So you’ve purchased a set of bc coilovers for your car with spring pre load (or “spring tension”) adjustment, but do you know how to properly set it? Maybe your coilover system does not have independent ride height adjustability, you set it to yield a desired ride height, and are now just hoping the set pre load is within proper range. Or maybe your coilovers do have spring pre load adjustability independent of ride height adjustability, but you are unsure of how this affects performance. In this article we will describe the effects of spring pre load and how to properly set it.
Having too much or too little spring tension will negatively affect suspension performance, but in different ways. Too much spring tension can make your suspension feel like it is topping out. This happens because now the shock extends to its maximum length too suddenly, and this may unload your wheels from the road surface. Not enough spring tension can make your suspension bottom out excessively. Knowing these effects can help make the correct adjustments.
Let’s define a few terms to help understand spring pre load effects. The amount of stroke the spring consumes at static ride height from the weight of the vehicle is called “droop.” And the amount of stroke left over at static ride height is called “compression stroke.” The total shock stroke is droop and compression stroke combined.
Total Shock Stroke = Droop + Compression Stroke
It is important to understand that spring tension does not affect the spring rate of a linear spring (most bc racing coilover systems come with linear springs). For example, increasing spring pre load WILL NOT increase the firmness of your linear spring. However, this WILL increase the amount of compression stroke you have which increases bottoming resistance.
Springs on most coilover systems have to be pre loaded in order to retain a desirable amount of compression stroke at static ride height. For example; if you have a coilover with a 200 lbs/in spring rate carrying 800 lbs of weight, without any pre set spring pre load, the coilover will compress 4″ just from the static 800 lbs of weight acting on it. If this coilover has a total of 5″ of stroke, this only leaves you with 1″ of compression stroke left over! In this scenario you must pre load the spring to insure you have more than 1″ of compression stroke. There is way too much droop in this scenario.
So we now know that spring tension affects droop. But what is the proper amount of droop to have? This varies depending on how much total stroke your bc racing coilovers have, so we treat the desired droop as a ratio of total shock stroke. In order to have an appropriate amount of droop, we recommend setting droop to be 30-40% of the total shock stroke (see equation below). Now you know that you have to adjust the spring tension on your coilovers to yield 30-40% droop!
Desired Droop = Total Shock Stroke x.35
How to set spring pre load:
You must first measure the total shock stroke of your coilover (including the bump stop length). Then measure how much the coilover compresses when the vehicle is at static ride height. Subtract the compression stroke at static ride height from the total shock stroke to find the droop amount. Adjust spring pre load until suspension droop is between 30-40% of total shock stroke.
Droop = Total Shock Stroke – Compression Stroke
Aurimas “Odi” Bakchis, is the CEO of Feal Suspension, Inc. and is also a professional race car driver. He has personally engineered Feal Suspension bc coilover systems to perform in a variety of applications and his success on track has proven the outstanding quality of his Feal Suspension products.
Coilover Suspensions – Pros and Cons
Why are they so well known and do they truly enhance the treatment of an auto. In principle, when you bring down your auto, you additionally bring down it focus of gravity consequently lessening body move, along these lines enhancing its taking care of. In any case, taking care of normal for the auto are not just controlled by the focal point of gravity. You additionally need to consider the hosing framework, spring rate, state of the street, side-dividers of your tires, unsprung weight, tire grasp, geometry of the suspension et cetera.
At this moment we are just inspired by the well known coilover set up. There are a great deal of secondary selling producers thinking of various brands and sorts of coilovers. Coilovers are famous with racers because of their adjustability. You can modify the right tallness and now and again you can likewise alter the hosing in this way create eminent taking care of.
There are two sorts of coilovers. They are genuine coilovers and sleeve sort coilovers. Genuine coilovers are a set up where the stuns have a strung body, when as the other one use a ‘sleeve sort’ string. One of the more seasoned, surely understood maker for coilovers is H&R. Presently, there are diverse organizations, for example, Tein, Intrax, and so on likewise making coilovers. In any case, Ground Control was the pioneer of sleeve composed coilovers. We have doubtlessly about the advantages of genuine coilovers. Be that as it may, shouldn’t something be said about the sleeve sort’? Does it work? In principle, it works the same as genuine bc coilovers. In actuality, it doesn’t approach the non coilovers stuns and springs setups.
Ground Control, the pioneer in sleeve plan innovation’ uses aluminum body sleeve with Eibach race springs. The base of the spring is bolstered with a solitary rotational plate with an Allen screw-locking gadget. What’s the issue with this outline you inquire? Like all ‘sleeve sort’ coilovers, there is great chance for the sleeve to pivot and consequently make the spring slip. This can happen to the devotee drivers who like to push the auto as far as possible. The other thing that stresses me is the Allen screw-locking gadget. A screw that little is given the obligations to hold the strain and curve that are produced by the auto when an aficionado drives it.
Weapon-R Tuner 2 coilover change. This one is fundamentally the same with Ground Control aside from it included the additional locking plate (with the same allen fasten locking it place) evidently for included security.
Skunkworks and Arospeed. These two organizations use genuine coilover sort locking gadgets. Twofold plates interlocking each other. This is by a wide margin the best set up yet. Be that as it may, what about the sleeve? Something must be done to secure the sleeve.
These burdens can make thumping clamor, as well as extremely unsafe. Envision this: you are taking corners quick, depending on that enormous buck suspension to do it work, when the sleeve/locking plates moved subsequently making a sudden jar in your suspension (like when you’re driving through harsh street surface) and hence lifted your feel worn out on the ground in this manner losing footing
The correct approach to conform a strung loop over suspension includes utilizing an arrangement of scales. The entire thought of this sort of suspension adjustability is to square with out the heaps on tires (or predisposition them for circle track) for cornering capacity. The way that you can bring down the auto with them is only an additional advantage however it is NOT their essential capacity. You ought to know that you can hurt the execution of your auto on the off chance that you don’t change them at any rate sensibly close. Best case scenario, the auto may not corner and it used to.
If you are after a set of coilovers be sure to check out bc racing outlet for the cheapest prices around.