Ok, my old exhaust setup consisted of a DC 4-1 header, 2.25" test pipe, custom 2.25" mandrel bent piping with no res., and a straight through fireball style muffler. There were basically no restrictions in the exhaust. I've recently switched back to my stock cat, and an Apexi N1 catback with silencer.

With my old exhaust setup, my header would take a while before it started to get warm. Now with my new setup, it only takes a minute or two b4 it becomes real hot. Could it be because the cat and silencer in my N1 is causing more restriction and heating up the pipes quicker?

 

the cat. more than anything will heat up ur piping faster than anything else..id say keep ur cat. on but then replace the resonator with a straight thru round muffler..then ull be able to run without the silencer without alot of noise

 

So its normal then for a header to warm up more quickly with a cat than without one?

 

ya thats partly how the cat work heats the **** up and burns it basiclly i think

 

correct. it's all with flow and backpressure of how fast the exhaust gases scape out and thru the exhaust sytem. It won't effect much being stock.