91-99 MR2 MK2 SW20 FRONT & Rear RCA's(Roll Center Adjusters)
$90.00
These RCA's(Roll Center Adjusters) fiy all 91-99 MR2 MK2 SW20 Turbo And Non Turbo Models.
- 1" Thick
- Complete With All Hardware
- 100% Bolt On, No Modification Required
Designed for vehicles with an extreme drop/Lowered especially SW20's with 17" wheels or bigger.
Not only do these RCA's eliminate BUMP STEER, making a more comfortable ride for the daily driver. But these are crucial for any SW20 that wants to compete on the track. Whether its TIME ATTACK short circuit road racing or drag racing.
The roll center is dramatically lowered, sometimes below ground level when the chassis is lowered drastic amounts that the front lower control arms start pointing towards the sky. When this happens, the car has a greater tendency to induce body roll all from the fact that the roll center becomes too low. At this point, even the benefits of a lower center of gravity from lowering the vehicle becomes outweighed by negatively affecting the roll center.
These roll center adjusters act as a spacer to bring the front lower control arms lower, effectively negating part of the angle lost when lowering the vehicle. Without these roll center adjusters, a drastically lowered SW20 has to rely on its static spring rate to keep the car from rolling over, but unless you are running extreme spring rates, the car will still roll-over because of the suspension geometry.
As a result, weight transfer is decreased and vehicle stability is increased by keeping the roll center above ground-- the higher the roll center is, the better it is for suspension geometry.
When our SW20's are lowered, the geometry of the front suspension becomes altered. The lower the vehicle is, the greater the angles are increased. This greater angle is the cause of the infamous BUMP STEER.
Bump Steer is when your wheels steer themselves without input from the steering wheel. The undesirable steering is caused by bumps in the track interacting with improper length or angle of your suspension and steering linkages.
These Roll Center Adjusters correct the lower A-Arm geometry by keeping the lower ball joints at in there proper distance of articulation.
How Does Roll Center Work?
When cornering, centrifugal force is applied to the car’s CG, which tends to push the car to the outside of a corner. This causes the CG to rotate around the RC. Since the RC is below the CG, cornering force causes the car to rotate AWAY from the force. Hence, the car rolls to the OUTSIDE of the corner.
* When the RC is far away from CG (lower RC), when the car corners the CG has more leverage on the RC, so the car will roll more.
* When the RC is closer to CG (higher RC), when the car corners the CG has less leverage on the RC, so the car will roll less.
* If the RC was right on top of the CG, when the car corners the CG has no leverage on the RC, so the car would not roll at all.
Depending on what the car is doing, you will want one end or the other to roll more or less. You change the height of the RC accordingly to make it closer or further from the CG (which for all intents is a fixed point).
Effects of Front Roll Center Adjustment
Front roll center has most effect on on-throttle steering during mid-corner and corner exit.
* Less on-throttle steering
* Car is more responsive
* Use in high grip conditions to avoid traction rolling
* Use on tracks with quick direction changes (chicanes)
Effects of Rear Roll Center Adjustment
Rear roll center affects on- and off-throttle situations in all cornering stages (entry, mid, exit)
* Less on-throttle steering
* Car is more responsive
* Use in high grip conditions to avoid traction rolling
* Use on tracks with quick direction changes (chicanes)