Spring rate help?

Shamu · 08-13-2014, 12:52 PM

Quote:

Originally Posted by GSS138

350 completely and respectfully disagree. Disagree since the freq calcs include corner weights, The guy I am talking to is Gordon Benson from Koni that engineered the 2812 long body. I know Koni these days isn't the "cool kids" choice of dampers, but math is math. If you want email him at Gordon.benson@itt.com. Guy is awesome and will even get into the calculus of it.

Every post market "spring kit" out there tunes to something around .80-.85
because they can sell that product and not kill someone. Or at least not be sued for creating an "unsafe ride rate" as per the DOT.

that being said, I don't drive your car that you know intimately. I see what you are saying, because you know your car's frame, your sway bars, your tires, what you like, etc. better than I do, and are a much more experienced driver. But as for a baseline tuning point, and to understand how a suspension works(regardless of the car) the Front ride Freq/ rear ride Freq, tells you how the car is setup. <1 induced understeer. > 1 induced oversteer. That's not my opinion that's just physics. Doesn't tell you how to drive it fast, doesn't make you push the throttle when you know you maybe shouldn't, it's just a reference point.

Youre right that math is math. Sometimes math cant account for weight dynamics of certain cars, tires, alignment settings, etc. Way too many variables. Practical expreince outweighs math everytime in my expereince on track. I have worked with top suspension guys around world on numerous cars and while motion ratios are good benchmark they arent good at factoring what is happening with swaybars dynamic loads etc. And I have see fast setups that completely defy what experts would calculate with standard frequency formulas.

What I have seen with some regularity for full coilovers on 370Z race cars is front range of 1000 to 1200 lbs and rear of 600 to 900 lbs. These are on cars races in series such as Continental and Pirelli and on either DOT or race slicks. Full on race slicks do need signficantly more spring due to stickage factor. I usually jump 200 lbs from rates I use for DOT tires minimum.

And differnt tracks may dictate changes as well. Im planning on having a range of springs from 1000 to 1200 front and 600 to 900 rear. I just know my old DOT setup of 1000 front and 500 rear is allowing too much rollover with slicks.

GSS138 · 08-13-2014, 01:11 PM

Absolutely 100%. And like I said, these numbers sure as hell don't teach you how to drive or win anything for you.

But what they are useful for is tuning.

So if you know your car is setup with say a 1.15 ratio, and man you just need the *** end to swing around a little bit faster, you can now with no guess work select a spring that is going to help move your car towards 1.20 which should make it a little looser.

It's just a tool and a reference. And it sure as heck can't tell you what you like or prefer, it's like saying "hey it's 70 degrees outside". Some people might like it, some people might not. Some people put on a jacket, some people go swimming.

08-13-2014, 01:11 PM	#2 (permalink)
GSS138 Track Member Join Date: Mar 2013 Location: Mission Viejo, CA Posts: 769 Drives: '12 370Z 6M Sport Rep Power: 14	Absolutely 100%. And like I said, these numbers sure as hell don't teach you how to drive or win anything for you. But what they are useful for is tuning. So if you know your car is setup with say a 1.15 ratio, and man you just need the *** end to swing around a little bit faster, you can now with no guess work select a spring that is going to help move your car towards 1.20 which should make it a little looser. It's just a tool and a reference. And it sure as heck can't tell you what you like or prefer, it's like saying "hey it's 70 degrees outside". Some people might like it, some people might not. Some people put on a jacket, some people go swimming. __________________ Current Mods: Vorpal Weapon +5.

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