Racing spring rates
03-19-2005, 09:52 AM
#16
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I have 1000# front , 500# rear. weight is 2650#. I use 3012 DA Koni (though I rarely adjust them). The mounts are fabricated,but only the bottom of the backs have a slightly changed location.
Wheels are 12x18 with 335/30s.
I have them, because they were the right deal at the right time. I am happy with them, and perhaps someday will even adjust them....
Wheels are 12x18 with 335/30s.
I have them, because they were the right deal at the right time. I am happy with them, and perhaps someday will even adjust them....
04-08-2005, 12:51 AM
#17
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I came across a website with a clever calculator for determining the spring rate based upon your specific Wheel rate.
Check out www.swayaway.com/main.htm
Then click on the spring rate calculator on the left side of the screen. There is an automatic calculator in the center of the screen. Reference the A-arm suspension for 928 information.
I walked through this with a "suspension expert" and it was very close. The data entered included 2,900 lbs for the car divided by 4 = 725 lbs minus 90 lbs for unsprung weight = 635 lbs per corner
Shock travel on the track is about 4"
Front suspension- Pivot point to shock mount is 6"-----Pivot point to ball joint is 12"------Angle of the shock is estimated at 20 degrees (This is where the 2 to 1 motion ration come in to play on the 928 front suspension)---(The rear motion ratio is 1.5 to 1)
Hit the calculation button---and your desired spring rate is about 1550 lbs.
The rate of shock travel makes a big difference in the spring rate. So if you are on the street andr hitting some pot holes the spring travel may be 8 or 10 inches.... and the resulting spring rate is much less. Interesting tool!!!!
Check out www.swayaway.com/main.htm
Then click on the spring rate calculator on the left side of the screen. There is an automatic calculator in the center of the screen. Reference the A-arm suspension for 928 information.
I walked through this with a "suspension expert" and it was very close. The data entered included 2,900 lbs for the car divided by 4 = 725 lbs minus 90 lbs for unsprung weight = 635 lbs per corner
Shock travel on the track is about 4"
Front suspension- Pivot point to shock mount is 6"-----Pivot point to ball joint is 12"------Angle of the shock is estimated at 20 degrees (This is where the 2 to 1 motion ration come in to play on the 928 front suspension)---(The rear motion ratio is 1.5 to 1)
Hit the calculation button---and your desired spring rate is about 1550 lbs.
The rate of shock travel makes a big difference in the spring rate. So if you are on the street andr hitting some pot holes the spring travel may be 8 or 10 inches.... and the resulting spring rate is much less. Interesting tool!!!!
