So you’ve purchased a set of coilover bumps for your car with spring pre load (or “spring tension”) modification, but do you know how to effectively set it? Maybe your coilover system does not have separate drive size flexibility, you set it to generate a preferred drive size, and are now just hoping the set pre load is within proper range. Or maybe your coilovers do have spring pre load flexibility separate of drive size flexibility, but you are unsure of how this impacts efficiency. In this article we will explain the results of spring pre load and how to effectively set it.
Having too much or too little spring stress will negatively impact revocation efficiency, but in different ways. Too much spring stress could create your revocation feel like it is leading out. This happens because now the surprise reaches its maximum duration too suddenly, and this may get rid of your wheels from the road surface. Not enough spring stress could create your revocation bottom out excessively. Knowing these results can help create the right adjustments.
Let’s define a few terms to help comprehend spring pre load results. The quantity of action the spring takes in at fixed drive size from the load of your motor automobile is known as “droop.” And the quantity of action remaining over at fixed drive size is known as “compression action.” The complete surprise action is drop and pressure action combined.
Total Shock Stroke = Sagg + Compression Stroke
It is important to comprehend that spring stress does not change the spring amount of a straight line spring (most coilover techniques come with straight line springs). For example, increasing spring pre load WILL NOT boost the stiffness of your straight line spring. However, this WILL boost the quantity of pressure action you have which increases bottoming resistance.
Springs on most coilover techniques have to be pre loaded in to retain a desirable quantity of pressure action at fixed drive size. For example; if you have a coilover with a 200 lbs/in spring amount carrying 800 lbs of bodyweight, without any pre set spring pre load, the coilover will pack 4″ just from the fixed 800 lbs of bodyweight acting on it. If this coilover has a complete of 5″ of action, this only leaves you with 1″ of pressure action remaining over! In this you must pre load the spring to insure you have more than 1″ of pressure action. There is way too much drop in this.
So we now know that spring stress impacts drop. But what is a lot of drop to have? This varies depending on how much complete action your coilovers have, so we treat the drop as a rate of complete surprise action. In to have an appropriate quantity of drop, we recommend setting drop to be 30-40% of the complete surprise action (see formula below). Now you know that you have to modify the spring stress on your coilovers to generate 30-40% droop!
Desired Sagg = Total Shock Stroke x.35
How to set spring pre load:
You must first look at the complete surprise action of your coilover (including the bump stop length). Then evaluate how much the coilover squeezes when your motor automobile is at fixed drive size. Deduct the pressure action at fixed drive size from the complete surprise action to find the drop quantity. Modify spring pre load until revocation drop is between 30-40% of complete surprise action.
Droop = Total Shock Stroke – Compression Stroke