Sure, those numbers look familiar, and it's the same process that I used to pick about 2.6 Fr and 2.3 Rr frequencies for my setup which equated to about 800 & 700 lb springs.

Josh, the best you can do is pick the frequency that you can live with, then plug in the numbers.

Now that the season is over I've been thinking about the street-ability of my setup. Now that I have run on monoball suspension points and the stock rubber bushings I prefer the bushings for every day driving, considering that we have concrete and pothole roads everywhere. So for now, I've lowered the spring rate to just above the CR, and tonight I'm putting on the stock top mounts, for comfort.

In the spring I may even race on this setup, keeping my Konis on, just for fun, if I'm around.

 

It's a decent way to choose a starting point for a build. It also gives you more knowledge about front:rear balance and how hardware changes (springs, bars, weight reduction, etc.) will affect that balance. Does these numbers mean absolutely nothing? Heck no... they're just another tuning tool.

 

I can live with as high of a frequency as it needs to be as long as it's the right one. I guess a better question would of been "what is the typical frequency range for a autocross car?"

do we know Nicks frequencies and his roll rates, and bias?

-thanks

 

I whole-heartedly agree. I play with the numbers because I enjoy explaining why things are the way they are- it allows me to hold an educated conversation. It is also part of my hobby.

Just to poke holes in the natural frequency argument, it takes 1200lb springs to run an "ideal" natural frequency on an STU E36/E46 M3. We ranged from 550lb-750lb. Whoops.

What is ideal? The stiffest you can stand without being annoying, the bias that lets you focus on the course, the height that gets through your driveway. Oh wait, that is my ideal setup.

 

The range you are asking about is in your quote, Josh. It's getting a little old reinventing the wheel for you.

 

Sorry man. I'm going to go read.

 

This Josh.

 

If you believe Dennis Grant,

http://farnorthracing.com/autocross_secrets5.html

 

I interpreted that info to be specific to FWD, so I reversed the frequencies, and also found other info to point that a higher front freq is desired in RWD cars.

 

I saw that but I didn't post it because I didn't want to start a flame war. Thats completly backwards to what some str guys are doing. Although I saw a s2k guy post that the ratio should be around 15% more on the end of the car without the drive wheels. Which would be in the range of what the str guys are using.

The set up I was thinking about using is 2.61 hz front/2.27 hz rear which would be 15% towards the front. The roll rate would be a 68% front bias. I'm curious how it turns out.

I'm curious what thenicks numbers are.

I'm also trying to figure out what "65% critical" means when your talking about shock settings but that can be for another day after I get my shocks rebuilt and post shock dynos in my jrz thread.

-edit like robinson just said I at first thought he was talking about fwd cars.