Springs and shocks

Springs and shocks arrived recently from ProParts USA.  When putting together a suspension the actual shocks and springs are just a part of what’s needed.  You want to take a look at how they connect at either end, and take advantage of any improvements possible.

ProParts built a nice set of custom aluminum top hats for the front and rears.  Gone are multiple rubber elements, replaced by spherical bearings.  The front shock lower mount is also a spherical.

One disadvantage of the Koni 30 series is how Bump adjusts.  You have to push this button with the shock fully extended, and “click” it through its range.

In the rear it’s not too bad actually, as the spring is separate.  The front will be trickier with the spring in place.

So I put things together with some spring lengths based off what I’d seen on the always-right Internet.  6″ front and rear.  Of course there is huge variation in this stuff, and 6″ ended up being quite a bit short at both ends.

Here’s how the car looked with the adjusters at max height front,and about the midpoint rear, with 6″ springs:

Heh, yeah, a bit too low.  At this height the front upper control arm is resting on the chassis, and the exhaust is about 1″ undergound (if the car weren’t up on dollies).

 

The above is one I took while the car was like that.  Good news is the bump stop was still about 1/4″ away from making contact.  Yay!  🙂

Based on the path the exhaust takes, I think there’s ~1″ of extra ground clearance to gain by tucking the tubing up closer to those bracing pieces.

The rear spring motion ratio is fairly “soft” on the Z.  As best I can measure, the spring is centered a little bit over 10″ out on ~17.5″ long arm.

Fortunately the shock mounts all the way out at the knuckle, providing great chassis and wheel control.

My approach in springing the Z initially is to go a little stiffer in the front, and a little softer in the rear, compared to the fast 350Z’s that are out there – specifically Brian Peters.  My thinking is the 370 should be making a bit more power than the 350’s.  I want to give the car the best chance it can have of putting it down, especially at a ProSolo.  Most of the other fast Z drivers have abandoned the rear swaybar, but I’ll be keeping one (the Hotchkis piece with lots of adjustments) on there for now.

A week or so after I realized the 6″ers were too short, Jeff had Hyperco deliver a fresh box of longer coils to get the ride height out of the weeds.