This is a 12 gauge, CNC laser-cut stainless steel block-off plate for the Series 4 (86-88) 2nd gen RX-7. Turbo and non-turbo cars use the same block-off plate but in different places. The turbo engine EGR is located on the Lower Intake Manifold, while the non-turbo engine's EGR is on the top of the engine itself, on the center side housing. Use a stock EGR gasket and/or silicone gasket material underneath for a positive seal. As with any product that defeats an emissions device, it is intended for off road use only!