TRACK OG's ONLY!!

synolimit

Call an engineer at Stance, Fortune Auto etc. Spring rate calculators can be used to determine this as every single component of a system adds to it, aero, type of tire (slick, DOT etc) etc. they'll give you the best advice.

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13 370z-

Jhill

Not going to go through the list as everyone has already basically explained the same thing.

As far as spring rates go then there truly isn't one "perfect" rate. Even within all the coilover they use different rates, suspension is subjective and what is right for you may be trash for someone else. When it really comes down to fractions of second they switch spring rates per course as well, a rougher course runs a softer spring and vice versa. I imagine weather plays a role too, can't have stiff as a rock suspension on a wet surface or all you'll do is slide.

If your looking for a good compromise suspension any of the fortune, bc, stance or powertrix (what I chose) will work good and all can reach relatively the same rates (since general rule is + / - 2k without a revalve. Although I guess if you start a little firmer like stance/powertrix 12/10 then you can drop to bc 10/8 or jump up to 14/12 whereas bc you can drop to 8/6 but that's actually softer in rear than oem and same as oem in front and can only reach stance/powertrix starting rates of 12/10.

And as mentioned above you can not compare rates one car to another as the leverage ratios are not the same for example your genesis may use a inboard spring with a very long control arm in the rear with a McPherson strut front (I don't know the genesis so just making it up). Now take a guess where most of the weight of the car will be up front with the engine or in the back with just a diff? Hopefully you guess up front, so then how is it possible for the front to a 4K lighter spring and still support the front? Leverage rate.