I recently traded my 18 2SS for a 17 Stingray w/NPP. I am looking to make the exhaust louder while retaining NPP, and without tuning the car. It sounds terrible with the factory NPP setup. Here's what I have looked at, but I am not sure which path to take;

Headers: This seems to be the best route to make the car much louder, but it's not clear if they can just be bolted on while retaining the factory cats, and if they will cause a lean condition and CEL. - Not clear on how much louder this is, if it requires cutting/welding, or if the factory cats can be retained. I am open to deleting secondary cats if no CEL, but I need to keep the primary
X-Pipe: This seems to change the exhaust tone but not add a lot of volume, it's definitely the most cost effective option, but if it doesn't do what I want it's ultimately pointless. - Not clear on how much louder this is
Axle-Back: This seems to be another great route to making the car louder, but axleback w/NPP is in the $2500+ range then what happens to the AFM valves with these exhausts? - Louder, but the most expensive option
Cutouts: This is what I did in my Camaro and it was perfect. Louder but requires cutting, and running separate cables to the battery to control the valves.

Is there anything I can do that just bolts on and won't cause a CEL, keeps NPP, and gives a substantial increase in volume? Part numbers would be very helpful. I am not against spending the $2500+ on an axleback, but that seems crazy expensive for only part of a full exhaust.

 

ARH makes mid length headers with high flow cats. C7-14134300MLWC They are designed to not throw a CEL and they are a forum vendor. I went with that and a borla catless 60547 x-pipe. Found the borla used and the ARH brand new in box. Both on the forum. No tune. If I need to use my PT Warr I have decided to just reinstall my OEM headers just incase a dealer gives me grief. Complete difference in my 17Z.

 

Sox,
Im looking for a deeper tone without the highway speeds drone. Can you enlighten me here?...is that what you got with your combination?

 

I'd say its about 15% louder with the cat-less x-pipe. For me this was enough of an upgrade. My Borla didn't change the tone - it just added a little bit of extra volume... to me this is how it should have been from the factory. Zero drone - still quiet in Tour mode and sounds great in Track mode. Sadly the cat-less Borla is no longer available but there are other nearly identical options.

I tell people to do the x-pipe first since its cheap and easy. If that is not enough you can start looking into more changes. Since the cats in the x-pipe are not monitored this mod will not throw any CELs or effect the NPP in anyway. Its a true bolt-on.

 

Thanks very much for the info - much appreciated.

 

I went with the ARH Long Tube Catless with NPP and getting used to the sound. It rumbles nice at idle and mild cruising but will also Bark when you jump on it! I went from the the Borla Catless X Pipe and it’s much louder.

 

Thanks very much for the info andybbbb- sounds like what I am after - how is it for drone at highway speeds?

 

I usually will run Highway speeds with NPP closed and it’s very quiet and no Drone in my opinion. If open on Highway speeds it’s a nice low sounding Tone , but drop a gear or two and people’s eyes open wide! Lol

 

literally muffler delete it. its the cheapest and loudest option other than headers. also if you got headers make sure you get a tune after. Also with a muffler delete you will get a little bit of drone but it goes away at highway speeds. Pair that with a ARH header and it will sound MEAN haha. Also these borla axelbacks and stuff really wont make anything significantly louder only just change the tone. I mean youll get like a 5-10 increase in DB but compared to the 20-25 you will get cutting the stupid mufflers off... Cut the cats off along with your muffler if you really want to have that screaming sound when full throttle. The stock OEM exhaust system GM put in the stingrays performance exhaust or not really sucks. good ammount of hp to gain when upgrading or just straight up straight piping it which is always nice. Sounds incredible through tunnels and on track