turboAWDfanatic
15+ Year Contributor
- 347
- 29
- Aug 22, 2005
-
Colorado Springs,
Colorado
I guess I just don't understand what is going on here. Isn't the stock ball joint pressed in the control arm from the top? That pic looks like the new one is screwed in from the bottom of the control arm. So the point of this mod is to change the BJ pivot point from the top of the control arm to the bottom? I'm just trying to wrap my head around what is happening here.
The point is to correct roll center on excessively lowered first gen. DSM's. Roll center explained: Google Image Result for http://www.miracerros.com/mustang/t_rollcenter.jpg
Here's a great description from part 3 of Sport Compact Car's greatest tech series ever "Making it Stick":
Roll center affects many critical elements of a car's handling. The most critical are steering input, body roll, balance and mechanical grip.
The center of gravity location (CG) for each end of the car can be found by jacking the car up a known distance on each side while it's on corner scales, and observing the change in corner weights. This data can then be fed into an equation to give you the coordinates of the CG.
Since most people don't have a perfectly flat surface and expensive corner scales, it's usually safe to estimate the CG for the front suspension around crankshaft height in a front-engine car. In the rear, it's usually at the floor of the trunk.
The distance between the roll center and the center of gravity is called the roll couple. The roll couple is the lever arm that centrifugal force working on the CG uses to make a car lean over in a turn around the roll center. In a rear- or mid-engine car, these approximations apply to the opposite end of the car.
The longer the roll couple, the more weight is transferred to the outside wheels during cornering and the more the car will want to roll in a turn. A longer roll couple makes cars slower to respond to steering input. The resulting weight transfer from a long roll couple also uses the inside tires less effectively during cornering, thereby reducing the available grip.
The often-overlooked disadvantage to lowering is that roll center drops more radically than the center of gravity on most cars. This increases the roll couple and can cancel any weight transfer advantage. The huge roll couple created by overlowering will require an overly stiff suspension to control body movement.
You must be logged in to view this image or video.
). What do you think?
