arbnpx
02-05-2012, 06:24 PM
Something interesting to look at before you consider going wild with suspension mod dreams: http://www.motoiq.com/magazine_articles/id/2313/a-tech-look-under-the-scion-fr-s.aspx
MotoIQ's Mike Kojima got a chance to look under the Greddy car and critique the suspension setup. Some interesting quotes from it:
The FR-S [front] suspension is conventional MacPherson strut. The Greddy car had a prototype set of Greddy coilovers. The only adjustment in the front alignment is the toe which is typical. No provision for camber or caster adjustment is present on the stock car, at least this stock prototype! The front suspension has a good amount of caster, king pin inclination and trail which is good for camber gain under cornering, straight line stability, good on center feel and good self aligning torque with minimal scrub. These aspects of the front end geometry are reminiscent of the Nissan S Chassis and older BMW's, good things.
...due to the angularity of the lower arm when lowered, the front suspension will lose negative camber under roll which will reduce grip and even lead to understeer in a low car unless a lot of static negative camber is dialed in or roll is greatly reduced with stiff suspension. Big negative camber hurts braking traction and causes the car to be road crown sensitive and tramline on cracks and grooves. Being too stiff hurts mechanical grip. Whiteline if you are reading this, this car really needs your long shank ball joints and tie rod ends to correct the roll center. Make some right away please. Maybe your Subaru kit might fit. The best solution before the aftermarket responds might be to not lower the car more than 1.5” or so.
MotoIQ's Mike Kojima got a chance to look under the Greddy car and critique the suspension setup. Some interesting quotes from it:
The FR-S [front] suspension is conventional MacPherson strut. The Greddy car had a prototype set of Greddy coilovers. The only adjustment in the front alignment is the toe which is typical. No provision for camber or caster adjustment is present on the stock car, at least this stock prototype! The front suspension has a good amount of caster, king pin inclination and trail which is good for camber gain under cornering, straight line stability, good on center feel and good self aligning torque with minimal scrub. These aspects of the front end geometry are reminiscent of the Nissan S Chassis and older BMW's, good things.
...due to the angularity of the lower arm when lowered, the front suspension will lose negative camber under roll which will reduce grip and even lead to understeer in a low car unless a lot of static negative camber is dialed in or roll is greatly reduced with stiff suspension. Big negative camber hurts braking traction and causes the car to be road crown sensitive and tramline on cracks and grooves. Being too stiff hurts mechanical grip. Whiteline if you are reading this, this car really needs your long shank ball joints and tie rod ends to correct the roll center. Make some right away please. Maybe your Subaru kit might fit. The best solution before the aftermarket responds might be to not lower the car more than 1.5” or so.