Rare_Message_7204 t1_iw5ewsq wrote on November 13, 2022 at 2:25 AM

Reply to comment by Jerry_Williams69 in Catalytic converter by Zestyclose_Ad3489

Have you seen a prius header and downpipe? There is a resonator then a straight section with the upstream o2 ... As long as that hasn't been cut out it should have enough back pressure. It will be loud and throw an emissions code but won't run like crap.

Jerry_Williams69 t1_iw5g3zq wrote on November 13, 2022 at 2:35 AM

Yeah no. Have you seen the EGR system on Prius engine? When the O2 sensor(s) doesn't see what it should, it is going to try to send a lot of exhaust gas back to the intake. That won't happen without back pressure. Air fuel ratio will be off. Will cause sluggish performance and reduced fuel economy. Will also see increased combustion temps that can cause the engine to overheat.