Quote:
Originally Posted by Orb
The actual spring rate is not important regarding dampening as we only care what the wheel will see. The important thing regarding the damper is the suspension frequency and the motion ratio of the damper. The motion ratio of damper is .81^2. It is squared since we have force and velocity but that not 100% correct when we dive into this but good enough for now.
The rear grip on corner exit will be governed much more by the roll bar stiffness than the spring until you get straighten out. If you are running R compound tire you will not optimize grip until you have at least 2 Hz rear suspension frequency (ideally you want 2.2 Hz). If you are running street tires then 800 lb/in in the rear is good but the 2.2 Hz frequency in the front suspension is too high. The point is softer suspension is only good if your maximizing your friction from the tires which is function of suspension frequency. The key thing is when you go stiffer then binding; friction and a non linear spring rate become the problem which results in poor grip and harshness and is compounded by the high rear motion ratio of the rear suspension. Many tuner will not deal with these issue which is a big big mistake….you have to, and do it well, and it is not easy.
If you talk with Pete at TC he has a good understanding of the motion ratio and what the damper can work with which is up to 1200 lb/in rear spring.
A 400 lb/in front spring is about softest you want to go for tracking or pitch is not well controlled. A 450 lb/in the front and 900 lb/in rear will give you the best of both worlds if your running R compound tires and street tire for your daily drive and give you similar balance.
The springs you can get from TC are much better than H&R ect but they are not really the best or most linear you can get. Swift springs are more less the only thing you should be using if you want a very smooth ride. From my own tuning experience this was the most important thing bar none. You can talk with Harold at HP Autowerks as well about this as he has gone through this comparison.
Orb
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Thanks for all the input from everyone here. It's a LOT more than I thought I would get.
Orb, would you recommend 450 lbs front and 900 lbs rear for most street use and a 2-4 track events a year on street tires?
And in regards to the Swift springs, where would you get those and could you use them with a TDK system? Honestly, I'm sure I'm not at a level I would notice.