Odd exhaust issue, sound has changed

nsadams87xx

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Hi everyone, this is my first post in the forum. Long time reader and I thought I'd post this issue since everyone is so incredibly savvy here.

Yesterday I noticed an odd change in my exhaust tone.


Setup:
Kooks 1 7/8" long tubes - been on the car since February
Kooks high flow catted X pipe - been on the car since February
Magnaflow Competition Catback - just over a year old
All clamps checked (except for header bolts)



I normally have a loud crisp race car bark that growls and echoes off of buildings and it's euphoric. If anyone has heard ARH headers and the Magnaflow Competition catback together, it sounds almost exactly like that. But what I got yesterday was the same deep low rumble, the same mid rage growl but accompanied with a nasty rice burner-like rasp. It's the same awful sound that can be described as that tin can raspy buzzing/rattling when your local rice burner hits the loud pedal at an intersection. I've checked all my connections. I did make a few WOT pulls the day before but didn't notice until yesterday. My parameters look fine still, AFR is good, timing hasn't changed, and nothing's overheating. No CEL's. But even though there are no CEL's I'm almost wondering if one if maybe one of my cats are starting to fall apart. It only starts happening at around 2700'ish RPM when the engine starts to get a little stressed or loaded like on an incline grade up a hill. If I rev up normally on a straight flat surface it sounds fine, granted it can be hard to hear. Any thoughts?
 

Flapjack

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Are the Magaflows chambered, or do they have packing?

Sounds like you might've blown the packing out, or it's otherwise coming apart....

Sent from my Verizon Galaxy S4
 

nsadams87xx

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I know I should really check the cats. I just wanted to make sure I didn't overlook anything. I live in an apartment building and I don't have a lot of room in my parking area to get under the car and take off the mid pipe to check. Have to catch a time when the people next to me are gone.
 

86GT351

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If you remve them and look you might not see anything directly. Have you thought about contacting Kooks? Call and ask to speak with Drew!
 

fdjizm

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Kooks cats are known to suck actually. (damn shame for what the setup costs)
I'm not even going to post the horror pics for your peace of mind, but get the cats checked lol.
 

nsadams87xx

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Kooks cats are known to suck actually. (damn shame for what the setup costs)
I'm not even going to post the horror pics for your peace of mind, but get the cats checked lol.


Unfortunately I think I hear you out. I've seen some bad ones before and did my homework before choosing to go the high flow cat that route. But I usually felt ok because I heard more horror stories from other companies than Kooks cats. The car still runs completely normal and pulls just fine and as expected. I know if a cat is collapsing on itself and clogging, I'd DEFINITELY know. So...I don't know. It's pretty puzzling and frustrating.
 

fdjizm

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If it feels OK it's probably not "clogged" but you could have blew a few chunks out and that would give you your louder sound.
 

nsadams87xx

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If it feels OK it's probably not "clogged" but you could have blew a few chunks out and that would give you your louder sound.


That's what I would have expected. I gave my car the beans this morning (carefully) just to see how it was running and it felt no different. Just that really bad sound once the engine gets a bit loaded. Oh and I didn't mention that my car actually sounds quieter now in the upper frequency tones but sounds perfectly normal in the mid and low range tones. And the idle and cold start sound normal too. I just had a really embarrassing thought/troubleshooting idea too: I haven't ever drained my axle backs of water. :oops:
 

86GT351

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Kooks cats are known to suck actually. (damn shame for what the setup costs)
I'm not even going to post the horror pics for your peace of mind, but get the cats checked lol.

They have a totally new design they use now!
 

JEWC_Motorsports

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Magnaflow hi-flow cats are good pieces, kooks suck!!!!!!!!! Check your cats before you end making a "I just blew my engine thread."
 

nsadams87xx

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I took my exhaust apart. It's the axle backs. Started the car up after taking it off piece by piece. But we knew right away after taking just the axle backs off that they were the issue.

http://www.youtube.com/watch?v=ljosTtzHY3g
Pretty sure this doesn't sound like a clogged cat...

Either way, I have NEVER heard of an exhaust getting quieter especially straight through designs.
 

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