[Val Walkinshaw]

Relatable.

Cold starts are the best eargasm but once she warms up I feel a bit like "meh". Years ago I installed an axle back Borla S type and while that helped, I still felt like she was just average. Mustangs annoy me and the C8 seems too quiet. I pulled fuse 51 years ago and as of last week just had my cats cut off. She's in the shop right now so I can't verify if that will be the icing on the cake but I hope so. I don't want to be 'that' asshole pissing everyone on the block off but I want more.

[Navigator]

Originally Posted by Val Walkinshaw

Relatable.

Cold starts are the best eargasm but once she warms up I feel a bit like "meh". Years ago I installed an axle back Borla S type and while that helped, I still felt like she was just average. Mustangs annoy me and the C8 seems too quiet. I pulled fuse 51 years ago and as of last week just had my cats cut off. She's in the shop right now so I can't verify if that will be the icing on the cake but I hope so. I don't want to be 'that' asshole pissing everyone on the block off but I want more.

Secondary cats or both?

[Val Walkinshaw]

Originally Posted by Navigator

Secondary cats or both?

Secondary.

Primary requires a tune. Not a road I'm ready to go down yet.

[LT14EVA]

If you pull the fuse, make sure you pull it while the exhaust is open like in track mode.

[arpad_m]

Originally Posted by Val Walkinshaw

Secondary.

Primary requires a tune. Not a road I'm ready to go down yet.

Deleting secondary cats will indeed give you some extra volume. Long tube headers would add another 10 dB or so.

[Joshinator99]

Originally Posted by arpad_m

Deleting secondary cats will indeed give you some extra volume. Long tube headers would add another 10 dB or so.

Agreed. Long tube headers (especially without cats) will be a BIG jump up in volume. It can be a lot depending on what catback you’re running.

[Val Walkinshaw]

Originally Posted by JT6Speed

No extra valves on a manual. We don't need AFM valves because we are always running on 8!

I saw a video back where Phastek was testing some Stainless Works exhaust combos. At 4K rpm in track mode, the stock exhaust put out 101 decibels. Not bad for stock at all.

You can always put the back seats down for more cabin noise

You actually have a good point. I did a rear seat delete 5 years ago and not only does the extra cabin noise sound like music to my ears it actually nearly doubles the space back there and looks damn good.

[Val Walkinshaw]

Originally Posted by Navigator

The valves I can see through the tailpipes are fully open. Is there another set of valves beyond that hidden from view? Or is it just the automatic transmissions (which I don’t have) that have the extra AFM valves?

It's my understanding that as manual owners no, we do not have any other valves (correct term is baffles) beyond what you see between the muffler and the tips.

[Val Walkinshaw]

Originally Posted by arpad_m

Deleting secondary cats will indeed give you some extra volume. Long tube headers would add another 10 dB or so.

I always love it when you chime in. Your knowledge base is so vast, not sure I've ever seen you post something wrong on here.

I didn't realize LT headers only added 10db? I guess I incorrectly assumed they added triple that sometimes to the point of obnoxiousness.

[arpad_m]

Originally Posted by Val Walkinshaw

I always love it when you chime in. Your knowledge base is so vast, not sure I've ever seen you post something wrong on here.

I didn't realize LT headers only added 10db? I guess I incorrectly assumed they added triple that sometimes to the point of obnoxiousness.

Thank you very much

The decibel scale is logarithmic, so "only" +10 dB (going from ~95 to ~105) is a huge difference in terms of sensory experience. In fact, +6dB represents twice the sound wave amplitude, and +10dB is perceived by the human ear as about twice as loud.

That said, long tube headers don't make the car obnoxious, except at WOT where nobody is exposed to it too long as we fly by So it's much louder, but not obnoxiously, and the cabin is surprisingly well insulated already from the factory, so you'll probably want to keep running with the NPP valves open, maybe even flip the rear seat down for extra volume.

[Navigator]

Originally Posted by bishopts

Post a cold start video tomorrow.

https://streamable.com/e82up0

I guess it does sound loud here. It just is a lot quieter on the inside than I recall. From inside the exhaust just sounds very distant and muffled, particularly compared to the GT350 I’m coming from.

[Val Walkinshaw]

Originally Posted by arpad_m

Thank you very much

The decibel scale is logarithmic, so "only" +10 dB (going from ~95 to ~105) is a huge difference in terms of sensory experience. In fact, +6dB represents twice the sound wave amplitude, and +10dB is perceived by the human ear as about twice as loud.

That said, long tube headers don't make the car obnoxious, except at WOT where nobody is exposed to it too long as we fly by So it's much louder, but not obnoxiously, and the cabin is surprisingly well insulated already from the factory, so you'll probably want to keep running with the NPP valves open, maybe even flip the rear seat down for extra volume.

Back seat delete is a permanent solution to the "flip the rear seat down for extra volume" 😉
Fuse 51 I chucked years ago.

Question:
Another poster said when removing fuse 51 make sure to do it in track mode with baffles open. Got me thinking....I've never seen anyone say that before. I know when I did it car was off. Does it matter what mode and if baffles are open or closed?

By the ridiculous amount of soot buildup on my exhaust tips I'm not worried the baffles are closed, just curious.

[wwwdddzzz]

Originally Posted by arpad_m

Thank you very much

The decibel scale is logarithmic, so "only" +10 dB (going from ~95 to ~105) is a huge difference in terms of sensory experience. In fact, +6dB represents twice the sound wave amplitude, and +10dB is perceived by the human ear as about twice as loud.

That said, long tube headers don't make the car obnoxious, except at WOT where nobody is exposed to it too long as we fly by So it's much louder, but not obnoxiously, and the cabin is surprisingly well insulated already from the factory, so you'll probably want to keep running with the NPP valves open, maybe even flip the rear seat down for extra volume.

Here's a chart that illustrates that.

[bishopts]

Originally Posted by Val Walkinshaw

Back seat delete is a permanent solution to the "flip the rear seat down for extra volume" 😉
Fuse 51 I chucked years ago.

Question:
Another poster said when removing fuse 51 make sure to do it in track mode with baffles open. Got me thinking....I've never seen anyone say that before. I know when I did it car was off. Does it matter what mode and if baffles are open or closed?

By the ridiculous amount of soot buildup on my exhaust tips I'm not worried the baffles are closed, just curious.

Its because once it has no power the valves wont move. So if you remove the fuse in a closed position then it will always be in a closed position.

If the valves cycle to open when you turn the car off then it will be open naturally.
So it all depends on the control strategy they use for the actuators.

If you completely remove the actuators then the valves will default open by a mechanical spring.

I have NPP muffler but my car wasn't equipped with it originally so i can't tell you how the operate stock.
https://youtu.be/EG75jiu9J38?si=NdFnAhqL1f3rswvY
Here is a link to mine from a cold start.
Long tubes, no cats, 3in midpipes with xpipe, into stock NPP