C3 Rear Spring Questions

I have a question about the rear springs. A lott of people want to go to coilovers. But what is so fascinating about them. Do they really have a purpose besides getting the car at equal height left and right ?

Is there something known about the cantilever system (if that is what it is called) ?

Thanks

No, everything you see aftermarket is bling stuff. Xander has them too but he broke the lid on his diff and getting a new HD diff cover shipped was almost 75% of what the coil overs would cost (well, if the 1st set of shocks actually fit, they didn't and the aldan adjustable ones raised the price by 400% ) so that's why we did that, and it fits the pro touring theme.

I have yet to see someone use that shark bite rear coil over setup or whatever the cam setup is called. It's a dud, I said so from the get go. Design wise it's all wrong, the ratios are all wrong, in the test video they had coil overs + stock shocks because the crappy ratios mean they have to use super stiff springs and super stiff shocks to retain any worthwhile wheel rate.

A 900# spring says nothing, the wheel rate, that's what's important.

From everything I can find and read, that the sole benefit of a coil over system is independant adjustability of each corner.

guru said:

From everything I can find and read, that the sole benefit of a coil over system is independant adjustability of each corner.

Click to expand...

wouldn't that be easily done simply by running the nut up/down over a longer bolt???

:idea:

Many spring rates available, plus you can change your springs by removing two bolts in just a few minutes. Plus setting corner weights.

Agree with TT on the ratio, We used the old fashioned way to find the ratio, by using the weight of sands bags to compress the rear suspension one inch. Finding out our true spring weight. finding out our ratio.

the suspension vertical stiffness or wheel rate is how much force or weight at the wheel is necessary to move the car down one inch. All about the mechanical advantage or leverage. A 475lb spring rate can become a 300lb. spring weight.

mrvette said:

guru said:

From everything I can find and read, that the sole benefit of a coil over system is independant adjustability of each corner.

Click to expand...

wouldn't that be easily done simply by running the nut up/down over a longer bolt???

:idea:

Click to expand...

I found out that turning the nut does very little to the ride height on one side. Turning the nut on one side tends to bring the entire rear higher.

I understand the ratio effect on the spring pressure.

So basically you all agree that there is little extra in coilovers besides independant adjustability.

Belgian1979vette said:

mrvette said:

guru said:

From everything I can find and read, that the sole benefit of a coil over system is independant adjustability of each corner.

Click to expand...

wouldn't that be easily done simply by running the nut up/down over a longer bolt???

:idea:

Click to expand...

I found out that turning the nut does very little to the ride height on one side. Turning the nut on one side tends to bring the entire rear higher.

I understand the ratio effect on the spring pressure.

So basically you all agree that there is little extra in coilovers besides independant adjustability.

Click to expand...

HUH?? just turning ONE nut would affect the other side also??

gotta ask....why???

phreaking suspension mods, I only know from bushings and sway bars getting into suspension engineering is something I don't understand very good....
I can understand the basics...such as SA/LA, etc caster/camber/toe

but the above make NO sense to me....

:shocking::gurney:

mrvette said:

Belgian1979vette said:

mrvette said:

guru said:

From everything I can find and read, that the sole benefit of a coil over system is independant adjustability of each corner.

Click to expand...

wouldn't that be easily done simply by running the nut up/down over a longer bolt???

:idea:

Click to expand...

I found out that turning the nut does very little to the ride height on one side. Turning the nut on one side tends to bring the entire rear higher.

I understand the ratio effect on the spring pressure.

So basically you all agree that there is little extra in coilovers besides independant adjustability.

Click to expand...

HUH?? just turning ONE nut would affect the other side also??

gotta ask....why???

phreaking suspension mods, I only know from bushings and sway bars getting into suspension engineering is something I don't understand very good....
I can understand the basics...such as SA/LA, etc caster/camber/toe

but the above make NO sense to me....

:shocking::gurney:

Click to expand...

Well Gene, I guess it has something to do with the fact that the spring is connected to the diff in the middle and pushes down on the wheels. If you turn the nut, you make the middle come up, not the trailing arms. But I might be wrong, but anyway, it didn't make much difference for me.

COIL OVER vs Fiberglass MONO LEAF Spring -- REAR SUSPENSION

This thread hasn't been active for a bit - but rather than start a new one -- I did a lot of looking, and think my questions fit here, so:



and,


I know it seems logical, but if you compress the coil-over using adjust nuts, or spacers they'll get stiffer (linear right)? SO, if you got 300 pound coils, then cranked them an inch they'd be...Stiffer? And/also change the ride height on that corner too.

Seems like thats reasonable.. but I never quite got springs. Though I am still in the design and build phase, I want to sort the design and start welding while the time presents.

THANKS and,
Cheers - Jim

Turning up the adjuster raises the car and makes the coil stiffer, as the rate stays the same but the load does not. It a 300lbs spring takes 300lbs to compress 1 inch and 600 for 2....so, if you had turned up your adjuster an inch...well you get the idea

Spring rate depends on what you want for a ride and also the location of the spring vs. wheel rate. Not all are equal.

Doesn't someone else make a coilover system besides Speeddirect?

Yes, Van Steel, Jim Meyer racing. Van Steel has a nice rear setup, the front arm is a little iffy IMO with the way the coil over mounts off a bar intruducing a lever (torque) there. The Meyer arms have a full plate welded there, personally I feel their front arms are better.

Meyer:


Van Steel:

OK, now I gotta ask, why go to front coil overs? Is it just ease of changing ride height and adjustability? Does going to front coil overs improve handling or ride in any way? I've already been convinced to keep my plastic rear spring, a $1000 saving, and I just saved $1300 on rack and pinion steering by simply adjusting my steering gear. Maybe I can save another grand by keeping my standard shock and coil spring setup.
Bee Jay

Bee Jay said:

OK, now I gotta ask, why go to front coil overs? Is it just ease of changing ride height and adjustability? Does going to front coil overs improve handling or ride in any way? I've already been convinced to keep my plastic rear spring, a $1000 saving, and I just saved $1300 on rack and pinion steering by simply adjusting my steering gear. Maybe I can save another grand by keeping my standard shock and coil spring setup.
Bee Jay

Click to expand...

Well, just a couple opinions of mine. First, the downside: Cost.
The upsides are ease of adjustability. It's pretty darn easy to change the springs, and a wider selection of rates are available. With the stock system, all I've ever seen was 280, 460, and 550 pound rates. Corner weighting is possible with coilovers, whereas the standard setup doesn't really allow that very efficiently.
The major difference I see with coilovers is the location of the shock. It should be possible to put the coilover (with custom lower A-arms) closer to the wheel. This allows more shock travel for the same amount of wheel travel. The stock setup has the spring and shock at about the center of the lower arm, while a custom setup will ideally put the coilover closer to the wheel.

Exactly that's what I did, put the shock closer to the ball joint so the wheel & shock/spring rates are more closely related improving shock and spring efficiency.

69427 said:

Bee Jay said:

OK, now I gotta ask, why go to front coil overs? Is it just ease of changing ride height and adjustability? Does going to front coil overs improve handling or ride in any way? I've already been convinced to keep my plastic rear spring, a $1000 saving, and I just saved $1300 on rack and pinion steering by simply adjusting my steering gear. Maybe I can save another grand by keeping my standard shock and coil spring setup.
Bee Jay

Click to expand...

Well, just a couple opinions of mine. First, the downside: Cost.
The upsides are ease of adjustability. It's pretty darn easy to change the springs, and a wider selection of rates are available. With the stock system, all I've ever seen was 280, 460, and 550 pound rates. Corner weighting is possible with coilovers, whereas the standard setup doesn't really allow that very efficiently.
The major difference I see with coilovers is the location of the shock. It should be possible to put the coilover (with custom lower A-arms) closer to the wheel. This allows more shock travel for the same amount of wheel travel. The stock setup has the spring and shock at about the center of the lower arm, while a custom setup will ideally put the coilover closer to the wheel.

Click to expand...

Translation please. Does it improve handling or ride quality?
Bee Jay

It improves the ability to tailor the suspension to your needs, however this is strictly from a design standpoint. Considering the implementation of these kits in C2/3s...not all that great IMO. The coil over shocks are super short, and a bitch to adjust with a wrench right up there between the arm and spring pocket. The stock upper mount is not designed to take that kind of load either.

For a proper setup you need something like this, but it involves a little cutting here and there:

Twin_Turbo said:

It improves the ability to tailor the suspension to your needs, however this is strictly from a design standpoint. Considering the implementation of these kits in C2/3s...not all that great IMO. The coil over shocks are super short, and a bitch to adjust with a wrench right up there between the arm and spring pocket. The stock upper mount is not designed to take that kind of load either.

For a proper setup you need something like this, but it involves a little cutting here and there:

Click to expand...

:shocking::waxer::bonkers::crap: BRUHAAAAAAa a 'little cutting' sure, maybe for THIS forum....:yahoo::1st: