[Road_Warrior85]

Title pretty much explains the whole dilemma.....

But yeah, more power is always great, but I'm not chasing horsepower. I'm more concerned with sound. And since I'm a cheap ass that doesn't like spending money (or really have that much extra to start with)

So since my car has NPP, I dont really want to just ditch it for conventional exhaust. Then I have heard that the stock NPP with valves open flows pretty well as is.

Aftermarket exhausts that retain NPP function are so much more expensive.

So do I get headers and keep the stock NPP exhaust, or do I just get an aftermarket NPP exhaust?


What would/did you do, and why?

[BruceWayne1LE]

Headers are going to require a tune. =bye bye warranty
Headers + tune = equivalent cost of a quality NPP catback

If you want your warranty get an aftermarket NPP
Cost wise to do it right with quality stuff it’s going to cost the same

[s346k]

do you like straight piped farm trucks? that's what it will sound like with the muffler bypassed.

[That1guy_tim]

I personally have long tubes and NPP muffler.. shits loud sounds great and makes power. I would go this route again. changing out an NPP muffler for an aftermarket muffler isn't going to get you anything but noise. A tune will be required with the LT's so unsure if that is a factor for you or not.

[Choda]

I agree. Keep npp as it is and get a nice pair of 2 inch long tubes like csp has. You 100% need a tune to take advantage of the headers.

[2018ZL1]

I like my headers and stock muffler, sounds really nice wide open and in stealth mode its pretty tame!

[Chrome383Z]

I don’t want to void warranty yet so I’m looking at the corsa NPP with dual xpipe. Really want to hear one in person though before $$$. I’ve heard it’s got one of the best quite/loud difference and hopefully doesn’t sound like a farm truck. lol

[ssmike]

If warranty is not an issue go with the headers and stock NPP. More power, more sound and still have the dual function NPP. I have this setup and it sounds great! Really loud at WOT with valves open in track mode and pretty tame cruising around town with valves closed in stealth mode. With just doing aftermarket exhaust you will gain a little sound level and maybe a less raspy sound depending on what you choose, but there is NO gain in power or performance.

[WhiteMale]

I think the track/open setting aside from flow isn't quite loud enough for my tastes though it's impressive as a factory part. I think the new Corsa NPP in comparison claims 12dB over stock track output. Too me the cheapest way to get in to it is with the axle back setup, I don't see that there's anything to be gained with a catback/dual X pipes etc etc until you really get in to headers/tune/forced induction.

[seethruya]

Originally Posted by WhiteMale

I think the track/open setting aside from flow isn't quite loud enough for my tastes though it's impressive as a factory part. I think the new Corsa NPP in comparison claims 12dB over stock track output. Too me the cheapest way to get in to it is with the axle back setup, I don't see that there's anything to be gained with a catback/dual X pipes etc etc until you really get in to headers/tune/forced induction.

I have a 2021 Camaro LT1 with NPP. I did the following two changes.

Change 1: Cut the secondary cats out and cut the NPP system out from the crushed pipe section back. Left the stock 2.75” piping in place including stock crossover. I used a pair of dynomax race mini bullet mufflers. Essentially a custom axle-back setup with secondary cat delete.

https://www.summitracing.com/parts/wlk-24249



Change 2: Ripped everything from the main cats back and replaced all the stock piping with 3” piping from a 3” conversion kit. Continued to use the 6” dynomax race mini bullet mufflers.

https://wildhammermotorsports.com/am...d-engineering/

If I could go back in time, I would have gone straight to Change 2. This is what I learned.

Going from stock (fuse pulled, valves permanently open) to Change 1 gave the exhaust note a much fuller, less tinny sound. The pops and crackles had a stronger bark. It was louder as well from the removal of the secondary cats but more from the force of the sound than decibel level if that makes sense. Even though, this wasn’t enough for me. In the higher rpms, it could still get a tad raspy and unsettled for my taste. Also, I just got the sense having the piping go from 2.75” to 3” to 2.75 to 3” in sections, along with the crushed piping and stock crossover pipe, it wasn’t flowing as good as it could and there would be a further improvement to the sound if I had equal length straight-through piping from the main cats back and a non-stock crossover.

Going from Change 1 to Change 2 gave the exhaust note an even fuller sound and it now stays full, intact, all the way to the 6500rpm redline. The last remaining rasp with some of the pops and crackles was eliminated as well. The exhaust note deepened by a noticeable amount too. I’m 100% satisfied, won’t change a thing until it’s time for headers. As of right now, Change 2 is about as loud as you can get with the stock headers.

I would say don’t be afraid of cutting out the NPP system. Personally, it’s the best stock exhaust system out there but for me at least, I never felt tied to it and even if I removed it, didn’t like the outcome, I could always have it welded back in place and have it operational again.

[Road_Warrior85]

looks like the majority vote is headers with stock NPP..... unless warranty is a concern.

Thats the route I was most leaning too.

Warranty is not a concern.
As I thought about it, my primary goal is sound and my primary concern is cost..... but..... if I was going to spend close to 2 grand and the results were gonna be 1. sound, or 2. sound and power after getting a tune .... then I guess I would be inclined to go the headers route anyway