In fact a table of springs and shock rates will get us in the right way of suspension tuning for J-Bodies in the future. I have many cars with nothing more than a sport tuned suspension and are many seconds faster than the stock ones in the track and the street. Remember that power is not always everything.
Other comparison, remenber that execelent suspension names like Ground Control and Tein uses something like 3xx/3xx or 3xx/2xxx for their J-Body coilover suspension products for the street. Then going harder seems to be innecesary.
Thanks,
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The numbers that have been posted for the stock spring rates seem to be way off. I don't think they are that high. I would guess that the rates of the factory Z24 springs are somwhere around the rates of the Apex springs.
I got these replies years ago from various companies.....
Reply From Apex:
The spring rate on the front is 152# in front and 115# in rear. Let us
know if we can help any more,
Apex Sales
Reply from Eibach (Pro-Kit):
-Is this application a progressive or linear rate spring? PROGRESSIVE
>
> -What is the spring rate (front and rear) for this application?
THE SPRING RATE VARIES FROM 154-200 IN THE F
TO 69-151 IN THE R
Reply From Eibach (Sportlines):
The front Sportline spring is progressive with a 1st rate of 122lb/in
and a 2nd rate of 225.47lb/in.
The rear Sportline spring is also progressive with a 1st rate of
58lb/in and a 2nd rate of169.73lb/in.
I have sent an email to H&R springs and Koni to get more info about rates. As soon as I get the info, I will post it here to share with you. If some of you can confirm OEM spring and shocks rates, will be great for comparison purposes.
I think that this is the best way for people to choose the suspension appl for their needs, street, track weekends, racing, etc.....
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I still haven't gotten the rates from Sprint, but I can say this. When I got the springs everyone said they have a really high spring rate, maybe too high for a Cavalier, especially a daily driver. I've noticed it's a firm ride, but with the D-Specs turned up about half way, I find the ride to be quite managable for normal trips around town and taking the car on road trips isn't as bad as I thought it'd be. Some bumps hurt a little, but no more than they did on the stock suspension. The body roll is almost nonexistant compared to stock, there's hardly any dive under braking and the squat under acceleration is pretty much gone, I can't even get the tires to break loose because the weight of the car just doesn't transfer like it did before.
i have been searching and i found that h-techs spring rates are as follows
Spring Rates (lbs/in): F(168/3), R(101/1.5)
is that saying that the spring rates for the front are really 56 lbs in front and 67.33333 lbs in the rear???
Aleks wrote:The numbers that have been posted for the stock spring rates seem to be way off. I don't think they are that high. I would guess that the rates of the factory Z24 springs are somwhere around the rates of the Apex springs.
I got these replies years ago from various companies.....
Reply From Apex:
The spring rate on the front is 152# in front and 115# in rear. Let us
know if we can help any more,
Apex Sales
Reply from Eibach (Pro-Kit):
-Is this application a progressive or linear rate spring? PROGRESSIVE
>
> -What is the spring rate (front and rear) for this application?
THE SPRING RATE VARIES FROM 154-200 IN THE F
TO 69-151 IN THE R
Reply From Eibach (Sportlines):
The front Sportline spring is progressive with a 1st rate of 122lb/in
and a 2nd rate of 225.47lb/in.
The rear Sportline spring is also progressive with a 1st rate of
58lb/in and a 2nd rate of169.73lb/in.
what does it mean when you say (about the sportlines) the 1st rate and the second rate, i dont understand that
help!
05cavalier07 wrote:i have been searching and i found that h-techs spring rates are as follows
Spring Rates (lbs/in): F(168/3), R(101/1.5)
is that saying that the spring rates for the front are really 56 lbs in front and 67.33333 lbs in the rear???
According to the tein website it is 170f and 110r
http://www.tein.com/ti/g90.html
jWagg there are two numbers are because it is a progressive rate spring, softer initially than stiffening up as the spring is compressed
Those Eibach numbers are about 25% and 50% compression by distance.
Since when are Sportlines progressive?
Ok this is the info I got.
H&R tells me that their can not provide spring rates info, but that their Sport Springs for J-Bodies are 25%-30% stiffer than stock ones. Do you know the spring rate of stock springs? Or anyone can measure the stock springs? wire width? number of coils? and spring long? I have an spreadsheet that can calc it.
And this is the answer from Koni:
Elio,
The Koni Reds have a large enough range that they will have no problems
working with the H&R Sport springs. These were originally developed to
work with a Pro-kit setup so you may only need to turn the shock up a
half a turn if you're looking for a slightly more aggressive setup.
The spring rates for the Sport springs won't be much firmer than stock
(usually 20-30% firmer). I wouldn't be too concerned with the
adjustment range until you start looking at going with a coilover system
(i.e. Ground Control). If you have any questions, please let me know.
Thanks.
Gordon
Any other info will be great.
Thanks,
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Ahhhh.....the world famous Gordon from Koni. That man is a walking spec sheet for all Koni products, as well as just about every other aftermarket spring/shock/strut out there. Hes that good. He helped me and juicedz4 when we were building our setups.
It really upsets me when companies won't put info out to the consumer. Do you know why they wouldn't give it? I don't think I would ever consider buying their products now because either 1- they just don't know what the rate is (that really scares me) or 2- they refuse to give it out because they're afraid of someone else marketing a spring with the same rate (I've got new for ya H&R, someone already has!). Saying a spring is XX% more or less than another spring is like saying "This engine has XX% more HP than that one" Unless you've run each individual spring on a spring dyno, how would you ever know what the actual rate is? Even aftermarket springs have different rates than advertised.
///end rant
I will try to measure my stock springs during the weekend to know the spring rate. I will post it when I have the info. But if anyone have the info before that would be great and I can calculate it.
You can check out this links,
http://www.miracerros.com/mustang/springs_calcs.htm
http://www.pontiacracing.net/js_coil_spring_rate.htm
I think that will exist many others but many of them point aprox. to the same info.
Will be great if people can take this measures to make some kind of table. This will help people to choose the best appl for their needs. Also selecting the right shocks or shocks adjustment will be really easier.
I remember the advice of two guys here when I begin modding my car, one is Event that will be still around here and other guy was Memnoch that had a great info a road racing and suspension setup for our cars.
Personally the difference between a great modded car and a ricer one is not money, knowledge makes a great difference. Then people help me to recolect go info about this for all of us.
Thanks in advance for your help.
Regards,
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so our stock spring rates might be as high as 200/175, I always thought they were a lot lower because lowering springs are lower than that.
Hi friends. I don't had time to measure my stock springs, during this weekend. Work and studies need too much time. Can anyone help me and send this measures?
Thanks,
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Hi friends, finally I got the time to measure my stock springs.
First I my calculation is based in a common formula to calculate coil spring rate:
k = Spring Stiffness (lbs/in) = (Wd4 x G)/(8 x Cd3 x Na), where:
Wd = Wire Diameter (in),
G = Torsional Modulus for Steel, constant =11,250,000,
Cd = Mean coil diameter, measure from the center of a coil to the center of another coil (in). That is the outer diameter of spring (in) minus the wire diameter (in).
Na = Number of active coils. Count total number of coils; subtract a coil for each coil that touches, these are dead coils. Ground flat ends are a dead coil. Start count with cut-off end facing you directly above would be one and so on. Not all coil springs are even coiled. You can have 1/4, 3/8, 1/2, 5/8, 3/4 or 1/8 of a coil (Example 10 1/8 coils).
Checkout this spreadsheets and links for more info.
http://therangerstation.com/tech_library/coilspringrate.htm
http://www.rahul.net/dennisp/suspension/demos/index.html
http://www.bluecoilspring.com/rate2.htm
http://www.guzzitech.com/SpringDesigner-talbot.html
The front springs have these dimensions:
Wd = 14mm (0.551in)
Cd = 150mm – 14mm = 136mm(5.354in)
Na = 6 + 3/8 = 6.375 – 2 dead coils = 4.375 more or less.
L = 344mm(13.543in), this is the free length of the spring.
Here are two pics of the front springs from different sides:
A pic from the upper part of it, where upper shock spring seat is located:
And the lower side:
Now a view of the rear ones:
Rear’s up:
And rear’s down:
The rear springs have these dimensions:
Wd = 11mm (0.433in)
Cd = 127mm – 11mm = 116mm(4.567in)
Na = 7 – 2 dead coils = 5,
L = 357mm(14.055in), this is the free length of the spring.
Then, all this info indicates that the stock springs have approximately the following spring rates, F (200 lbs/in) and R (105 lbs/in). Inclusive as you can see in the pics both OEM springs, for the front and rear, are linear, be careful when you compare it with progressive springs like Eibach and others.
Well, that is the info that I can obtain. As usual, I am open to your comments, corrections and ideas. And please forgive for the great delay finding the info, I mean measuring the springs.
Thanks and regards,
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wow, i thought the stockers would be a lot lower than that. I know tein advertises their springs as softer than that. it gives people something to think about when looking for aftermarket springs
Friend be careful. I try to do my calculations as precise as I can and but remember that I am not an expert about this topic. I am only an using commom sense. Inclusive take in account that these are the OEM springs of my car here in Venezuela, that I suppose that should be equal to the ones used in USA.
In the calc exist one or two things that can change vastly the things.
One is the right number of active coils for both springs, front and rears.
For the rear is quite easy because not only the spring is linear, it is simetric too. I mean every seat coil ends aprox. at the same location or distance. Then both seat coils are supposely considered dead coils and doesn't count for the active coils.
For the front, is more tricky, because although the coil spring is linear it is not simetric and with different seat sizes. That is the reason that my total count of turns for the front coil spring is 6.375 minus the two seat coils. In fact I have some doubts about this for the up seat coil. Anyway my total account of active coils for the front spring is 4.375 and this number can change the spring rate greatly.
The fact is that using a tip from DSP Suspension Design (active coils count from the demo web page pic and the info from Blue Coils, checkout links in my previous post), stock spring rates should be something like F(165) and R(95) that appears to be more real or in concordance with many aftermarket number posted here, like Eibach, Teins and others . People what do you think about this? Is an stupid issue but heavily change the things, then how many active coils do you see?
And other thing is that many aftermarket springs are progressive to retain some comfort. The these springs not have an unique rate is have a band that make it like OEMs intially and much harder when are compressed.
Thanks,
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Well friends after a little more research and comparison, seems to me that the right numbers for Cavalier/Sunfire Coupe with LD9 engine coil spring rates are
F(160lbs/in) and R(100lbs/in). People please I will like to hear some comments about this.
Thanks,
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why do you keep saying friends. Haha, i get the feeling your not fluent in english.
not baggin ya, i just thought it was cool
I know that my english is not perfect, sorry about that. But I am sure that you and people here, can understand my ideas. Quality info is like gold only if you know how use it.
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I don't have all the formulas in front of me, but it all looks to be pretty close.
Eliot, good job. Glad to see someone doing some real research and getting some good empirical data.
I'd like to see that chart of spring rates and dampenig rates, both rebound and compression. Unfortunitely the way each company calculates their dampening rates differs from one another. This will make it difficult to compare which strut would work best with which spring.
sorry to bring this back from the dead, but I got the spring rates off of the d-spec springs and shocks setup from tokico today. The tech said it was 180 front and 160 rear.
Ok no problem