slik98z

I helped a friend ( my uncles nephew other side of the family lol) install a set of Mac midlengths on his car this evening...i believe the ypipe it comes with is 2.5 inchs and we put some high flow magnaflow cats (as i get a great discount on them ) in the Y pipe...and of course the first thing he wanted to do when we were done was go rag on it...DOH....first hour or so in the car it sounded great! but after a while i started to hear a rattle. So i got up under the car to see if something came loose and found nothing, then i knocekd on the cat and it made a nasty rattling sound, like something was broken loose in it. I've never heard of that happening.. there was no abnormal signs on the cat of it over heating (like it glowing red or anything), im just wondering if he could have busted the one or both of the screens in the cat. please im not familiar with this kinda stuff, im just one of those guys who helps slap **** on then go for a spin....when **** goes wrong...then im lost....any input?
Thankz
Travis

RPM WS6

iTrader: (3)

Are you sure the 'rattling' was coming from the cat and not somewhere else? I can bang anywhere on my exhaust system and get a vibration/rattle type noise that I think is from the sleeve rings on the O2 sensors, either that or just reverberation in the pipes, because nothing is loose or leaking anywhere......

Can you specifically tell/feel that something inside the cat is making that noise? I've heard of Mac cats breaking apart before (because they are junk), but never the magnaflow cats.....

slik98z

yeah man its the cat, I first thought it was the sleeve ring for the 02 sensor...but ip ulled off the o2 and clamped down on it as best i could and knocked it with my hand and being my uncles nephew is kinda a freak with women...for some reason he had a stethscope hehe, so i was able to use that and when i knocked on the cat, bingo there it was. I did do some welding i was wondering if some metal could have gotten loose in side the cat and is rattling around in there now. its the drivers side cat....but i can bump any part of the exhaust and hear it in the drivers side cat so something has gone majorly wrong with that cat...im just trying to figure otu what exactly so i can think of an approach to fixing this. I dont have access to a welder tomorrow i was thinking about just cutting out the cats and putting a 2.5 inch pipe in its place but i can't get my hands on any piping with 2 slip fit ends on it so id have to use band clamps to but the pipes together and clamp it down...do you think id end up with leakage issues? its loud enough now that whenever teh car is on you can hear it. its bad. and i feel bad cause i helped him do this...so i wanna try to fix it the best i can till i can take it to my buddies shop on tuesday

slik98z

reason im confused is i have magnaflow cats with my lt's and they are worked perfectly, i removed them for sound purposes and will be getting an off road y pipe made out of stainless steal mandrel bent on monday, but i want to keep mine for another project that is in the works....any suggestions?
Travis

gadzookss

Hey, I'm running longtubes with Magnaflow cats and I experienced a similar problem. I was pulling into a gas station that had a slight incline and I knew there would be a possiblility of scraping my driver's side cat. Sure enough I did, I heard a nasty scrape and really didn't think nothing of it until the next morning. I started my up my car and I heard this metallic/rattling sound. I immediatly stopped the engine to check things out. I checked my exhaust tips and I found some ceramic material spewed all over the ground!!! I was shitting my pants. I guess that little bump weakend/cracked the innards and this was the result. I figured I was out a cat and had to replace it. Later on that day I did a couple of WOT runs and wadda ya know, no more noise. The chunk that was making that noise must have blew out. So I think i'm good for now, I don't want to fork out $150 for a new cat if it's not making any more annoying noises. I also got under the car to check out the ding and it wasn't that bad at all. My guess is either you received damaged cats or Magnaflows don't quite hold up well against a beating. Since they are brand new I would probably replace the defective one or hope the chunk comes out on its own. Good luck!

slik98z

so you scraped the cat and it bumped something loose? this sound is stuck right smack dab in the middle, im thinking the front screen may have busted loose or a peice of it and the second one (i htink ther eis one in the front and one in the back and a small bar in the middle if im not mistaken in a magnaflow cat) is stopping it from giong through. Plus he has a flowdisaster catback so im only gonna guess that its not gonna go through that cause it would most likely get hung up in the chambers....

do you all suppose i can just use band clamps and butt the 2.5 inch y pipe to a 2.5 inch pipe and just wrench down on it really well or do you suppose that would just leak like a siv? thanks fellas
T