On my 1980 rx7 I have removed the thermo reactor and replaced it with a stock manifold from a 1981 or 82. I had a custom pipe made that reconnected the presilencer to the manifold. My question is with the stock muffler what would be a good replacement for the heavy pre silencer to keep the car running quiet. I am not sure what would happen to the noise level of i just ran a pipe to replace the presilencer?

 

Much louder.

 

You may need 2 presilincers with the stock muffler in this configuration. The thermalreactor acted like a presilencer on its own, LOL.