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Bought non-Z51 car off the lot with NPP exhaust. It sounds okay but starting to look at other options. First question I have on this journey is whether to get a cat-back that keeps the AFM/NPP sensors in-tact or go with a cat-back that does not use the valves and get the plugs that, I guess, bypass those systems? Pros/Cons for both if you can.
Keep the AFM/NPP valves functional as they're fully integrated into the car. The AFM valves keep the undesirable noises to a minimum when the car is running in V4 mode, and the NPP valves give you the flexibility to remain quiet-ish, loud, and everything in between.
Here are what I'd consider to be your top-tier choices when it comes to quality & fitment, that retain all 4 valves:
I'm with the others here so far - I kept the valves and got a Borla S-type. No drone when AFM switches to 4 cylinder mode, civilized when I don't want to disturb the neighbors in the morning (or the police officer sitting next to me at the light), loud and deep-throated when that's what I want to hear.
Would love to set you up with an exhaust upgrade! I'm not one to be redundant but yes when you delete the afm valves you'll get a slight annoying sound (it's not really drone it's just an odd frequency) when the car goes into 4 cylinder mode. Some truly hate it. I actually rode in my friends C8 that has a muffler delete/valve delete on his z51 "today" and I was able to experience this sound in real life. It's noticeable. There certainly is drone at cruising speed on the highway with no mufflers or valves. Its not as bad as a muffler delete on let's say a C6 Z06 though. The drone is awful at around 1800rpm.
The one frustration with the 4 valve options is the fact that they are pretty heavy on the wallet $3500-5k+. I do have 15% off instant savings on in-stock Corsa ending 9/15. I have some sweet Corsa dual modes for C8 Stingray in stock.
I also recently introduced a new dual mode catback for C8 Stingray from Level Up Exhaust that's only $2499.99. You can specify electronic valves for full integration into the car's drive modes. Or, you can do the option with the remote valve control that opens and closes the valves with a remote.
Getting rid of valves is a dumb move in my opinion. Unless you are deleting AFM with a tune, the car will sound awful when it drops into V4 mode.
I don't have AFM valves anymore and I can't tell a difference when it's in V4. The only way I even know it's in V4 is because of the light on the dash. I hear no sound difference.
I don't have AFM valves anymore and I can't tell a difference when it's in V4. The only way I even know it's in V4 is because of the light on the dash. I hear no sound difference.
What exhaust did you go with Sweetness? As was proven to me yesterday, there is definitely a change in sound when an afm valve delete C8 goes into 4 cylinder mode. I heard the difference with my own ears. I guess my ears are pretty sensitive and tire / road noise might be louder than this changeover in sound.
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What exhaust did you go with Sweetness? As was proven to me yesterday, there is definitely a change in sound when an afm valve delete C8 goes into 4 cylinder mode. I heard the difference with my own ears. I guess my ears are pretty sensitive and tire / road noise might be louder than this changeover in sound.
I have the Valvetronics Design exhaust. I just got back from a 1,300 mile roadtrip and even specifically tried to hear a difference when it would do the V4 changeover and couldn't hear any change. I feel like I have pretty good hearing but to be honest, when cruising at highway speeds in 8th gear, you can barely hear the exhaust in general anyway (and this is with the main valves fully open, I use simulators for my AFM).
I have the Valvetronics Design exhaust. I just got back from a 1,300 mile roadtrip and even specifically tried to hear a difference when it would do the V4 changeover and couldn't hear any change. I feel like I have pretty good hearing but to be honest, when cruising at highway speeds in 8th gear, you can barely hear the exhaust in general anyway (and this is with the main valves fully open, I use simulators for my AFM).
Got it yeah your system has mufflers so that might help cut some of the frequencies when in 4 cylinder mode. I sold my friend a full valve delete/muffler delete awe track edition.
Got it yeah your system has mufflers so that might help cut some of the frequencies when in 4 cylinder mode. I sold my friend a full valve delete/muffler delete awe track edition.
Yes, you are right, it does have mufflers. Even though when the valves are open it goes straight through (as in you can literally see straight through the muffler), it probably is able to filter out some of the "resonance" or whatever you want to call it.
I have the AWE Track. No valves, just 4 simulators. There is nothing going (rarely) into V4 that I notice, and there is no drone. Drone is purely subjective, and I would guess the same for V4 "sound." To each his own, but no exhaust has better cold start, idle and run sound than the AWE Track, imo. I absolutely wanted ZERO valves, just full 3" straight pipes. Same exhaust on my M4 Comp, and that was all the research I needed. Plus, excellent quality and excellent price.
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