[JCunningham]

i have very little to no drone and have headers. i added 2 resonators to quiet it down a little now its pretty decent. the valves started rattling after a few thousand miles like the oem did. there's no drone with the valves closed.

[greg0ry]

Originally Posted by JCunningham

i have very little to no drone and have headers. i added 2 resonators to quiet it down a little now its pretty decent. the valves started rattling after a few thousand miles like the oem did. there's no drone with the valves closed.

Thanks for the info boss

[Camaro 79]

I have the Flowmaster American Thunder NPP. The drone isn't that bad, and with stealth mode it disappears. I had the valve issue, but I fixed it myself and now I don't have the rattle anymore.

With that said, I don't like the sound and wish I had gone another direction. It's advertised as Deep, which it is, but it doesn't have any tone and really loses the throatiness. If I could go back I would not buy it again.

[Chris C 1SS 1LE]

Originally Posted by greg0ry

Wait, watchya mean?!

Have zero drone with my setup and sound tube delete made it quieter inside car. At WOT, yes it is insane. But no drone. Valves open or closed. Does that help?

[ssmofo]

+1 for Borla worth the money. I found mine on Amazon for 730.00

[KingLT1]

Originally Posted by Camaro 79

I have the Flowmaster American Thunder NPP. The drone isn't that bad, and with stealth mode it disappears. I had the valve issue, but I fixed it myself and now I don't have the rattle anymore.

With that said, I don't like the sound and wish I had gone another direction. It's advertised as Deep, which it is, but it doesn't have any tone and really loses the throatiness. If I could go back I would not buy it again.

I know what you are saying...With the valves open, The outlaw mufflers do not sound that good under 3k rpm, it's best to leave the valves closed... but if you have stock headers and cats then it's pretty quiet. Mine sounds really good with cat deletes and the valves closed. I have my NPP tuned to not open the valves until 3k rpm then it sounds great and screams.

IMHO the NPP controller is tuned around the stock NPP. Once you go to a aftermarket NPP exhaust, it's best to tune the NPP valve settings. But that requires tuning software like HPtuners. However It shoudn't void warranty because the NPP settings are in the FSCM controller which is separate from the ECU.

[Camaro 79]

Originally Posted by KingLT1

I know what you are saying...With the valves open, The outlaw mufflers do not sound that good under 3k rpm, it's best to leave the valves closed... but if you have stock headers and cats then it's pretty quiet. Mine sounds really good with cat deletes and the valves closed. I have my NPP tuned to not open the valves until 3k rpm then it sounds great and screams.

IMHO the NPP controller is tuned around the stock NPP. Once you go to a aftermarket NPP exhaust, it's best to tune the NPP valve settings. But that requires tuning software like HPtuners. However It shoudn't void warranty because the NPP settings are in the FSCM controller which is separate from the ECU.

I was actually going to reach out to you to see how the Scavenger X pipe changed your sound and if it solved the issues that I'm having.

It's odd, I didn't like the stock NPP when it was WOT, but appreciated it throughout the rev range. Now, I don't like my exhaust unless it's WOT. The new LT1 just isn't easy to get the sound right

[Abubaca]

Are you still going with the Flowmaster? I've been looking at it, and am curious what your thoughts are. From what I understand, it's got the largest swing from mild to wild, which is part of what I think makes the NPP valuable.



I've heard many people comment on how the "wild" side of this system can have a little drone, which to me is acceptable. I mean really, gotta pay to play, right? ...but on the quiet side, most people seem to report little to no drone, which is the way I'd prefer it. Just what I've heard. I haven't actually heard the system while riding in the car.

It's odd, I didn't like the stock NPP when it was WOT, but appreciated it throughout the rev range. Now, I don't like my exhaust unless it's WOT. The new LT1 just isn't easy to get the sound right

I agree....it's not the best sounding engine, but it ain't bad. I wouldn't trade it! Is the firing order different than the LS engines? Suppose I could look it up.....

[greg0ry]

Originally Posted by Chris C 1SS 1LE

Have zero drone with my setup and sound tube delete made it quieter inside car. At WOT, yes it is insane. But no drone. Valves open or closed. Does that help?

Yes <3

[greg0ry]

Originally Posted by Abubaca

Are you still going with the Flowmaster? I've been looking at it, and am curious what your thoughts are. From what I understand, it's got the largest swing from mild to wild, which is part of what I think makes the NPP valuable.



I've heard many people comment on how the "wild" side of this system can have a little drone, which to me is acceptable. I mean really, gotta pay to play, right? ...but on the quiet side, most people seem to report little to no drone, which is the way I'd prefer it. Just what I've heard. I haven't actually heard the system while riding in the car.





I agree....it's not the best sounding engine, but it ain't bad. I wouldn't trade it! Is the firing order different than the LS engines? Suppose I could look it up.....

I did a bunch of research and at the end of the day it seems like the conclusion for the Flowmasters was that it has a slight drone but not the worst. I ended up deciding to get the MBRP axleback without the valves and I had a feeling that i'm gonna regret it because no valves...until i came across a borla with valves deal that I couldnt pass up so hopefully that's what i'm gonna end up with! Seems like MBRP is mad decent though from the research i've done.

[greg0ry]

Originally Posted by ssmofo

+1 for Borla worth the money. I found mine on Amazon for 730.00

Yeah Borla is da best.

[kropscamaro16]

i have the afe power axleback and it works just fine with npp

[greg0ry]

Originally Posted by Camaro 79

I have the Flowmaster American Thunder NPP. The drone isn't that bad, and with stealth mode it disappears. I had the valve issue, but I fixed it myself and now I don't have the rattle anymore.

With that said, I don't like the sound and wish I had gone another direction. It's advertised as Deep, which it is, but it doesn't have any tone and really loses the throatiness. If I could go back I would not buy it again.

Thank you for the input. I felt like (through youtube videos) .. that the Flowmasters were something just how you described

[greg0ry]

Originally Posted by kropscamaro16

i have the afe power axleback and it works just fine with npp

I looked into that one and it is one of my favorite sounding! At that price though i personally prefer Borla. Any drone on the AFE?