skid pad testing that the car is loosing traction at 2 1/4* lateral roll. We have too stiff a car and are loosing mechanical grip of the tires due to the suspesion being to abrupt or hard on the tire when loading them laterally and the tires are shocked or loaded drastically bouncing them to where they are taking the blunt of the road imperfections rather than the suspension absorbing road imperfection and the tire sidewall and contact patch staying optimum and maintaining max grip and footprint size without distrorting or overloading unweighting too much off the inside tires either.

So spring rate is determined by how much body roll you desire. Cadillacs (olders ones) are not know for their cornering abilties, they are known for straight line comfort. You turn them hard into a corner and the sway badly obtaining maybe 8* body roll. Now you swerve back the other direction and the chassis has to go from 8* left roll to 8* right roll. Thats a long way and a long time in transistion, but soft and smooth going over straight line bumps compared to the car that only rolls 3* left and right.

Now we get to shocks (And or struts- same basic thing for all you need to worry about for now) We are merely concerned with them as a damper, not as a suspension piece. Shocks control dynamic motion of the body, They slow that body movement. The body will eventually still get to 3* roll, but it will take longer to get there with higher damper rates. Too high of rates again shock load the weight of chassis motion onto the tire sidewalls distorting the contact patch, not enough willpromote too much chassis roll and pitch and slow the chassis motion response towards te direction you point the steering wheel. You have to find ths balance of shocks with spring rate and chassis motion rate.

So what shock damper rate? guessing game again. Most manufaturers whave prevalved shocks for the individual use you desire. So be it comfort, spirited street driving, or drag race use is the three common choices. You can not have all in one unless you go adjustable AND learn how to use them. There is more to just simply adjusting shock dampers to go from road racing to drag racing, Like I told you in a PM, it just can't be done. You need to pick what you want the car to do and stick with it. A drag car suspension will always be dangerous on the street at freeway speeds because the front springs are soft in rate and the front hock damper has to be very low in rebound force & high in compression force compared to a regular needed street or road race type damper.

That was long, but I hope well appreciated and understood. You have alot to learn and I commend you for eanting to, suspension dynamics is facinating, but VERY VERY COMPLEX- you will not learn this over night, nor will you learn this in one year. It takes many years and lots of on hand experience. All the bookworms in the world can give you a mathimaticall scientific suspesion setup on paper, but I GAURANTEE YOU I do not care who they are, you will still have to take that setup to the test track and shake it down fine tuning it. That my friend is why ALL the big sprts car manufacturers have high speed test tracks and secretly test and test and test again.

This is not an easy game. Even the top level NASCAR crewcheifs making million dollar plus salaries scratch their heads at times.

 

lastly, what is a good suspension at night in cool weather will become stiff and terrible during the day in hotter weather and hotter asphalt.

During the days heat,the asphalt being hotter makes a tire build more heat and loose tractin quicker. That quicker loss of traction will mean less body roll. The suspension needs to be softened on hotter track surfaces. to maintain body roll and mechanical grip.

{just a last note to make your head hurt....}

 

Understood.. That will take me reading it a couple of times ... Appreciated... More than you can imagine... I value your opinion. Ill have some questions after i read your long post, N i think my head will definitely hurt.. Ill get back to it when i have a bottle of aspirin in hand . ... Heres a question though... I talked with Spohn about their R&P and i decided to ask about spring just to see what they'd say. N whoever i talked to said that with the drop spindle (2") i wouldn't need different springs all around, but one of the guys here said id need 2" shorter in back... So im curious, which is it? Same all around or shorter on the rear? I would think they'd be different seeing as the drop, drops the entire front... Right?

 

to answer where to find a K member I'd suggest PA Racing. I've seen this on a '91 RS and it fits very well with the pinto manual rack.

 

If the front of the car is dropping two inches by use of 2" drop spindles.....right? yes

Then how are you planning to drop the rear of the car the same to match the front?

You do not have drop spindles for the rear...right? So of course you will need to drop it somehow or esle the back will be higher than the front in proportion.

Some of you questions i really think if you just stop and think about it yourself you should be able to answer your own question here.

Of course you need a two inch shorter spring onthe rear if the front is dropping two inches in ride height. There is no other way to drop the rear to match the front.

Weaz, this is so basic of questions, I really think you should just drive your cr as it is. If you can not understand a simple liitle thing like needing stock hieght springs in the rear or two inch lower springsin the rear if you are lowering the front 2", Then you are in no way going to be able to know what you are looking at for install and setting and tunning adjustments of any modifications you make.

My 3 posts I wrote you last night are so remedial yet that makes your head hurt. I will say again now in public that I think you need to stop buying parts and start reading first. You questioning is very lazy. I am sorry, but it really borderlines the second grade level. I say this not to be mean (I have basically already told you this in PM's privately) but you need to just stop spending your money on things you know nothing about. You are so far behind the lkearning curve of suspensions and vehicle dynamics it is obvoiusly not your thing. To each his own, I am sure there are things you excell at where I know nothing- we all have are strengths and weaknesses. I will just end it by saying again, your questions are really silly and lazy. Its like you want us to drive to your house and hold your hand and build your car for you.

 

It wasn't a question, it was more so just saying that the company i asked who builds parts for our cars told me that, and not so much a question but a statement of disbelief. I understand about lowering the car. I was just joking, get it. Haha. I only skimmed through and was saying that i have to sit down and focus on understanding everything you wrote.. Granted everybody has their own things in which they excell, but thats like saying.. If your not born with the talent you shouldn't even try... I might not catch on as quick as you think i should, but im not gonna give up. This is something id really wanna learn, so if it takes me a year instead of a few months, big deal. Starting from the bottom isnt easy, i gotta work for it. If that was the case everyone would be successful. Plus i dont need anyone to hold my hand.. N i havent purchased anything else besides what i had mentioned before... I know your not being mean (but thats like a slap in the face) and i have no problem with constructive criticism, it probably frustrates you, as it does me... Thanks.

 

Ok then, lets simply take another look at your...um... joke...

Looks like a question to me, or just one bad joke that nobody got. I really took alot of time to try and help you and you insult my intelligence. Good luck.

Dean
ps- and also clown, I NEVER suggested you stop asking questions, I suggested TWICE that you stop buying parts until you gain more experience as to vehicle dynamics. The one part you bought is a pretty major error for a street car in my personal opinion. I clearly posted my opinion on running afermarket kmembers on street or road race type cars. I would only use one on a full time drag car seeing 0 street use- but thats me. So now you continue to ask and say you value my opinion when you clearly ignore anything I have previously posted. Why bother asking me then, just do it.

 

No.My joke was when i said cause you had said That was the joke. Now the part about the question that relates to the company i talked to, that was more so a rhetorical question... Just thinking out loud. Thats a little harsh. I do value it. So just because i had not taken one of your suggestions its a problem, i mean how hard is it to look past the fact that i got the k-member... Its here to stay.. It seems were arguing over one part, all these post with you and I going back and forth... Im done with it. Thats why i hate computers, theres no emotion and its hard to tell what someone may be saying.. In this case a misunderstanding.Again, my bad. So I wont ask you anything else, thanks for the helpful info up to date. Now time to move on and bring this thread back to what it should be in the first place, and possibly something that might help others that read it... Thanks.

 

Few questions. With a 2" drop from racecraft spindles, ive looked around but havent seen springs that would match a 2" drop in the rear. Anyone know of any brands that drop the springs that i could get with the stock height up front and the drop in the rear..? Cause the dropzone is 1.75", hotchkis is 1" and the eibachs are 1/1 to 1.6/1.3...Also n e one know if the racecraft spindle is sold somewhere else for cheaper???

 

You're not going to find a company that mixes and matches a "drop" set, i.e. stock height fronts with 1"+ drops in the rear. Some company MIGHT do that for you on a custom order but you'll be calling and talking to them in person on the phone and will have to be VERY clear as what you want so you can avoid any return fees because they didn't send you what you wanted. I'm not even sure any of the companies besides someone like Moog even offer stock heights for our cars anymore. Hotckis, Eibach and the rest only offer drop sets.

 

Do you already have the spindles? If not, just get a set of lowering springs..... save a lot of headache.

Modify the stock springs? (I can't really recommend this method, unless you find someone that KNOWS what they are doing.)

 

With a 2" drop spindle up front, I'd almost think you'd want to LIFT springs. I'm at about 1.75" drop on Ground Control weight jacks & while 1/4" ain't much, I already hafta to think about driveways & speed bumps/parking lot bumps. Not even sure I wanna go much, if any, lower. My nose is JUST OVER parking curbs, which is always a good thing in 'bird, since we can't see the front end of our cars like the Camaro drivers.

 

That is why I like weight jacks. Other than alignment issues (with ANY lowering/lifting), you can change the ride height a will, within a (about) 3" range.

 

Cutting your stock springs was a piece of cake. Just use a 3.5" grinder with a thin (1/8") cutting wheel & DO NOT use a torch. The key is to keep heat as low as possible.

The ones I've done in the past, then used in autocrossed cars, I set the spring in a 5 gallon bucket of water, with only enough sticking out to cut. The water helped to disperse the heat & they were perfectly cool to touch right away.

 

No spindle yet, dont have anything yet just trying to figure out what to get so i dont have to return anything.. The reason im talking about the spindles is because they have the steering knuckle modified and thats what i'd need since im going to install a pinto rack. I dont want to lose the turning radius. Plus i thought that the spindle is better v.s. the lowering springs since it keeps the geometry correct.

 

for a street/strip car, that front end geometry won't mean anything to you. If you're building it for cornering, its a different story. Look at "circle track" parts suppliers for springs, there's a huge variety of diameters, lengths and rates available.

 

Whats the info on stock springs? Height? Rate? By that i mean originally on the caramo (factory). Cause most companies base their lowering height off the stock number..Right? Could someone tell me what that is por favor.Cause one site i glanced at has like 5/5.5' X 9.5/11/13/20'...

 

why not just go with a coil over set up..that way you can play with it 1" to 2" at a time.?

 

That is why a weight jack setup is so nice. That & they is cheaper, easier to install & introduces nothing extra, to limit the front tire size.

 

Cause i already have the Spohn k-member/a-arms for stock coil location. So weight jacks will let me adjust the front spring height, right? Say i got a 2" drop spindle, id either have to get a 2" spring for the rear or a 1.5" drop then cut it. Ideally i need a spindle with the modded steering knuckle because of the rack and pinion, and the only ones ive seen drop the car. I asked Sinister Z about his, he uses a Beltech, but i havent seen those for a camaro (new).. I know i may repeat the same crap over and over, or state the obvious but bare with me.. I'll state what i understand then we'll go from there... From what i understand dropping via springs isnt ideal because it changes the geometry of the front a-arm, so spindles is the way to go. With a 2" drop spindle up front i could use a stock height spring or a 1-1.5" drop spring with a spacer to bring it back to the ideal geometry (for the a-arm). Then i'd either have to find a 2" drop spring in back or get a 1.5" drop spring in back and cut it to get that extra .5". I dont get how weight jacks would fix the problem without messing up the a-arm angle, unless theres something im not understanding... Thanks for putting up with me guys. I bet im a pain.

 

Or what's ur guys's opinion on this... http://www.summitracing.com/parts/CM...8/?image=large . The shocks and struts are adjustable to like 90/10, 80/20, 60/40, or so i was told. The spring rate says 250 lbs./in. I remember 91_5.7_TPI saying i should try with springs rated at 800/850 for the front, or are the numbers he posted in different measurements compared to the 250 i had stated?

 

This is why im on here askin the same obvious questions and having people give me crap about it... Earlier in the thread Gregsz-28 said.... Based on that i was under the impression that i had to get a spindle like what //<86TA>\\ said... Today i was told by Spohn that with their R&P i wouldn't need spindles with shorter steering arms because their R&P is built to address that issue. How's that work?? Is that possible? So yet again i have to keep going back to stuff thats been already addressed. Not sayin i dont believe you guys, it just i keep hearin 2 different sides.. Sorry about flip floppin back and forth guys. Id like to hear your guys' comments on this.

 

typical rack and pinion setups dont have enough travel to retain the stock turning radius, you need something around 6" of travel, most racks top out at 3.5". If spohns rack has the needed 6" or so of travel, you wont need the shorter steering arms.

 

Interesting... I'll have to ask them.. This is what it says under the description... Pinto manual rack has an aggressive gearbox (3.75 turns lock to lock). Not sure if that gets me the travel you mentioned. Just though id throw that out there.....Thanks....

 

thats just how many times the steering wheel rotates lock to lock, nothing to do with travel.

however, 3.75 is a slow ratio, slower than anything offered in a 3rd gen. In a drag only car ot wouldnty be a big deal, but in the street, in parking lots, k-turns, ect, you will be turning the wheel a lot more than you are now.

 

How do i know what the spring specs need to be? Here are the different specs ive seen...5 x 9.5 or a 5 x 11 or 5.5 x 11 or 5.5 x 9.5.

 

Could someone please tell me what specs are on stock springs (92 camaro) so as i could figure out which ones i need to get the right ride height. How am i supposed to figure out what springs to get. Like is it better with a thinner wire diameter and more active coils or a thicker diameter with less coils? N whats up with the lengths, 9.5", 13", 20", how do i know what i need?

 

Anyone? Someone know where i could look to find these specs?

 

You can find those s[ecs on the existing coil springs in your own car.

Ever thoughtt of that being a good starting point?

You don't know your ride height.
You don't know your existing spring rate.
You don't know what new rate you want.
You don't know what ride height you want.
You don't even know what you arebuilding your car for what purpose other than wasting your money making mistakes.

How can anyone help you with your questions when you do not even know how to ask them properly and know what info to volunteer showing you are worthy of someone taking the time to help you calculate everything to an educated guess.

I certainly can't help you or even begin to know how to answer your question they way you ask them, how do you think anyone else can.

Thats why you are not getting any response.

Stop being lazy, go measure your own car.

 

he just wants someone to tell him what to do IMO.



look weaz, either 5 or 5.5" springs will work.
depending on what model you have, your stock front rate is between 450 and 750 lb/in
however, in MY OPINION, you should just KEEP YOUR STOCK FRONT SPRINGS!!!!!
get lowering springs for the back, but dont lower the front.
if you are going to buy new springs, at least get a worthwile spring rate.
some may disagree, and maybe its just the jew in me, but if im going to spend $250 on four custom springs, i am NOT going to go from 500 lb/in to 550 lb/in... just a stupid idea to me.
i would at least make a worthwhile change... meaning at LEAST 25%, or else you wont notice a difference
this is all assuming you are NOT vetruck and just want a car that looks good and rides good... not great, but good.

if it were me, i'd start by doing some math.
the basic equation of a spring is F=KX
F is force
K is spring rate (lb/in)
X is compressed distance

so, if you have a 13" stock spring with a rate of 500 lb/in and a certain weight on that spring, it will compress a certain ammount. PERIOD. this number is X
subtract X from your free height (13") and you have your installed height, or remaining spring length... however you want to look at it.

now, you want a stiffer ride.
OK

first, pick a spring height that is commonly offered.
lets say 9"
find your installed height from the previous example... lets pretend its 7.75"
9-7.75 = 1.25"
this means that if your 9" spring is allowed to compress 1.25" you will be at stock height.
if you want stock height then keep 1.25... if you want to lower your car, then make your 1.25 bigger... just remember that for front springs, every inch you add to 1.25, the car will be 2" lower... this is because of where the spring mounts in the suspension. for your back springs, its a 1:1 relationship
just for fun, lets make the new number 1.5, giving you a half inch drop in height.


now.
go back to the formula F=KX
you have your X... 1.5
you have your F... same as previous example for stock height spring.
F/X = K
solve for your spring rate and round up to the next available size...
meaning that if you calculate that you want 822.445 lb/in, 825 or 850 is a good place to start

 

I have but when i bought the car it didn't have stock ones, for your information it had Hotchkis springs. Your right i dont know a lot of things, but im trying to learn. Maybe i should go smack my parents and ask them why i wasnt born with this knowledge as it seems you believe a person starting off should already be on your level. You need to get off your high horse. N im not lazy, im making an effort, ive purchased books to try to learn. I cant measure off my car as its stripped bare. You may be really smart, but your rude. Plus i though you werent going to reply to my ?'s anymore? If your going to be postin and taking shots at me, then stop filling up my thread. Thanks. Now as for what Red_Dragon_85 said. (next post to come)

 

Okay so a 13" stock spring with a rate of 500 lb/in and a certain weight on that spring (lets say 600 for the rear). So in this case it'll compress 1.2" and the installed height would be 11.8", sound right? Now is that the original stock height or is that a new stock height? Not sure how you calculate that, so say it was 2 instead of 1.25 then how much lower would it be? Would it be that every inch i add to 2 it would be 3.2" lower? Is the front a 1.6:1 ratio? Continuing on. So with a 9" spring and a 500 lbs/in rate to compress it 1.25" id need 625 lbs of weight on it... Sound right? So now say like you said, we use a 1.5 drop as a new number.. I plug into the formula. In the previous example i got an F of 625. So that would give me a rate around 937.5. Sound about right?

 

you are getting confused.
1.2" is your pretend baseline spring compression when weight is added...
if you add half an inch, the car will sit one inch lower.
the reason for this is the way the spring sits in the a-arm in the front suspension.
so if you add half an inch, the car will actually be an inch lower.
1.2 has nothing to do with your ride height... its just a means to get to your final answer which is: what spring rate do i need?

 

So regardless of it being a 1.2" or 2" baseline spring compression, every inch added is a 2" drop... For the front. Just though id throw this out there, called Moog cause i was curious what the stock spring specs (for my car) were and heres what i got. Fronts are a 15" Free length, 11" installed with a 424 lbs/inch rate and the rears are 15 5/8 free length, 10 1/4 installed with a 109 lbs/inch...

 

so in that case your number would be 15 - 11 = 4 in the front
instead if my fictional 1.2...
and 5.375 is your rear number

 

One more question as far as the front lowering goes. You said that adding an 1" its lower 2" so with the stock specs i had posted that means the spring would now be a free length of 14" and installed 9" or just 14" n 10"? Sorry if im not getting this.
Was also curious if theres a formula that takes the front and rear rates, that can determine with the weight transferred to the back from a dead stop whether the springs in the rear are too soft/ stiff? Or is that something ill just have to mess around with once things are installed?

**** 1 other side note, //<86TA>\\ had stated... For anyone thats curious, i was just told that the Spohn rack has 5" of travel, so i guess no drop spindle is in order.****

 

as far as a program to tell if springs are too soft or stiff... nothing that I know of. there are soooo many other things that play into that. trial and error.

 

go back and read my post again.
its spelled out very clearly

 

Weaz, I am rude because you ask what spring we have and I suggest to you to simply go out and measure your own car? And then I find out it is even easier for you becasue youyr springs are already out of the car. Was I wrong to say you are lazy to ask instead of measuring your own car rther than asking here to others to measure their springs for you..Partner, you need professional help

Red, I wil try and work your equation. I am curious how well your equation works, lets see what we get:
F=KX

Then lets take Weaz' front and rear #'s and plug them in.
Front first-
F= 424(4)
F= 1695

Then rear:
F=109(5.375)
F=585

You would say at stagnant height the car weight (force) acting on the springs is 1695 front and 585 rear equalling a total unsprung weight of 2280. That leaves a 3330 lb car with 1050 lbs unsprung weight. That gives about a 3.33:1 unsprung to sprung ratio. I would say that is probsably close so far-We have heavy suspensions.
Lets go further-

front to rear "sprung" weight bias would be 69/31 %

Now we know an average V8 3rd gen to be aprox 59%/41% bias
(Reference facts- https://www.thirdgen.org/forums/susp...t-invoice.html )

that would mean the aprox 1000 lbs of unsprung suspension weight (consiting of the wheels, tires, axle housing and assembly, TQarm, LCA's, Shocks, Struts, Swaybarss, brake assemblies, coil springs, driveshaft, etc... in part or full percentages based on motion and mounting) would in retrospect end upon a 3330 lb V8 car as:
3330 x 0.59=1965 lbs front weight

So, 1965 total front weight - the 1695 front 'sprung weight' would leave 270 lbs front sprung weight and a whopping 780 lbs rear unsprung weight. This does not sound correct. Even though the rear sus[pension consists of the axle assembly with brakes, the Tqarm in part (not full TQarmweight because of mounting position and pivot ratio), same with shocks, swaybar, coils, LCA's, full weight of wheels and tires on rear. I just do not think they are over about 650-700 lbs and the front wheels tires, and suspension assembly in ratio to be more like 350-400 range with struts, coils, spindles, brakes, swaybar, a-arms, steering linkage in part, front wheels and tires, and misc other front suspension peices.

The formula F=KX is close, but I do not think close enough to caculate spring rate changes when based on lack of info until you buy and test new spring installed height. How do you know what any uninstalled spring height would be unless you test it with trial and error to see its height once that 1695 lbs front weight is placed on it WITH real world articulation bind and the correct spring to wheel ratio of 42%, not 50%.

To take one full inch of ride height off the front of the car WITH factory scrub radius and alignment you will attain a .42 inch coil spring cut at compressed spring height prior to cut. On a 450lbs spring at free height 15", that compressed (4") and a cut of .42" at compressed height could be (hypothetical guess) a .57" free height cut.

BUT, that same .42" cut on a compressed (2")height spring(to 11") cut on a 850 free height 13"spring will be in comparison to the above approxmation of a only a .48" free height cut. Cut this spring the same .57 and the drop at installed height would be 1.18" or almost 1 1/4" instead of the wanted 1"

Now once it is cut, you have fewer circumferance widings of free coils so the rate of the cut spring increases ever so slightly and wil not drop that exact 1" as desired. Each spring rate and cut off from that free ehight and rate design will vary and will have to be a trial and erro to get the stagnant ride height perfect.

There is no exact scientific formula. It is a trial and error to get the eact final results. It is a guessing game. You would have to ask everyone here to give exact chassis bias, exact tested spring rates on a spring rate testing machine, shock gas charge lift on each individual condition and brand of shock and strut choice, scrub radius and tire contact patch centerline based on alignment- this affects leverage of suspension of spring (the aprox .42 spring motion ratio) etc.

This is why you can ask someone eht they have, you then copy them and are slightly too low and thing ..."well damn, they lied to me". No they didn't, your cars are different.

Spring rate and free hehight choices are and indicidual trial and error thing. Both in stac AND THEN more importantly in Dynamic proportions front to rear in choice and desired final outcome in compressed/static ride height.

 

i think you misunderstood what i am saying vetruck
its simply a way to guess at a spring rate and length combination to get a certain drop...
im not sure where you get 1050 pounds of unsprung weight, but thats way too much IMO.
its acutally a lot more basic than you are making it seem.

take the force on the spring, and the spring rate...
you will get a certain change in length... its a fact. a 100 lb/in spring will compress 1 inch under 100 lbs... of course the first hundred pounds will only compress about .8" because of coil bind, rate creep, ect, but the average will be 1 inch per 100 lbs...

of course trial and error are the best ways, but if you just want an answer to the question of "i want to lower my car x inches, what spring do i need" this method will get you close.
and for some people, close is darn tootin close enough. get what i am saying?

as for the motion ratio, 50% is a good approximation for generic a-arm type suspensions if you dont know better, 42% is better, and more accurate, and i will tell people 42 from now on.


vetruck, i realize you have a lot of knowledge and are good at helping people, but really, do you think getting it perfect matters when he cannot comprehend simple things like needing a 2" drop in rear suspension height with 2" drop spindles?
all i am doing is giving an approximate answer that will suffice for people who simply want a lower car that rides good




edit:
i went back and looked again.
it makes sense what you are saying, and your front weight numbers seem to agree with what i remeber calculating before, but my numbers also turn out much more... normal.
also, i am skeptical of the front rate being so low.
i did most of my calcs on 750 lb/in springs, and although the rate is higher, the total force is the same if the car does not change

 

Thanks for the explanation.... I had a question... With a bolt on 98-02 rear for a 82-92 camaro, would parts for the rear, shocks,springs, LCA be ordered as 98-02 or 82-92?

 

Shocks, springs, LCAs & PHB are all the same fit, from 82-02.

 

thanks

 

4th gen shocks will fit, but make sure you use third gen shocks, since they are valved differently.

 

Valved differently how? Also, are you saying that based off of stock or does that apply to anything... be it all stock or all aftermarket suspension?

 

Just thought id throw this out there and here what you guys have to say about this... My K-member has the 71-72 Pinto Rack mounts and the specs on the manual rack are 3.75 turns lock-to-lock; rack travel 5.25"; overall length 45 1/2 inches. Then theres the 74-78 Mustang II Manual Rack & Pinion which has the specs 4.00 turns lock-to-lock, rack travel 5.25", overall length 45". The Mustang II is only a 1/2" shorter.... The reason i brought up the Mustang II Manual Rack & Pinion is because further down the page theres the Mustang II Power Rack (16"). It says its dimensionally interchangeable with the 74-78 rack... So i was curious to know how much work would i need to do to make it work? Probably where it mounts on the k-member and what else? Here's the page i was looking at... http://www.fastpts.com/cgi-bin/hazel...frrackpin.html

 

Sorry I don't have an answer to your question, but for simplicity, I would just use the pinto manual rack. It really isn't that hard to use manual steering, and it should be easier to operate the rack than it is to operate an S10 manual box. I doubt that anyone here has used a Mustang II rack unless it bolts directly in place of the pinto rack.