Busy Day

I installed the wheels, nose structure and diffuser. I then realized that the mounting flange on the left nose structure vertical was partially sitting on the extended foot box's weld bead. So, I marked it, took everything apart, cut it on the bandsaw, dressed the edge on the belt sander, and reinstalled everything.

See kids, trigonometry is useful in every day life!

I then set the front and rear ride height which took longer than expected. For each corner:

  • Measure the ride height to determine how much higher or lower the chassis needs to go
  • Roll the car about 18" to center it on the lift blocks (the recessed lift gets in the way when doing the above measurement)
  • Lift the car to reduce the tension on the suspension (it's hydraulic so that's just a matter of pressing the correct button) 
  • Rotate the ride height adjustment collar enough times to make the desired change. This is just a guess. I assume that if I took some careful measurements and applied basic trigonometry I could figure out much each twist equated to
  • Lower the car
  • Roll the car 18" so that a measurement can be taken
  • Measure
  • REPEAT as many times as necessary

Part of the challenge is that when the suspension is at full droop, like when the car is on a lift (or airborne), the spring loses all tension. This allows the lift ram to shift and lose its concentric alignment with the shock. When the car is lowered the lift ram might not seat properly. Not good because it's under tension and hung up on the lip which is going to throw the ride height of by a quarter of an inch or so. This will cause the car to pull to one side... really a bad situation if you get airborne like the dudes in the Ferrari and the car pulls to one side when you land. 

The ride height adjustment collar is the round, gold piece above the green tape

The ride height adjustment collar is the round, gold piece above the green tape

Rear shock. Spring retainer is above the spring and the ride height adjustment collar is below the spring

Rear shock. Spring retainer is above the spring and the ride height adjustment collar is below the spring

The fix is to lift the car, align the lift ram and set the car down again. You want to mind your fingers so that they don't get pinched if it snaps back... dooh! now the other side is off. Even with a push-button lift and a helping hand, this gets tedious fast. Zero-rate springs solve this issue. They have a nominal spring rate and when the suspension is under tension they are completely compressed (i.e., no change to the normal state of things). However, at full drop they apply just enough pressure to keep everything in alignment. So, I need to look into getting a set ASAP. However, to install them I need to remove the wheels, remove one side of the upper control arm, undo the top of the shock, install the new springs and then put it all back together again;-)

While adjusting the rear shocks.... PWANG, WTF just happened? The spring was applying enough pressure on the spring retainer so that as I was tightening the ride height collar I was loosening the spring retainer... until it came off and the spring, which was under tension, was no longer retained! Other than skipping a couple of heart beats, no damage done. Lesson learned, make sure that the spring retainer doesn't spin when turning the ride adjustment collar. It seems to me that Penske should have used a left-handed thread on the spring retainer to prevent this from happening.

I also realized that the sway bar needed to be padded a lot further from the monocoque than I expected because it was hitting the upper control arms This means that the custom pillow blocks that I had machined will need to be replaced. I kept inserting washers until it was in the right position. I then made and installed temporary 3D-printed spacers. I'm not going to machine another set until I'm 100% sure.

The car hasn't been on it's tires in six months... I almost forgot how bad ass low the car when it's sitting on the ground!