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View Full Version : Suspension Leverage Ratio for Corvette C4 IRS



aosborn
04-13-2011, 07:13 PM
I am working on calculating the suspension frequency for my latest project car. It has a 1988 Corvette C4 IRS with coil-overs. I have built lower coil-over mounts essentially in the same location as the stock lower shock mount. With that mount being on the hub, would that make the leverage ratio 1-1?

Running the numbers with a 1-1 leverage ratio, my currently installed spring rate comes out to 167 cpm, and I don't believe it is anywhere near that stiff. I am running 550lb/in springs with an installed angle at ride height of 25 degrees making the effective spring rate about 450lb/in. To get the frequency nearer to 100cpm to be compatable with the front frequency, I would have to install a spring in the 300lb/in range. The load on the spring is right at 1100lbs, and if I were to install 300lb/in springs, they would be compressed 3.6" on a 10" free height spring. I think I am missing something...

Andy