3rd Generation Mid-pipe Problem
 

Can anyone tell me what kind of damage could one do if he changes the CAT to a straight pipe on a 3rd generation Rx-7? Bearing in mind that the downpipe and manifold are still stock and that the car is equiped with 3mm apex seals. How serious could the pronblem be? Installing an Apexi ECU and controller would slove the problem?

Blown engine. The problem is it lets the turbo spool too much and you get too much boost for your fuel system and then your engine blows. An apexi ecu will not solve that problem. It will richen up your mix and allow you to tune for your application.

Search the 3rd gen section, this topic has been beaten to death.