I'm back to talk about spring rates.
 

Ok so this is the week I'm finally ordering my coil overs. I decided on FA 500 TRUE REARS for many reasons. and ill be doing all the spl arms and **** the following week. but the only thing I am having trouble figuring out are the rear spring rates. I am switching to TRUE REAR and I daily drive my car in the summer and it will see the occasional track event and lots of twisty roads. so what are some good rear rates to choose for what I just mentioned. everything I see on the internet are people just straight tracking their car and they go with **** stiff springs which I don't really want... yes I know this type of stuff has been discussed alot before I'm just lazy and would appreciate all the help I can get! thanks guys!:happydance:

Just throwing this out there, I would avoid admitting that you are lazy. Some folks on this forum may not take kindly to that....BUT, here are a a couple links to read and get you started (google search). I wouldn't recommend skimming through the first as you are going from a divorced set up (OEM configuration), to a "True Rear" set up. There are a few more things to take into consideration as you are shifting the load of the suspension.

Suspension Design – RR Racing Information (a lot of good info)

https://www.m3post.com/forums/showthread.php?t=1479726 (M3 I know, but same general scenario)

Best of luck!

Yeah it has been discussed a lot, and Fortune Auto aren't reliable as far as suggested spring rates, when you are converting from divorced to true type. It all depends on how stiff you want and if you daily drive the car, my car is acceptable with 21kg and 7kg, I would guess for better dd you need to go down to like 14 kg front 5 kg rear, or maybe 6 kg rear and if the car oversteers, it could be dialed back by getting thick front swaybar.

The standard 12k front is enough on the rear you need to consider wheel rate as part of your consideration from moving from a divorced setup. You should in that 5 to 7k zone.

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Yea its actually 11k and 8k but i think ill do 11k and 6k

11k in the front seems rather low for a car that will see a little track duty. This notion that stiff springs kills ride quality is just because people have dampers that aren't properly valved for the spring rate. You'd be surprised how stiff you can go and still be comfortable when you have well valved dampers.

I wouldn’t worry about 12k front, I’ve been on 12/11 (OEM style) and it’s been fine on street, in fact if anything the rear is a bit firmer feeling than front (maybe wanted 10 but wasn’t an option). Odd that fortune would recommend you 11/8 true type as they used to spec 10/8 OEM type when I was looking at them. Which is one of the reasons I didn’t go that route since I did want to do some track and it just didn’t make sense to me that I would jump up two rates in front and keep the rear same as oem spec (8/8). You definitely do not use the same rates true type as you would oem type so I would be questioning that recommendation, seems most true with street setup are somewhere around a 12-13 front with a 6-7 rear.

this x10000

stiff springs dont kill ride quality as much as bad dampers

14k/10k here on Aragostas and the ride is just as good as stock

I was curious about the Aragostas before, didn’t realize you had them and live in Sacramento. Maybe I’ll have to try to get a ride sometime in summer on my way to Tahoe if your up for it.