[Tr6]

Originally Posted by ender2664

If they did it to eliminate drone how does replacing them not add more sound?
Im confused as to why opening up the exhaust doesn't add power and noise, do you know why?
I also assume given your definitive statement this has been tested and verified?

I should've linked the article I guess to clarify what I meant haha. They are very little sections of the pipe and they did engineer the NPP and crushed the pipes at a spot where it wouldn't effect anything is my guess.

Originally Posted by sonnydurden

I think there is some confusion here. You two may be talking about two slightly different things. This weekend I did a custom exhaust on my 1SS. I didn't have NPP, not sure if that makes a difference or not. Anyway I had them cut the exhaust and muffler out right before the crimp. Then I did two separate 3" pipes all the way back with 4" tips. It's way louder. Not sure if more powerful. So my question is did the Mishimoto test remove the crimps and replace with non crimped pipes before the muffler? If so, I wouldn't imagine any change in sound or HP because it's still before the muffler. I'm not an engineer.. This is just a guess.

It really doesn't according to mishi and some others who actually had ONLY replaced the crushed section. Also you removing the muffler which is a massive restriction would add A LOT more sound. Did you also remove the primary or secondary cats? Those removed makes a massive difference as well.

[sonnydurden]

Originally Posted by Tr6

I should've linked the article I guess to clarify what I meant haha. They are very little sections of the pipe and they did engineer the NPP and crushed the pipes at a spot where it wouldn't effect anything is my guess.



It really doesn't according to mishi and some others who actually had ONLY replaced the crushed section. Also you removing the muffler which is a massive restriction would add A LOT more sound. Did you also remove the primary or secondary cats? Those removed makes a massive difference as well.

Thanks man for clarifying! We talked about removing the secondary cats way down the road when my warranty expires!

[Tr6]

Originally Posted by sonnydurden

Thanks man for clarifying! We talked about removing the secondary cats way down the road when I warranty expires!

No problem, hope I didn't come across as a jerk. Never my intention. I am not a keyboard warrior.. lol.

The secondary cats you can remove without causing any warranty issues thanks to them not being monitored. Now primary cats removed = tune. Tune = warranty issues. Gives GM the right to void out warranty (technically, will the dealership tell GM about it? Unlikely).

[sonnydurden]

Originally Posted by Tr6

No problem, hope I didn't come across as a jerk. Never my intention. I am not a keyboard warrior.. lol.

The secondary cats you can remove without causing any warranty issues thanks to them not being monitored. Now primary cats removed = tune. Tune = warranty issues. Gives GM the right to void out warranty (technically, will the dealership tell GM about it? Unlikely).

Oh no, I didn't think you came across bad at all! Thanks for the tip as I might go back for the secondary cat removal!!!

[avalonandl]

The 2005 GTO's had exactly the same except we did not have AFM. I replaced my mufflers with Magnaflows and the resonator with a x pipe. It gave it an exotic sound that screamed at WOT. Loved it.