What's going on ls1tech so just recently I installed some hooker headers & I drove it without the catback to the exhaust shop to get it welded & maybe a day after I got the catback on I started hearing this rumbling/banging sound under the car like directly under the middle of the car by the trans it occurs during take off & when I'm under load usually between 2-3k. I replaced my trans mount & it still makes the noise I have pretty decent clearance for the exhaust but I'm not entirely sure if it's hitting anything or not. Any input on that would be great also I my car seems to relatively quiet considering I'm running headers, no cats & the slp lm2 exhaust it has a decent tone to it but not that roaring rumble I was looking to get outta the set up in thinking maybe the exhaust shop did some shitty welds & I also had to re use the stock u clamps wondering why my cars so quiet any input would be helpful thanks ! I had to get the headers welded to the kooks 3.5 inch mid pipe & basically the entire catback welded also including the cme tips maybe the cme is making it quiet ?? Any input is helpful

 

You have a huge amount of growing up to do. There's over 10yrs of learning for you to read up on here.
Exhaust sounds, types to use, size pipes, stainless or mild steel, mufflers, cutouts, over the axle etc etc.
Sound changes with engine mods etc.
A modified engine will always sound better than a standard engine with the same exhaust.
Your's is banging because it's too close to something, it's too quiet because of mufflers used.
Nothing to do with pipe welding or used exhaust clamps

 

Probably your Y pipe

http://lmgtfy.com/?q=Exhaust+banging+WOT+ls1tech

 

Another, "post the thread in the first forum I come to" syndrome......

 

Ur pipes are either hittin ur floorboard and if u want a loud exhaust go true duals with x pipe no mufflers..