phunk

iTrader: (21)

I am curious if anyone knows the exact motion ratio for the rear springs on the 350z? I am setting up for some custom spring rates and I need to know the motion ratio to calculate actual spring rate.

i have done the math but the results i keep coming up with just dont seem right to me.

thanks.

Gsedan35

iTrader: (10)

I knew I had posted it before, ran a search and here's the cut and paste.

Front motion rate is .53 with a 10 degree angle correction needed. (Basically you times the front spring rate by .53 then you times that answer by .96 and that is your actual front wheel rate.

Rear motion rate is .36 for the oem spring location and .59 at the shock/dampner body.

Word to the wise, tuning theories need to be validated, this platform is known to NOT follow what would be a sensible theory if you doing things by the book. But that same book also is what demands validation. Be very mindfull of anyone that tries to take you down a high rear rate road.

phunk

iTrader: (21)

Thanks man.

.34 is what my math came up with, (so we are close there) but its just not adding up for me.

When I use spring rate calculators on existing springs for the car, they are no where near as stiff as a .34 ratio says they should be.

A spring rate calculator is telling me this stock rear spring is a 490# spring, which would give it a wheel rate of 165# at a .34 ratio. That sounds way off to me... no way a stock spring is that soft???