Rear 1st gen coilover chatter

[Chris]

I didn't see this mentioned anywhere after searching a bit. I was wondering how you 1st gen people alleviate the "coil chatter" when the coils unload when going around a corner, hitting a pothole, etc? With it being spring after a harsh winter, the roads around where I live absolutely suck. Frost heaves, cracks, potholes, washboard dirt roads, etc... The coil chatter is driving me up the freaking wall.

 

I do have rubber isolators but that doesn't seem to help at all. I was considering adding some 25lb coils so the main coils aren't able to fully unload (like this), but that's probably going to give my car more of a lift in the rear than I want, although I guess I could get shorter or lower-rate coils.

[CSI_MuNkY]

What coil over kits do you have?

[mra32]

Helper springs like you mentioned are one commonly used solution. Ive never seen them used on w-bodies and i think you would need a coupling spacer between the springs as well which would be custom.

 

I also think that a large rear sway bar with stiff bushings might help too. what rear sway bar are you running?

[Chris]

Custom-built coilovers, no rear sway bar, and I kept the monoleaf*

 

*(which is why the coils unload so easily, I kept the monoleaf because I tow with the car, and didn't want to put like 500lb coils in the rear - I don't think my wheelwells would have enjoyed that)

[mra32]

I guess these are the couplers:

 

http://www.amazon.com/Genesis-2-5-Helper-Spring-Guide/dp/B000W7IF44

 

and these are the springs:

http://www.amazon.com/HYP-HS250-Hyperco-Hypercoils-Helper-Springs/dp/B003POK27E/ref=sr_1_20?s=automotive&ie=UTF8&qid=1303764651&sr=1-20

 

so youre looking at another $140 for the helper spring route. You may be able to find them cheaper somewhere, but I never did when I was looking

[Chris]

Ahhh yes, those look like a good solution.

[xtremerevolution]

Ahhh yes, those look like a good solution.

 

Only for that price, you can almost get a set of very light rear 10" coilovers instead, sleeves, nuts, and springs included.

[CSI_MuNkY]

Take out the monoleaf, that's probably most of your problem right there... Mine never unloaded completely while driving, I literally had to lift the back of the car off the ground to get them to unload.

 

Once that is out of the way put a 7/8" addco sway bar in there. www.p-s-t.com used to sell them with poly bushings, however I no longer see it listed.

 

Also, what are you using for an upper mount?

Edited April 25, 2011 by CSI_MuNkY

[19Cutlass94]

Energy suspension sells all the bushings. Thats where I got mine. But Ive never had that problem.

[Chris]

Only for that price, you can almost get a set of very light rear 10" coilovers instead, sleeves, nuts, and springs included.

Yeah, that price is a bit much, I'll look around before I decide against anything.

 

Also, what are you using for an upper mount?

I had a friend machine some for me, they were prototypes that we were going to mass-produce, but couldn't find enough interest.

 

[CSI_MuNkY]

I've seen those before, there used to be a company making them like that... My how coil overs have come along...

This is the upper mount I am using, completely replaces the stock mount

 

 

With this mount I use a 12" spring, never had any issues.

 

What spring rate are you using?

 

 

If I were in your shoes, I would start by removing the leaf spring and getting an addco bar

My kit from PST (along with a whole front end kit I also got from PST)

[Chris]

Again, I tow with the car and don't want to put that amount of stress (the full weight of the car, then the weight of the trailer) on the wheelwells, I don't see a need to remove the monoleaf because there's nothing wrong with it. Although a large amount of stress is on the wheelwells when towing with the coilover "helpers" it's not nearly the same amount that would be there if I removed the monoleaf. I'm not trying to lower the car, in fact I'm doing the exact opposite. My setup works perfect for it's intended use, minus the annoying chatter. Besides, with 19 years of harsh salt-filled winters, I'm not even going to bother attempting the removal of the monoleaf.

[mra32]

Ohhhh i misunderstood the problem. I imagine the chatter you hear is alot more compared to people who are on coilover only because you still have the monoleaf on there. Hit a small bump and it would be very easy for the monoleaf to lift the suspension out of the range of travel of those coil springs. No matter what rate springs you have, the monoleaf will lift the car off the springs if the spring isnt long enough.

 

First step I would take is to find spings long enough. Measure from where the spring sits on the top mount to where it sits on the bottom mount at full droop. So jack it up and take the back wheels off and measure. I'd imagine if you had the lower perch somewhere close to the bottom of the threaded sleeve, that would be ideal if you could find a spring that long since that way you could jack them up for moar spring powar

 

I only know of 14" springs, so if you screwed the lower perch up to the top and was able to get that distance between the two just under the length of spring you can find, I'd say you would be good. I'm sure you can figure out what spring rate to go with.

 

 

If you cant find springs long enough, I'm sure your machinist friend can whip up a spacer that goes between either the top or bottom perch and the spring and that should preload the spring at all times to make sure the spring does not come unseated.

Edited April 26, 2011 by mra32

[mra32]

http://shop.a1racing.com/all56116.aspx

 

this might work. I dont know what the dimensions are though

[CSI_MuNkY]

What are your springs rated at?

 

Another option would be to take the majority of the work with the coil springs and allow the leaf to be the helper. You would need to figure out what spring rate to go with though. My guess would be a 300lb/in

[Chris]

Ohhhh i misunderstood the problem. I imagine the chatter you hear is alot more compared to people who are on coilover only because you still have the monoleaf on there. Hit a small bump and it would be very easy for the monoleaf to lift the suspension out of the range of travel

 

First step I would take is to find spings long enough. Measure from where the spring sits on the top mount to where it sits on the bottom mount at full droop. So jack it up and take the back wheels off and measure. I'd imagine if you had the lower perch somewhere close to the bottom of the threaded sleeve, that would be ideal if you could find a spring that long since that way you could jack them up for moar spring powar

 

I only know of 14" springs, so if you screwed the lower perch up to the top and was able to get that distance between the two just under the length of spring you can find, I'd say you would be good. I'm sure you can figure out what spring rate to go with.

 

 

If you cant find springs long enough, I'm sure your machinist friend can whip up a spacer that goes between either the top or bottom perch and the spring and that should preload the spring at all times to make sure the spring does not come unseated.

 

Exactly. I had the coilovers adjusted so the springs were under a constant preload, but it gave the car one hell of a rake, so I adjusted them down where the right height is perfect. With the springs adjusted the way they are now, there's enough for them to unload and chatter easily, but under full droop there's only like an inch between the top of the coils and the mount.

 

I currently have 14" 150lb springs installed, and other than the chatter they work perfect. I have considered replacing the 150's with some 14" dual-rate springs, like 75/200 or something along those lines and then adjusting the preload and height from there.

[mra32]

I think with your requirements/desires, the stinkbug stance might be somewhat unavoidable. The progressive coil springs do sound like a fine idea, but you might be buying a couple springs to get it where you want it. Those helper springs might be the ticket if you end up having to buy more than 1 more pair of springs to test and get the look and functionality you want, though.

 

Have you found any progressive 14" springs?

 

Maybe just a lower spring rate?

Edited April 26, 2011 by mra32

[CSI_MuNkY]

There is a list of the different monoleaf rates for each RPO code on here somewhere. I would try to match what you have stock with the springs.

[Chris]

What are your springs rated at?

 

Another option would be to take the majority of the work with the coil springs and allow the leaf to be the helper. You would need to figure out what spring rate to go with though. My guess would be a 300lb/in

 

I have 14" 150lb springs in the coilover assembly. I think 300 would be a good number if I removed the monoleaf, but it would be way too stiff with the monoleaf still in the car.

 

 

This is how it sat with the coils preloaded:

 

 

 

This is how it sits with the ride height adjusted so there's no preload:

 

 

 

 

 

Now if I lifted the front to match, and get some good mud tires....

[Chris]

I think with your requirements/desires, the stinkbug stance might be somewhat unavoidable. The progressive coil springs do sound like a fine idea, but you might be buying a couple springs to get it where you want it. Those helper springs might be the ticket if you end up having to buy more than 1 more pair of springs to test and get the look and functionality you want, though.

 

Have you found any progressive 14" springs?

 

Maybe just a lower spring rate?

 

That's what I was thinking, which is why I figured I'd bring up the question here... I did find 14" progressive coils when I originally purchased all the parts, but decided against them at the time. I use to carry a trunk full of tools, my welder, and other crap in the back so I never had this issue. Now that I'm riding with an empty trunk, it's much different.

 

There is a list of the different monoleaf rates for each RPO code on here somewhere. I would try to match what you have stock with the springs.

 

I'll do a search and see if I can find what the car came with. it's probably the lowest-rate super-base stock no options for anything RPO, because that's what this car is. I'm surprised there was even a cassette player.

[mra32]

 

 

This is how it sits with the ride height adjusted so there's no preload:

 

:lol:

 

Well it looks like you have a little bit smaller tires in the front on the first pic, right? thats certainly not helping you with the angle, but it still looks extreme. It even looks a little high in the second pic. Just curious, what are you towing?

[Chris]

It was about 1" higher in the rear, but the coils have settled in a bit and now it's level.

 

IIRC there was only a 3% difference in the front to back tires, I had the small ones on the front because I blew a tire when I hit a pothole the size of Montana. The rake wasn't exaggerated too much by the smaller tires, because it even had a rake when the smaller ones were on the rear (and BOY did that look weird!). There was 8" of difference between the front and rear with the smaller tires on front, and about 7" with the same size tires all the way around.

 

I mainly tow my 8x8 snowmobile trailer with a pair of heavy vintage junk, but it doesn't always have snowmobiles on it. I've loaded it up with pretty much anything that could fit