[WallaceK]

Originally Posted by FaRKle!

Picking Springs
The last piece of the puzzle was choosing which spring to use. Both the BC Racing and Solowerks perches can use 60mm ID springs, although you'll probably need to remove the plastic perch on the BC unit. With the perch you can use 2.5" (63.5mm) ID springs. 65mm ID springs also probably fit fine, and you can choose to use a 60mm to 65mm adapter if you like.

To pick my spring I looked through Hyperco, Eibach, and Swift's catalogs. For my particular application I'm targeting a rear ride freq around 1.8Hz, so a 900lb/in spring is what I was after. When looking through the catalogs and searching the PNs for the spring rates I wanted I was surprised at how cheap standard coilover springs are. I saw them ranging from $50 to about $80 each, and the ones I wanted (Hyperco 2.5" ID, 900lbs/in, 10" long), ended up only being $57 each shipped.

A 9" coilover spring is probably optimal for having the most adjustment range, however 8" and 10" springs are far more common. If you decide to go with a spring rate as high/higher than mine (or you want to drop your rear height really low), you'll probably want an 8" spring instead. If you're keeping things around OE rates or up to M3/4 (~650lbs/in) then a 10" spring will be fine. One thing that's important to note is that you want it so that when the camber arm is up and bolted to the rear knuckle the spring has some load on it so it can't pop out. This is a concern if you go with too short of a spring, and is why helper springs and couplers exist.

Pardon my ignorance about springs, but I found your thread pretty interesting. Do you think a dual rate spring setup could work too?

Since your tutorial caught my attention I went through hyperco catalog and I came across those types of springs. I searched a bit and noticed that is more often used in offroad applications, but I tought that those 12B0230/700 UHT could work, since I've seen an article talking about dual rate springs for mustangs (https://www.steeda.com/mustang-progr...linear-springs, they even sell kits).

Anyway, sorry if I'm saying too much bs, I'm trying to understand about this stuff and plan the best route for my car. Also, thanks for making and sharing this tutorial, it is really cool and useful.

[FaRKle!]

Originally Posted by WallaceK

Pardon my ignorance about springs, but I found your thread pretty interesting. Do you think a dual rate spring setup could work too?

Since your tutorial caught my attention I went through hyperco catalog and I came across those types of springs. I searched a bit and noticed that is more often used in offroad applications, but I tought that those 12B0230/700 UHT could work, since I've seen an article talking about dual rate springs for mustangs (https://www.steeda.com/mustang-progr...linear-springs, they even sell kits).

Anyway, sorry if I'm saying too much bs, I'm trying to understand about this stuff and plan the best route for my car. Also, thanks for making and sharing this tutorial, it is really cool and useful.

There's no reason you can't put a dual rate spring in there if it fits. I don't personally care for them because the low rate will typically take you out of flat ride, but I suppose you could try having an extra stiff second rate too. As for the 12B0230/700, I think the low rate is too low (it's like 80lbs/in effective at the wheel). A really low rate is only good for acting as a helper spring/spacer.

[papasito2004]

Beautiful writeup and video, thx !!!

[JBF30]

Originally Posted by FaRKle!

For OE-style springs and perches you can use spacers/shims placed in/on top of the spring cup as I had in the pic below. I used 0.1" thick kydex to make them. In the pic below I have three shims in the cup (which is why the rubber looks like it's sticking out of the cup some) and two on top of the cup.


If you need a set I can make some fairly cheaply.

I’d be interested in some shims if you’re still willing to make a set. I’m trying to get the right rear sag a little less obvious with my eibach pro kit.

Thanks!

[smarz]

Originally Posted by FaRKle!

For OE-style springs and perches you can use spacers/shims placed in/on top of the spring cup as I had in the pic below. I used 0.1" thick kydex to make them. In the pic below I have three shims in the cup (which is why the rubber looks like it's sticking out of the cup some) and two on top of the cup.


If you need a set I can make some fairly cheaply.

How far did it raise your ride height?

I'm looking into similar option but may go with the DIY HAS using my eibach pro kit if this doesn't raise the car that much.