2009 Nissan 370Z: Suspension Walkaround
April 16, 2009
The suspension on our 2009 Nissan 370Z is pretty straightforward. It's got upper and lower control arms and a coil-over shock.
Here you can see what is called a high-mount upper arm. The hub carrier (aluminum here) is huge, and it stretches upwards to locate the upper ball joint high in the fender well. This provides a very large moment arm to counteract side loads generated while cornering. And a large moment arm reduces the forces seen at the upper ball joint. In turn, the upper arm and the body attachment points won't see high loads either, so they can be lighter and stronger.
You can also see how the upper arm slopes down dramatically to the rear. This is called anti-dive geometry, and depending on the angle it can reduce or eliminate brake dive. It would seem that instantaneous caster would increase as the loaded side's upper ball joint moves back during cornering, and that should increase self-aligning forces and generate feedback in turns. But none of the textbooks I own delves into that aspect
Some might call this a double-wishbone front suspension, because it has a one-piece lower arm, too. But a wishbone is either A- or Y-shaped, and this one is L-shaped. It's better to describe this as double control arm suspension.
You can also see that, once again, a forward caliper placement results from a rear-mounted steering rack.
The stabilizer bar link and spring/shock assys (center) mount some ways in from the lower ball joint (left), so neither are 100% efficient. It looks like a 0.65 motion ratio or thereabouts.
But there is something unique going on here. The upper stabilizer link end and the and the lower shock mount bolt to the lower control arm in the same place with a shared bolt.
Moving on to the rear, we can see that this is a multilink design.
Multilink is a catch-all designation that applies when you don't use double control arms or a strut. But links can only hold tension and compression along their axis, so you need many (multi-) of them to orient the wheel.
The 370Z has an upper y-shaped control arm and three links. You can see one of them sprouting behind the brake caliper.
You can aslo see ventilated rear brake rotors and a 2-piston fixed brake caliper. The stabilizer bar is buried deep in the background of the picture, it's end-link attaching about halfway along the upper arm. The twin-tube shock absorber mounts directly to a protrusion of the hub carrier (aka knuckle or upright) for a 1:1 motion ratio.
Here you can see two of the lower links, a black steel one and an aluminum one that has been bloated to double as a lower spring mount.
For fun, I weighed the wheel and tire assemblies and made a few notes while they were off.
Front: 51.5 lbs 19x9 47 mm offset*
Rear: 57.5 lbs 19x10 30 mm offset*
5 x 114.3 mm (4.5 in) bolt circle.
Mind you, these are Rays Forged aluminum wheels, so the wheels themselves shouldn't be overweight. The wheels and tires are simply 19-inch monsters and they're super wide. There's a lot of material here.
Dan Edmunds, Director of Vehicle Testing @ 5,010 miles