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Does anybody have a suggestion on what coil springs works in the front end of a 56 with a LS 1. This thing is so ridge and firm that I can stand on the front and hardly make it move and I talking 250lbs. And I got the stock springs in it. Anybody got a suggestion. Thanks, Dave
Just mocked up Heidts 2" drop spindles and 1" lowering springs. The front end isn't stiff but the ride height is going to be too high. Crossmember is about 7.5" off the floor. Engine, trans, front fenders, and radiator are on car, but hood, bumper, glass, and interior isn't. I know it will come down some more but I don't think enough. Drivetrain is LS3/T56. I'm going to put some stock springs with 2 coils cut off in it and see what that does.
What state of assembly is your car in? Is it all together, including all sheetmetal, interior, glass and fluids? That stuff adds a LOT of weight to the car.Quote:
Originally Posted by Dvcpps
Here's some calculations for fun. ;) The stock front springs have a 311 lb/in spring rate and the wheel rate is 109 lb/in which means the lower a-arm motion ratio at the spring is about 1.7 (square root of 311/109). The springs are preloaded so they're compressed when the upper a-arm is on the upper a-arm bumper. The front suspension moves 3.5" up and down from ride height at the spindle, which means the spring compresses about 2" (3.5/1.7) from full suspension extension to ride height. The springs have to support about 1800 pounds in front, or 900 pounds each at ride height with the leverage of the a-arm applying it. Therefore the springs need to support about 1530 (900*1.7) pounds of axial load each and should be compressed almost 5" at ride height from free length (1530/311). Further, that means the spring is compressed about 3" and has about 933 pounds of preload on it when the suspension is fully extended and the upper a-arm is on the bumper. Two springs is 1866 pounds. Until you apply 1097 pounds (1866/1.7) over the front wheels to get the upper a-arm off the bumper, the suspension isn't going to move. Once it comes off the bumper, every 218 pounds (2 *109) added over the front wheels will lower the front suspension an inch.
note: I ignored the spring angle because I don't know what it is or how significant it is. I just wanted to show how significant the loads are that keep the upper a-arm topped out until you apply enough weight to the car to get the a-arm off the bumper.
An LS engine is about 150 lighter than an iron SBC as far as I can estimate, so at 218 lb/in front wheel rate the car should sit about 5/8"-3/4" higher than stock.