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mike100 · 09-13-2014

To answer why the math doesn't add up on the wedge and shim thickness- it is because it isn't just a spacer--the preload or initial tension of the transverse leaf is greater with the stock bushings and shims pushing the center of the spring closer to the ground. There is no lowering of the car per se, as the spring pad on the a-arm and ball joint never move and you always will have the same travel as stock, but all you do is unspring the spring a bit to reduce the spring effort against the a-arms and therefore it drops about an inch.

You might be lowering the CG of the car a bit, but for the most part you are actually reducing the performance of the spring as you now have to compress the car down on it even further to get back to the tension you had stock. The VB&P straight/adjustable spring might be a better choice. Additionally, hacking the bushings off of your hard-to-find ZR-1 stocker is kind of a one way irreversible mod.

As a compromise, I would only remove the shims which will drop it only .5 inches. Don't forget to have the brackets machined shorter if you cut the bushings

09-13-2014	#4
mike100 Join Date: Feb 2011 Location: San Marcos CA Posts: 1,786	Re: Help Lowering My Z To answer why the math doesn't add up on the wedge and shim thickness- it is because it isn't just a spacer--the preload or initial tension of the transverse leaf is greater with the stock bushings and shims pushing the center of the spring closer to the ground. There is no lowering of the car per se, as the spring pad on the a-arm and ball joint never move and you always will have the same travel as stock, but all you do is unspring the spring a bit to reduce the spring effort against the a-arms and therefore it drops about an inch. You might be lowering the CG of the car a bit, but for the most part you are actually reducing the performance of the spring as you now have to compress the car down on it even further to get back to the tension you had stock. The VB&P straight/adjustable spring might be a better choice. Additionally, hacking the bushings off of your hard-to-find ZR-1 stocker is kind of a one way irreversible mod. As a compromise, I would only remove the shims which will drop it only .5 inches. Don't forget to have the brackets machined shorter if you cut the bushings Last edited by mike100; 09-14-2014 at 12:23 PM.