I am planning on replacing the exhaust system on my HF. It is the original from 1990, has two cats from an earlier time in it's life and looking at the rest of the system it is time. I am also having performance issues which on a 62HP car puts it in a league with a riding mower. I suspect this could be because when a new cat was put in the original converter next to the exhaust manifold was not removed and is perhaps clogging.

The original exhaust seems to be 1.5 inch tubing. When my engine dies (225K miles now and showing it). It will most likely get replaced with a motor with a little more HP, perhaps a D16Z6. Does anyone think going with 2.25 tubing now would be an issue with a stock HF motor since I really do not want to replace the exhaust twice.

Mike

 

i don't think it would hurt it . . .
I am coming across the same issue on mine. Just bought a 90 hatch DX with the little muffler and it is practically original, and rusting up. just make sure you have a resonator and decent muffler so you don't get the backfire/popping sound