Hey guys I just recently bought a 2000 civic si from a buddy and he had put full exhaust on it, headers catback all that noise. The problem I'm having tho is at 1500 rpm there is the most obnoxious rattle coming from the exhaust. My friend anda few other people have told me to put in a flex pipe and that will stop the rattle, considering there isn't one in there. If anyones got any input for me that would be great before I go ahead and weld one in

 

check to see if any heat shields are loose.

 

lol typical advice from friends....use flex pipe and that'll stop the rattle hahaha

it's more than likely your heat shields, there are quite a few of them under there and tend to rust and break off around the bolts causing obnoxious rattling.

one other cause if not the heat shields would be the screen inside the resonator

 

Mine did this and it was rubbing on the rear sway bar and when i jacked the car up it wasnt untill i put weight on it..

 

most likely exhaust shields if not that look for rub marks on the piping.

 

Thanks for the replies guys, there happens to be no heat shields down there but it sounds like the rattle is coming from one of the resonators, could something be jazzed up in there?

 

yup, the tack welds inside the resonator that hold the baffle in place usually breaks, especially if your car is lowered and the resonator hits off everything. best thing to do if that is the problem is cut the resonator apart and remove the baffle or get a new resonator

 

I'll check it out when I get home and let you know. Thanks for the help

 

Wise words, i was going to say exactly this myself