Suspension/Brakes:

Suspension: The stock setup was somewhat soft, it was great if you wanted the Z as more of a GT coupe, but not for a sportscar. I first picked Eibach springs, they are progressive rate and gave the car a fairly nice ride on the street. They do not perform very well overall in autocross (I did it a few times and thought they were too soft for much improvment on race tires). Along with the eibachs I put on Tokico HP (blues) gas shocks/strut inserts. I was happy for a little while with the car like this... but that changed. I wanted a little more adjustability for autocross events; of course I took this entirely too far. Also I was not satisfied at the stiffness of the eibach springs, they were a nice upgrade for a totally street car. I went for springs from the 1988 "Shiro Special" 300ZX. They are much better overall: Higher linear rate, stock ride height. For better tunability and of course to hold the stiffer springs I purchased Tokico Illumina 5 way adjustable shocks. Big difference overall.

Next the front tension rods were swapped for the better (Z32 style) 88-89 models. Graphite impregnated poly bushings were used as well. The control arms were converted to the 88 style as well; they yielded slightly more negative camber up front and widened the front track about 2cm. Poly bushings now compose the suspension suspension in place of any OEM rubber. I would like to thank Prothane for finally making a poly bushing kit for the Z31, though though they are a pain to install. On the right is a nice little picture of the old bushing "removal".

After putting poly bushings in, I did it again after swapping on control arms from a 1988 300ZX turbo (they are 10MM wider on either side and have to be swapped to use the 87-89 rear brakes).

Brakes: The stock Z31 four wheel disc brakes are more than enough for just about any driving. I upgraded the pads to Axxis Metalmasters, in my testing they proved superior to the other 8 brands I had tested (note: NAPA pads are down right awful) and then I decided to stop wasting money on brake pads because they were good enough. I then bought braided stainless steel brake hoses to replace the soft stock hoses. When I did the swap I flushed the brake system and changed over to high-temp synthetic brake fluid. The hoses and pads made a big change in the braking power as well as pedal feedback. The braking was not bad at this point, but I decided to take it a step further. Fade had only come in noticably during the 3rd hard stop from 100MPH, which is entirely respectable, however not good enough for all out track racing. I was able to boil fluid in under 6 laps with heavy braking.

So I decided to swap over to the 87-89 300ZX Turbo brakes. They are larger up front, with dual piston calipers. The rotors are the same size of the 90-96 300ZX Twin Turbo front rotors. The rears are thicker vented rotors instead of solid. Comparison, old on right and new on left:

I then installed some silly looking cross-drilled and slotted rotors; I noticed very little difference in stopping power and slightly less braking fade (probably mostly because they were thicker than the old rotors):

Drivetrain: Along with the other modifications she now has a Centerforce Clutch mated to a Borg-Warner T5 Transmission from a 1985 300ZX Turbo. I had a driveshaft fabricated with greasable u-joints. I replaced the differential with an R200 clutch-type limited slip unit from a 1988 300ZX turbo car. I rebuilt the unit prior to putting it in.