Quietest Muffler/Exhaust system
 

Recently I posted a thread about quieting down an NPP stock system. First let me qualify myself here, I am moving into an apartment with an underground garage. My LT headers, LSA, stock cam, on NPP sounds like a very angry monster in there and no “noisy cars” is term in the lease. I love my NPP and will likely keep it in storage for a later day when we buy our next house.

So I have explored Forza and that is an option I am considering. However, I am concerned that it won’t be quiet enough. So this thread is to explore quiet exhaust options, whether it is a catback, axle back or complete system. I am aware of Borla Touring, but not really any other system designed to be quiet when the Camaro market is really about the opposite.

Anyone running something similar to my build but with a quiet exhaust? Looking for ideas, reviews, and sound clips.

npp in closed position is pretty damn quiet, as far as camaro exhausts go lol. id wire in a 3 way switch and close it before startup. it takes about a second for engine vacuum to build and close the valves, but itll work.

The biggest impact in noise with my NPP was when I took out the hi flow cats, holy shit did that get loud even with the flaps full closed.

I saw on Facebook where someone else took a speed engineering true dual exhaust, rearranged it, and installed it so the mufflers (really more like resonators) and x-pipe were between the headers and stock NPP. I did most of it myself and it makes the noise much quieter at idle and low throttle, but it screams when I get into the boost.

However, what I should have done was take it to a professional muffler shop and have them install their own custom solution instead of buying one, modifying it and then having a muffler shop weld the connection to the NPP.



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i would love to see this setup. i am currently running the speed engineering x pipe and shitty glass packs haha. sounds fine, and drone isnt bad with the windows down, but i am wanting to throw my npp back on and am curious to how this is ran?

I don't have any good pictures of mine but here is the Facebook post I saw...

https://m.facebook.com/groups/559684...5353963534077/

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Something to consider.

Get to an exhaust shop and have your NPP Mufflers cut off. Have them weld some V-Bands/Flanges to the NPP's and your existing pipes. Track down either a stock used set of mufflers or another quiet aftermarket MUFFLER ONLY solution and also have V-Bands welded to those.

Now you have an exhaust system that allows you to quickly switch out mufflers at your convenience in less than 45 minutes. You've built yourself a modular solution, while keeping the NPP feature intact for the future.

No, it's not the perfect solution, but it allows you to reuse your existing pipes up to the mufflers without worrying about purchasing an entire expensive aftermarket catback system. You just switch out mufflers at your leisure. Hell, you could build an entire collection of different sounding V-Banded mufflers to change your sound whenever you want!

I also was looking into this at one point and the Magnaflow Resonated X-Pipe Part #11386 seemed to work really well for a lot of guys here.

Check out this thread a guy has a before and after video: https://www.camaro5.com/forums/showthread.php?t=390942

I have my NPP's set up to were I can have the flaps closed before start up. It makes a difference, but not a huge one.

This is all great feedback. I think I am going to find a performance shop that handles exhaust and take it in for a look. I have a few weeks before real winter kicks in.

Also, thinking about the manual forza. Can resell it if I don’t like it and it may come in handy for a lot of reasons.

I would probably just get some smaller resonators put on the npp. Could always have them cut off when you move.

The part number you listed is 2.5 inch. I installed a 3 inch version of this same magnaflow resonated x pipe into my system, and it made very little difference. It took away the raspy snap crackle pop sound and made it deeper in tone. I do like it better now, but it is nowhere near quiet.

I've read a lot of threads where this lowered the noise levels for a NPP exhaust (which is why I listed the 2.5 inch version). I never looked into the 3 inch or how well it works for other exhaust systems. But I never tried it myself I thought about it for awhile. But I love the way my setup sounds even if it is on the loud side so I decided to leave it be. But if I was going to attempt to quite it up a bit the magnaflow resonator would be my choice.