[raidmagic]

Catchy thread title, huh?

I have an 07 Sierra 5.3. Recently I've had a rattling coming from the drivers side cat. Aside from spending $400 on a replacement y pipe what's my play here? Anyone hollow out your cats? I'm non emmissions so I don't care about that. What other ideas do you guys have for me? Thanks

 

[Klein7]

most on here would say lt with ory back to straight through muffler...

 

[11MPG]

Tried hollowed out. Issue is at 2000-2200 rpms it resonates perfectly to create a mind numbing drone in the cab. Solution is to just cut it entirely hollow it out and run a straight piece of pipe through it. This way you still have the fake cat for inspection. Best option is the long tubes but if you don't have the cash i'd go with the first option.

 

[raidmagic]

Thanks for the heads up on the drone. Don't want that. I've thought about long tunes but it's mostly (cai and a tune) stock and my daily driver so I didn't know if I wanted to open that bag of worms. Is there a recommended header brand?

 

[11MPG]

Pacesetter makes the headers and the Y pipe that lines up in the factory location. Calspeed though makes a set that's similar in quality at a better overall price though. Issue is if you have a seirra classic you are fine. If you have the newer NNBS model then you can only fit the kit on a 2WD
http://www.calspeedperformance.com/mobile/Product.aspx?ProductCode=CSP-Silverado-99-08-Headers

 

[raidmagic]

Mine 2nd nnbs thanks for the link

 

[raidmagic]

Just to update. For the time being I gutted the cats and reinstalled everything. It has a pretty good sound. I also took a 200 mile trip today and it had no resonance while driving on the interstate. I was expecting the worst. After reaching speed and cruising it is no louder than it was stock.

 

[l PATRICK l]

might not be considering it now, but I have pacesetter ceramic coated longtubes, and they are a great investment. i don't run cats, then again our inspection doesn't cover that area luckily

 

[raidmagic]

might not be considering it now, but I have pacesetter ceramic coated longtubes, and they are a great investment. i don't run cats, then again our inspection doesn't cover that area luckily

Oh I'm still ordering them I just needed the truck back together and couldn't wait on them so I did this.