Question on front spring rate for coil-overs

[cwmusser]

I have a 1969 Camaro with a TCI front sub frame, LS3 motor with T56 transmission. I also have an Autorad complete radiator module which includes the aluminum core support. All sheet metal is factory with a steel cowl hood. The front end of my car is stiff as a board (very little travel when trying to push down on it). My TCI invoice says 400 lb spring rate. This seems high but I would like to know what others are running with similar specs.
Thanks a lot!

[dondb]

With a 400lb spring rate i would say your shocks are the problem. Take your shocks out and bounce the car....you'll see the springs are easily bounced. What shocks are you running?

[77thor]

400lbs is not high...
For example: My Hotchkis lowering coils have a spring rate of 600lbs.

[cwmusser]

Thank you for the two responses I received. These are coil overs so I can't remove the shocks to check the springs. I feel the answer is needing a higher spring rate.

[Rod]

I have a 1969 Camaro with a TCI front sub frame, LS3 motor with T56 transmission. I also have an Autorad complete radiator module which includes the aluminum core support. All sheet metal is factory with a steel cowl hood. The front end of my car is stiff as a board (very little travel when trying to push down on it). My TCI invoice says 400 lb spring rate. This seems high but I would like to know what others are running with similar specs.
Thanks a lot!

This is pretty common, I see many times to light a spring is included in packages, most think that a light spring is a softer ride, but what happens is you have to compress the spring more to hold up the car, and that makes the coils compress together and that creates coil bind and a rough ride, (springs hold up the car - shocks control ride quality) ideally you want about 1 inch of preload on the spring, if you need more than that you have to light a spring with a TCI chassis I would start you at 600 to 650 lb spring, because of the motion ratio on that shock location, (where the shock mounts on the arm) a stock chassis I usually start 700 to 750 and something like an art morrison chassis is down at 450 to 550......to get a better idea of what you need you have to do some measuring and then use a spring Calculator like this simple Hyperco one (spring calculator) (http://www.hypercoils.com/spring-calculator) hope that helps....here are some replacement springs at reasonable prices also Suspension Geek (http://suspensiongeek.com/t/coil-over-springs-2-12-id)

[rrelco]

I have ridetech 800 lb coil springs in my 66 Elco and just dig the way it rides/handles. if you want i have 650 and 700lb springs that i am not using i will sell them to for a good price just PM me if interested.

[cwmusser]

Thank you very much for this information; extremely helpful. I have to pull my coil-overs off the car and send pictures to TCI. Right now they are saying probably 500 lb but maybe even higher is needed. I'll use the chart you attached to see what I come up with. Thanks again!

[TheJDMan]

You did not specify what shocks you have, are they adjustable or no? If they are adjustable you may have the compression set too stiff. But I agree with Rod you need in the 600# to 650# range. The "Suspension Geek" link Rod provided is a good reasonably priced source for springs.