Miata FUCA shock clearance
FUCA (Front Upper Control Arm) shock clearance on 90-05 MX5 Miata
For the 2001 model year (NB2), Mazda added a gusset to the FUCA to increase stiffness. This gusset can contact larger diameter aftermarket shocks at full droop and full bump, resulting in shock damage. The fix is grinding a clearance notch into the gusset or swapping in pre-2001 FUCA. To check clearance, completely assemble and align suspension but leave the front springs out. Disconnect front sway bar and cycle front suspension through full bump and droop travel. Be aware that things flex. The control arms, and bushings can deflect under high cornering loads allowing FUCA to contact shock body eventhough they clear when checked on the hoist. Mininum clearance to shock body should be no less than 4mm. 6mm or more preferred.