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 Post Posted: Mon Feb 02, 2009 11:19 pm 
 
That's interesting my anti squat is at 106.2 percent i can move my bars one hole and it goes to 98.6 percent witch should take some hit away and should be even faster in the 60 than it is now.
I will make that change and see if it does.


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 Post Posted: Tue Feb 03, 2009 9:56 am 
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Scott Smith wrote:
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Dave Morgan suggest's using the lightest spring possible and use the adj. collars to get what you need for a spring rate, and have some stored energy,


That's old school and incorrect.
On a front end of a nose heavy car that needs help pitch rotating yes.

But on the back of a car no. Ken's been there, he knows!  :-$


So this is what would help MY nose heavy elky then, hmmmmm, good info Scott, thanks for correcting me ;-)  

It just seems that for each of our chassis's, we all want the same thing, the most traction possible, the lowest 60ft. et, and the least amount of wrinkle in our tires to obtain all this for our best result in et, and. each chassis will be different due to front to rear weight bias, torque to work with and where our I/C is in relation to the nuetral C/L, above the nuetral line gives you more antisquat, and below gives you less antisquat right?, and we all just need to find the balance point for each chassis then, hmmmm, very interesting.  So Dave still uses some old school teachings probably because it is in his book currently out there than for using on older technology?  This is some of the things people have said about his teachings, ok, now I get it...reality tells all then.

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 Post Posted: Tue Feb 03, 2009 10:39 am 
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Elky,

I don't think you can change the spring rate with the adjustable collars, just the ride height.  

The spring rate is built into the spring at the time of manufacture, and may decrease with time and usage, but is not adjustable.  

That's how I understand it,

Donee


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 Post Posted: Tue Feb 03, 2009 11:28 am 
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Slowpoke wrote:
Elky,

I don't think you can change the spring rate with the adjustable collars, just the ride height.  

The spring rate is built into the spring at the time of manufacture, and may decrease with time and usage, but is not adjustable.  

That's how I understand it,

Donee


Donee,  I am going to try to understand this and send you a thought also and tell me if I'm wrong or not, once you select a spring for your application, it should be for your weight of the vehicle on your springs & shocks and the length needed right?, to get the correct amount of support per your torque applied depending on how the rear suspension is set up.  Now, if you get a spring, and it needs to be compressed 2 inches to get your required rate of(let's say 200lbs.) needed for your application, and then you find your ride heigth is off, what stops the chassis tuner from moving the shock lower mounts up or down in adj. to achieve this ride heigth desired?  Does this make sense?  The spring manufacturer knows how much compression a spring  has per inch of compression and this info is needed,  I know your chassis info is required to order the correct spring per your ride heighth and rate needed from the get go, but that sets the spring/shock package right? and let's say you forgot to add in your battery weight, or a larger/smaller fuel cell, and your ride heigth is not what you want then!, why can't you make the shock lower mounting location higher or lower for your desired heigth?  See what I mean here, you still have your support of the spring and the correct rate, now you just adj. for body heigth, right?   The only thing I can see that stops this is a non lower adjustment, then yes, I could see this as an issue of body heigth vs spring rate changes.  Any of this make sense?  I am still learning about this stuff and this is part of what I took from the seminar I went to this past weekend, and it seems t make sense to me, but then again,  [-(  [-(  as I have empty pockets =;

Ok, after doing some more info gathering,  once your shock/spring package is set up, you shouldn't use the lower adj. rings to adj for ride heigth as it will either shorten or extend your shock dimensions which have already been calculated into your package, you may run out of bump or extension travel.  Does this sound better? sure hope so, I need to learn this stuff ;-)

John

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 Post Posted: Tue Feb 03, 2009 12:12 pm 
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John, You need to set your shocks some where in the middle of there travel.

My shocks are set to 16 1/2 inches at ride height now that has nothing to do with if the spring is compressed or not... O:)  I have 125lbs spring on my car now and they are not compressed at all if I let the suspension hang....

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 Post Posted: Tue Feb 03, 2009 12:53 pm 
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John,

Most of what I think I know about suspensions, I read in, 1st Chris Alstons Chassis Book, 2nd Dave Morgans Chassis Book.  I don't agree with everything in those 2 Books.  Doesn't mean they are wrong.  

I've learned a lot from watching video of my car and talking to Scott Smith.  Hopefully he'll bail me out if I explain it wrong. =;  I've also learned a lot from reading post by Bubstr.  I think a lot of guys try and make this a lot more complicated than it really needs to be, just like the carbueration deal.  Scott and Bubstr, are both good at keeping it simple.  You can over think this and get way off base.

Basically, you pick your spring rate based on calculations, experience (yours and others), and/or trial and error, it has to support the car all the way down the track without hitting the bumpers (Right Ken?).  With the right spring rate you mount your shock/spring package to get the desired ride height (coarse adjustment).  The threaded adjustable collars on the shock body are for fine adjustment, and you have to make sure you don't run out of shock travel in either direction.  If you picked the wrong spring rate you have to change the springs.  The shocks control how fast everything happens in both directions, you have to have double adjustable shocks to have the control needed in both directions.

I hope this didn't offend anyone,
or confuse the issues,

Donee


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 Post Posted: Tue Feb 03, 2009 5:11 pm 
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Slowpoke wrote:
John,

Most of what I think I know about suspensions, I read in, 1st Chris Alstons Chassis Book, 2nd Dave Morgans Chassis Book.  I don't agree with everything in those 2 Books.  Doesn't mean they are wrong.  

I've learned a lot from watching video of my car and talking to Scott Smith.  Hopefully he'll bail me out if I explain it wrong. =;  I've also learned a lot from reading post by Bubstr.  I think a lot of guys try and make this a lot more complicated than it really needs to be, just like the carbueration deal.  Scott and Bubstr, are both good at keeping it simple.  You can over think this and get way off base.

Basically, you pick your spring rate based on calculations, experience (yours and others), and/or trial and error, it has to support the car all the way down the track without hitting the bumpers (Right Ken?).  With the right spring rate you mount your shock/spring package to get the desired ride height (coarse adjustment).  The threaded adjustable collars on the shock body are for fine adjustment, and you have to make sure you don't run out of shock travel in either direction.  If you picked the wrong spring rate you have to change the springs.  The shocks control how fast everything happens in both directions, you have to have double adjustable shocks to have the control needed in both directions.

I hope this didn't offend anyone,
or confuse the issues,

Donee



Donee, didn't hurt me, but this is the kind of info imo that get's out and confuses people, like myself.  The info I posted was pretty much right out of Dave's book, and reading how he set's a chassis up is how I tried to word it per his example.  Be it right or wrong, I just need to know the truth I guess and if there are many different ways to get the right end result, so be it, and I think there is many ways.  It's kind of disturbing that I keep hearing things about Morgan's ideas and setup theories and how he does things and then from what I read, it kind of confuses me as I don't have a chassis to try things out on and get a result to verify it, not yet anyway ;-)

I agree with you also that Scott uses the kiss theory quite well and most of the time it is understandable and I need more input,  and until I can get out there and try it in real time, I guess I should just keep reading and trying to learn from racers that are currently going down this path of tuning.  I need to work these ideas, settings and tuning theories in my head also, and without a chassis to physically play with and measure and so on, I feel a little dumb with some of this stuff and how to interpit it. :-   It kind of makes my head spin, like my tires have done last year & the year before [-(  [-(  [-(

I could disagree with you,  on your wording on selecting your springs, by taking other racer's advice only from the fact that this is exactly what Morgan says not to do!!!! since we all have different chassis's, none of them will be the same, close, but not the same.  And this is some of the info I am talking about.  I am not going to disagree with you for the fact that who, or what is right, correct, or will be the best for any chassis setup.  

What I would like to do, if I could afford to do it is, try it both ways, try Dave's way, and then try it the racers way, gathering what info I know from books, and from other racers input and see which get's me closer to the best setup! like a blind placebo test(spelling???) All I know is, I need to get it right if I can, the first time out, and I believe it can be done, but seems many guys have already been down this road also,so this backs up what you mentioned.   I apolgise if I sound anal in my thoughts, and may be looking too deep into this system of the chassis, but I want to learn as much as possible, and I thought I was doing ok with my junk, but I am still a rookie and learing.  I have learned more on what to look for on a chassis when it leaves the line and about 100 ft or so out, vs. what I have red and tried to comprehend as to what is actually happening vs. the theories written.  It seems like a roobic's cube to many, and I want to learn it a little easier than that group by all means.  yeah, I road the short bus, and on some things I AM slow with on the learning curve, but when I get it look out.

I also am agreeing on your shock info too, and when Dave was going thru the shock/spring setup on how to math it all out, it only gives a margin of about 2 inches of travel in either direction for our rear suspensions, and that seems a little tight to me, then I think of all the cars I have seen from behind and how out of control many of them are, it kind of makes sense on the better built cars and chassis's set up way better than say, a stock chassis like my Elky.  I just want to get it right on the buildup of my backhalf so I don't have to keep buying springs to find the best setup, but if that's what it takes, so be it ;-)  I think it can be done first time out, but I am sure I will be wrong again in this area :- , jmo though.

Thanks Donee, your info is welcome always as well as Ken,s Barry's, bubstrs, Scott and others on here, you all have been down this path a little sooner than me, and I need help O:)  O:)  O:)  

I think also, that I will get a few more books like Bickels, and a few other ones and read up on there technices and theories and then try to understand it all a little better, damn, this is wayyyyy tooo long of a reply, next!!!! =;  =;  =; sorry guys, I'll try to look outside of the box on this suspenson stuff from now on.   Just think of me like a sponge from now on ;-)

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 Post Posted: Wed Feb 04, 2009 12:11 am 
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I haven't read the whole thread so this may have been covered already.  If so sorry.

Keep in mind that the antisquat line is an estimation unless you know exactly where the center of gravity is.  With this in mind you may believe that you have an a/s value of 95% using the estimated a/s  line when in fact the actuall a/s may be 105%.  

Greg


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 Post Posted: Wed Feb 04, 2009 12:45 am 
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smoozer wrote:
I haven't read the whole thread so this may have been covered already.  If so sorry.

Keep in mind that the antisquat line is an estimation unless you know exactly where the center of gravity is.  With this in mind you may believe that you have an a/s value of 95% using the estimated a/s  line when in fact the actuall a/s may be 105%.  

Greg


This is good info. the rear will tell you your I/C squat is low and separation is high. You reakky want neither. I have a bunch of stuff to write here, but PC is acting up. I'll get it but keep an open mind on this subject.

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 Post Posted: Wed Feb 04, 2009 10:02 am 
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Somethings about springs, you should know. Spring rate is figured and checkedby compressing the spring one inch then zeroing the pressure gauge. You then compress te spring one more inch and read the increase on the pressure guage. Unless you have a progressive rate spring, this rate will be the same for any given inch of spring compression. Therefore, if we put 400lbs on a 100lb per inch spring, we can expect that springAnother variable is the shock. The shock does not stoptrans to compress 4 inches. This spring wouldthen store 400 lbs of energy, exerting it's force up and down. The law of motion that governs force, says for every action (force), there is an equal but opposite reaction (force). This force is what plants the tires.

Let's put this into practice. With a rear spring, we have 400lbs on it. We transfer 400 lbs from the front to the rear on launch. It now compresses another 4 inches to 8 inches and now stores 800lbs energy or force. This will remain till we run over a bump  or depression in the Track, or the front settles down, transfering that weight back to the front. One of the other variables is induced squat or anti squat. This is a mechanical force that works with or against the springs stored energy, not instead of, as we didn't remove the spring., so it is still in effect.  Another variable is the shock.It does not stop transfering or storing energy, it just modifies it. A soft rate shock allows a spring to receive, store and give up energy (force) very quickly. A stiffer rate shock will slow these processes. Although a shock doesn't change a spring rate, it can change the effective rate at the wheel. Yet another variable is limiting travel. Either a tall bump stop or limiting extention can  modify if a spring can store or give up energy.It can never store what it isn't allowed to compress and it will never give up what it isn'y allowed to extend. During compression of a stop restricted spring, it stops storing and directly transferes weight to the wheel, distorting tire at times.

So what it boils down to is how they recieve, store and give up energy. You can rest assured if you put 400 lbs on either, they will store and give up the same 400 lbs. It's just how they do it that makes them different.

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 Post Posted: Wed Feb 04, 2009 12:22 pm 
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I just read a thread on another site forum and a good point that also needs addressing when setting up your spring rats is srung, vs. unsprung weight.  Does everyone know how much your complete rear axle assmbly with brakes and fluid weighs?, the 4 link bars, track bar, wheelie bars if any, wheels and tires?????  this weight all applies to calculating spring rate also, and there is a calculaton that goes something like this, take your rear weight from the rear tires, subtract the unsprung weight, wheels, tires rear end, ladder bars, 4 link bars, shocks, spring/springs and so on from that weight you just took off the scales in the rear and split  half of that weight gathered of the components and subtract that from the total weight on the rear end and that is your sprung weight on the rear end.

example; rear weight=1232.5
600 lbs = rear component weight
600 lbs  (divided by 2) of component weight
300 lbs

So, 1232.5 - 300lbs = 932.5lbs, this is your sprung weight on the rear.

Does this info sound correct when calculating for spring rates?

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 Post Posted: Wed Feb 04, 2009 12:50 pm 
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That's why most drag racer have a few sets of spring laying around =;

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 Post Posted: Wed Feb 04, 2009 3:10 pm 
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Anti squat

Just because we see it in print, don't mean it's true. As a matter of fact. I don't even expect you to believe the spew I put out. Sometimes, I don't even believe me. But if it makes you think and lets logic and experiance form your opinions, then it's worth while. The article that Scott posted is how I believed for years. I was wrong. The article is wrong. Guess we all live and learn.

Physics plays a big partof racing. The guy that wrote this article must not have paid too much attention to the laws of nature. The one law that applies here is the law of motion. You don't have to be an Einstein to understand the law of motion. For every action, there is an  equal and opposite reaction. Our cars are loaded with actions and reactions (forces).

The first force that applies here is the forward force starting at the rear tire  contact patch.  Track is flat and tire rotation provides a forward force. Not up or down or any angle. This is the single biggest force we have as  soon as we exceed 1G because 1 g is the force we have holding the car on the ground.. These forces act on the center of gravity (center of mass). Where is the equal but opposite force? It's the car wanting to stay where it is This isthe other part ofthe law of motion. Things in motion, tend to stay in motion and things at rest tend to stay at rest. That leads us to where the center of gravity wants to stay.It wants to stay at the starting line, but can't because of a chassis connecting it to the other forward force. What is a center of gravity to do? Easy enough, if yougo straight there, you take the round trip and turn that rearward force into rotation. The front will go up and over but for counteracting force called gravity and the rear will go down as far as the ground will let it. This is what provides weight transfer. The degree of which is determined by power/ traction/ center of gravity locaton, but not by the instant center.

The instant center has it's own job. that is to create rebound or compression in the rear suspension. It lifts nothing but the rear of the car in an anti squat value. For it to lift a front end of a car, would be like me taking a 16lb sledge hammer between my index finger and thumb and lifting it to touch my nose with the head of the hammer. There simply isn't enough leverage to do this. The bottom bar pushes and the top bar pulls, but both are overpowered by the 1 to 2Gs of forward force acting on them.  This is the force that will determine what degree of compression or rebound you get. This compression or rebound will help or hurt you springs ability to apply pressure to the contact patch.



Now that I opend the door on rotation, lets look at another law of physics. The law of enercia or polar moment. Everyone that ever thought about trimming of a crank or the small diamerter clutch, a lighter flywheel or even lighter tires and  wheels has fooled with this law.It's the farther away from the center of rotation or center of gravity the more effect weight has on motion. Anyone that has been on a merry go round knows it's harder to stay on the farther you are from the center you are.  It's like you weigh more the farther away you are.You do when in motion. It's centrifugal force This iswhy high or low weight is ever bit as important as front or rear weight. High weight has more effect on motion than low weight. Front weight needs to be rotated and rear weight doesn't.

I know there is always more than one way to skin a cat. When we make it work it always agrees with Physics. If it doesn't, it probably didn't work that well. Then there are times, we just don't see the link.

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 Post Posted: Wed Feb 04, 2009 4:52 pm 
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Beretta wrote:
John, You need to set your shocks some where in the middle of there travel.

My shocks are set to 16 1/2 inches at ride height now that has nothing to do with if the spring is compressed or not... O:)  I have 125lbs spring on my car now and they are not compressed at all if I let the suspension hang....


 How much does your car weigh in at?  How much of that is on the rear tires?

Don

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 Post Posted: Wed Feb 04, 2009 6:33 pm 
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want-a-be wrote:
Beretta wrote:
John, You need to set your shocks some where in the middle of there travel.

My shocks are set to 16 1/2 inches at ride height now that has nothing to do with if the spring is compressed or not... O:)  I have 125lbs spring on my car now and they are not compressed at all if I let the suspension hang....


 How much does your car weigh in at?  How much of that is on the rear tires?

Don




Don, my car weighs 2135 race ready without me in it. With 1020 of that is in the rear...Why do you ask???

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