OK, my exhaust is this:

DC 4-2-1 1 piece header
RandomTech High Flow Cat w/ new gasket put in when I replaced it 30K miles ago
GReddy Evo exhaust

Somewhere during VTEC engagement on a hard acceleration and with the car moving, I get a loud pop and a raspy rattling noise coming from the exhaust note. If I have the car still, with the engine in neutral, and blip the gas past VTEC and the same point the noise normally occours, I don't get the same noise. Before I thought either the cat had broken or a resonator was failing, but that wouldn't make sense because I would think that noise would occour both at a stand-still rev and while accelerating. I'm starting to think that maybe the cat gasket flexes too much under acceleration or a heatshield is going bad (I already removed all the heat shields directly connected to the cat, so I'm thinking it's the heatshield that sits between the cat and the shifter. Anyone know:

1) The torque specs for the spring-over bolts holding the cat to the header, and
2) If I were to strip the heatshield immediately between the shifter and the cat, would I experience any negative side effects?

 

the vehicle will sound differently under a load then it will in nuetral. revving it up in nuetral isnt the best idea either. i have an LS with dc sports 4-1 header random cat and tanabe race medallion catback. its loud as hell but esp when i hit 4-5G i hear a loud raspy noise. it is just the violence of the gasses coming into the collector and throughout the exhaust. i wouldnt strip the shield above the cat. the cat gets really hot you dont want to risk melting anything.