4 link rear with coil overs?

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A408Cuda

A408Cuda

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Anybody running 4 link rear with coilovers? I'm curious what spring rate guys are running my coils are mounted at 18 degrees with 200lb springs and I think they are to light. I was thinking about going to 250lb springs but was hoping somebody has some experience and would chime in. Shocks and springs are QA1 adjustable with 2.5" x 10" springs on a 64 Barracuda.
 
I'm running 175 lb / 12" springs on the back of a Duster. can't remember the angle, but I mimicked the factory pulling the top mount inward. Of course, the more angle, the higher spring rate you need.
 
Ya my tops are in and lowers are as far to the outside as i could get them, if 175 is good for the duster I would think I should be fine with 200's maybe I need to crank them up the shocks a little farther their about half way now.
 
I'm running a triagulated 4 bar, upper mounts about 20 deg inboard. 12" eye to eye at ride height, 4" stroke dbl adjustable vikings with 250# 10" coils. The coils are adjusted to have 1 3/4"" rise and 2 " compression. My car is a little lighter than stock so it's a little stiff at road settings (6 clicks off 0 compression and 7 clicks from 0 on rebound),but great driveabilty. Track day is 0 compression (soft),it bites hard and transfers well. The trick I've found "street manners" wise is to adjust the spring to have centered stroke and have enough stiffness not to bottom the shock piston or coil bind.Stance affects spring rates as well. When I dealt with Viking they told me to set my desired ride height first, pick a shock for that ride height (centered stroke)and then springs to follow. I followed the same advice for the HDK setup and only had to shelf 1 set of rear springs (#300) and one set of front progressives(225/475)
 
I haven't even run the car yet just started messing with ride height and It feels like I'm running the springs to compressed to get the height I want, I don't even have the rear glass in yet, probably another 80lbs, the car is half full of fuel and all other equipment is pretty much in. Mine is also a triangulated 4 link. I do have speakers a amp and the battery back their, after describing your setup I'm thinking I might need the 250's after all. Below is what I currently have. with the #200 springs.

QA1 Adjustable 12 Inch Coil-Over Shock Kit
Universal Fit, 12" Mounted Length, Aluminum Shock Body Material
Mounted Length:
12"
Shock Body Material:
Aluminum
Compressed Length:
10.125"
Extended Length:
14"
Compressed Length Range:
10.00" to 10.99"
Extended Length Range:
14.00" to 14.99"
Sold in Quantity:
Kit
 
A408Cuda said:
I haven't even run the car yet just started messing with ride height and It feels like I'm running the springs to compressed to get the height I want, I don't even have the rear glass in yet, probably another 80lbs, the car is half full of fuel and all other equipment is pretty much in. Mine is also a triangulated 4 link. I do have speakers a amp and the battery back their, after describing your setup I'm thinking I might need the 250's after all. Below is what I currently have. with the #200 springs.

QA1 Adjustable 12 Inch Coil-Over Shock Kit
Universal Fit, 12" Mounted Length, Aluminum Shock Body Material
Mounted Length:
12"
Shock Body Material:
Aluminum
Compressed Length:
10.125"
Extended Length:
14"
Compressed Length Range:
10.00" to 10.99"
Extended Length Range:
14.00" to 14.99"
Sold in Quantity:
Kit
Click to expand...

Reading this w/ interest. I just changed my front coil over shocks, and installed 250# springs . I had previously ran 350# springs, after changing out the 500# springs that came on m set up. It was so stiff w/ the 500 springs it rode like a go cart. The 350`s were better, but could not get any front end lift at all.
Have been wondering what guys are using in the rear ----------
If a shock will extend to 14" shouldn`t that shock be called a 14" shock instead of a 12" shock ? Aldun American goes that way . ????
 
I started with the 200's at QA1 recommendation, I think its would have been fine with everything stock, but its not, I really don't know how a guy chooses what to start with, maybe if I had a scale that could weigh the weight on each tire?? Hell I don't know??
Im QA1 uppers and lowers up front with PST 1.03 bars
 
Shocks are ordered at desired ride height measured eye to eye. A centered 14" extended 4" stroke shock allows +/- 2" from center of stroke (installed). You can adjust the spring tension (ride height) and it will affect the useable stroke.
 
I get the shock length, its the spring rate that's off. I set my ride height where I want it puts my shock in the correct position but my spring nut, used to adjust ride height is way up on the shock now, close to the top. I don't think that's correct, I would think it should be closer to the bottom of the shock with the proper spring rate. I other words I'm compressing the spring to almost max adjustment to get the desired ride height.
 
you don't think 250's or maybe 220's? I have 200's now.. That's where I'm struggling, how to determine spring rate needed without just buying different rates and trying them. There must be a more technical way to determine ideal spring rate.
 
my bad 250's. As far as not experimenting, you would need scales and a knowledgeable spring/chassis set up rep.
 
A408Cuda said:
Anybody running 4 link rear with coilovers? I'm curious what spring rate guys are running my coils are mounted at 18 degrees with 200lb springs and I think they are to light. I was thinking about going to 250lb springs but was hoping somebody has some experience and would chime in. Shocks and springs are QA1 adjustable with 2.5" x 10" springs on a 64 Barracuda.
Click to expand...
To get you adequately close you really need a set of 4 corner scales. But what front rate are you running? Coil or T-Bars? Also, vehicle weight? Ride Tech has a nice calculator if you know your front rates and weights. My Gerst kit came with 10 inch springs for the rears with #275s on them.
 
A408Cuda said:
you don't think 250's or maybe 220's? I have 200's now.. That's where I'm struggling, how to determine spring rate needed without just buying different rates and trying them. There must be a more technical way to determine ideal spring rate.
Click to expand...
It depends on the front set up heavily. To get 4 corner coil overs set up right without experimenting, you need 4 corner scales. However, you can get it in the ball park with calculating what you will need based on your front specs and your rear specs. You'll need to know your front rate, your front and rear unspring weight, vehicle overall weight and your front/rear weight balance ratio.
 
dukeboy_318 said:
It depends on the front set up heavily. To get 4 corner coil overs set up right without experimenting, you need 4 corner scales. However, you can get it in the ball park with calculating what you will need based on your front specs and your rear specs. You'll need to know your front rate, your front and rear unspring weight, vehicle overall weight and your front/rear weight balance ratio.
Click to expand...


Front is still T bars PST 1.03's with all QA1 components, control arms strut bars. 1 1/8" sway bar.
I dont have the scales needed to get the weights so i guess im going to just have to try the 250's next.
 
A408Cuda said:
Front is still T bars PST 1.03's with all QA1 components, control arms strut bars. 1 1/8" sway bar.
I dont have the scales needed to get the weights so i guess im going to just have to try the 250's next.
Click to expand...
Or... go to SCCA tech event or an auto cross, often times there’s guys there with 4 corner scales that will let you weigh out for a small fee. We did that with my cousins Camaro more than once. Usually 20-50 bucks depending on the person there.
 
A408Cuda said:
Front is still T bars PST 1.03's with all QA1 components, control arms strut bars. 1 1/8" sway bar.
I dont have the scales needed to get the weights so i guess im going to just have to try the 250's next.
Click to expand...
And one thing I should ask, why do you think they’re too light?
 
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