NPP Question

sspddmn · 03-15-2022, 11:59 PM

I currently have an AWE track exhaust cat back. My county here just started upping enforcement on vehicle exhaust ordinance thanks to the uptick in sideshows. My question is has anyone Frankensteined their aftermarket non-NPP exhaust with their OEM NPP valves? Meaning has anyone measured and cut out the portion of pipes on the NPP exhaust that houses the valves and then weld them into the aftermarket exhaust? This way I can retain my AWE and use the functionality off the NPP valves. Is this even doable? Spent a lot on this exhaust and I don't want to have to spend another $2300 for a valaved Corsa or Borla. Thanks in advance.

sspddmn · 03-16-2022, 01:16 AM

I currently have an AWE track exhaust cat back. My county here just started upping enforcement on vehicle exhaust ordinance thanks to the uptick in sideshows. My question is has anyone Frankensteined their aftermarket non-NPP exhaust with their OEM NPP valves? Meaning has anyone measured and cut out the portion of pipes on the NPP exhaust that houses the valves and then weld them into the aftermarket exhaust? This way I can retain my AWE and use the functionality off the NPP valves. Is this even doable? Spent a lot on this exhaust and I don't want to have to spend another $2300 for a valaved Corsa or Borla. Thanks in advance.

ST1LE · 03-16-2022, 06:56 AM

The AWE muffler is not chambered, so the valves would not be helpful at all. You need a muffled chamber to direct the air through, like the NPP mufflers you mentioned have 2 chambers, with on being more muffled than the other.

I think your only option is selling the exhaust and replacing with an NPP muffler.

mariojas · 03-16-2022, 06:59 AM

Fun fact - Dodge has just a flap in the piddle of exhaust pipe... You could experiment I guess.

WhiteMale · 03-16-2022, 06:59 AM

I dont see why that couldn't be done in a muffler shop but no I've not seen any one on this forum do it.

Drnick · 03-16-2022, 07:36 AM

You reside in California ( San Fran area)?, if so, cops have nothing
Better to do? Enforce noise restrictions on cars?
Hmmm, very interesting.

sspddmn · 03-16-2022, 08:27 AM

Quote:

Originally Posted by Drnick

You reside in California ( San Fran area)?, if so, cops have nothing
Better to do? Enforce noise restrictions on cars?
Hmmm, very interesting.

Yes that's why it's called Commiefornia. Trust me, I know. 5 more years till retirement then I'm outta this shit hole

KingLT1 · 03-16-2022, 09:53 AM

The easiest solution without changing exhaust systems would probably be to order the AWE touring mufflers (which should bolt in), then add E cutouts up stream of them when you want loud.

sspddmn · 03-16-2022, 10:07 AM

Quote:

Originally Posted by KingLT1

The easiest solution without changing exhaust systems would probably be to order the AWE touring mufflers (which should bolt in), then add E cutouts up stream of them when you want loud.

I was thinking that too but as a last resort cost wise. Thanks!

ST1LE · 03-16-2022, 11:21 AM

Quote:

Originally Posted by sspddmn

I was thinking that too but as a last resort cost wise. Thanks!

Magnaflow makes a mid section muffler you could install, but you lose the optionality with NPP. Its about $150 for the part, so a cheap option in the short term if you have to find a fix quick.

sspddmn · 03-16-2022, 02:25 PM

Quote:

Originally Posted by ST1LE

Magnaflow makes a mid section muffler you could install, but you lose the optionality with NPP. Its about $150 for the part, so a cheap option in the short term if you have to find a fix quick.

Cool thanks for the info.

serper3 · 03-16-2022, 05:42 PM

I don't think it is doable because its not the valves themselves that quiet the exhaust.. the muffler in your awe would have to be designed with npp in mind. there would have to be a loud straight through section in the muffler, and a quiet side in the muffler. so i do not think it would work on an exhaust that was not designed to work with npp.

i would try to find someone who has an npp exhaust and wants to trade.

arpad_m · 03-16-2022, 07:08 PM

^^^ this, the exhaust needs two clearly separate paths, you can't just slap a valve into a single resonated path.

By the way, several of us here tried to tell AWE that they should offer a valved solution, to no avail (the funny thing is they already manufacture valved exhausts for other cars, just not the Camaro...)

sspddmn · 03-17-2022, 01:37 AM

Yeah I figured as much. Thanks for the info guys.

03-15-2022, 11:59 PM	#1
sspddmn Drives: 2018 ZL1 1LE and 1991 Z28 Join Date: Jan 2009 Location: SF Bay but from the 808 Posts: 1,086	NPP Question I currently have an AWE track exhaust cat back. My county here just started upping enforcement on vehicle exhaust ordinance thanks to the uptick in sideshows. My question is has anyone Frankensteined their aftermarket non-NPP exhaust with their OEM NPP valves? Meaning has anyone measured and cut out the portion of pipes on the NPP exhaust that houses the valves and then weld them into the aftermarket exhaust? This way I can retain my AWE and use the functionality off the NPP valves. Is this even doable? Spent a lot on this exhaust and I don't want to have to spend another $2300 for a valaved Corsa or Borla. Thanks in advance. __________________ In the garage: 2018 HBM ZL1 1LE // 2013 ZL1 (sold) // 1991 Camaro Z28 5.7L // 2022 Audi E-tron SUV (wife's car) // 2002 Camaro SS (sold)

03-16-2022, 01:16 AM	#2
sspddmn Drives: 2018 ZL1 1LE and 1991 Z28 Join Date: Jan 2009 Location: SF Bay but from the 808 Posts: 1,086	NPP Question I currently have an AWE track exhaust cat back. My county here just started upping enforcement on vehicle exhaust ordinance thanks to the uptick in sideshows. My question is has anyone Frankensteined their aftermarket non-NPP exhaust with their OEM NPP valves? Meaning has anyone measured and cut out the portion of pipes on the NPP exhaust that houses the valves and then weld them into the aftermarket exhaust? This way I can retain my AWE and use the functionality off the NPP valves. Is this even doable? Spent a lot on this exhaust and I don't want to have to spend another $2300 for a valaved Corsa or Borla. Thanks in advance. __________________ In the garage: 2018 HBM ZL1 1LE // 2013 ZL1 (sold) // 1991 Camaro Z28 5.7L // 2022 Audi E-tron SUV (wife's car) // 2002 Camaro SS (sold)

03-16-2022, 06:56 AM	#3
ST1LE Drives: E92 BMW M3 Join Date: Oct 2012 Location: Houston Posts: 4,496	The AWE muffler is not chambered, so the valves would not be helpful at all. You need a muffled chamber to direct the air through, like the NPP mufflers you mentioned have 2 chambers, with on being more muffled than the other. I think your only option is selling the exhaust and replacing with an NPP muffler. __________________ SOLD - 2013 1LE - Pat G Spec'd Cam, NPP with 1 7/8" Long Tube Headers with High Flow Cats, Intake w/scoop, Ported Throttle Body, and Apex 1.25" Lowering Springs. J-Rod Built and Matt@FSP Tuned

03-16-2022, 06:59 AM	#4
mariojas Drives: 2022 ZL1 M6 & 2023 Stinger GT AWD Join Date: Nov 2021 Location: Detroit Metro, MI Posts: 452	Fun fact - Dodge has just a flap in the piddle of exhaust pipe... You could experiment I guess. __________________ 2023 Kia Stinger GT AWD - as a family car... 2022 ZL1, M6 as daddy's ass mover Charger sold! Better to sell, than waiting to be stolen...

03-16-2022, 09:53 AM	#8
KingLT1 Drives: 2016 1SS NFG A8 Join Date: Aug 2017 Location: 46804 Posts: 7,666	The easiest solution without changing exhaust systems would probably be to order the AWE touring mufflers (which should bolt in), then add E cutouts up stream of them when you want loud. __________________ 2016 NFG SS A8/Whipple 2.9/Fuel System/Flex Fuel

03-16-2022, 06:59 AM	#5
WhiteMale Drives: 23 ZL1 A10 Rapid Blue Join Date: Aug 2020 Location: MO Posts: 2,260	I dont see why that couldn't be done in a muffler shop but no I've not seen any one on this forum do it.

03-16-2022, 07:36 AM	#6
Drnick Drives: 22’ ZL1 Join Date: Dec 2021 Location: Florida Posts: 450 View My Garage	You reside in California ( San Fran area)?, if so, cops have nothing Better to do? Enforce noise restrictions on cars? Hmmm, very interesting.

03-16-2022, 05:42 PM	#12
serper3 Drives: 2018 Camaro ZL1 1LE Join Date: Mar 2021 Location: Bay Area, CA Posts: 288	I don't think it is doable because its not the valves themselves that quiet the exhaust.. the muffler in your awe would have to be designed with npp in mind. there would have to be a loud straight through section in the muffler, and a quiet side in the muffler. so i do not think it would work on an exhaust that was not designed to work with npp. i would try to find someone who has an npp exhaust and wants to trade.

03-16-2022, 07:08 PM	#13
arpad_m Drives: 2018 Camaro 2SS A8 Join Date: Jul 2017 Location: East Tennessee Posts: 13,477 View My Garage	^^^ this, the exhaust needs two clearly separate paths, you can't just slap a valve into a single resonated path. By the way, several of us here tried to tell AWE that they should offer a valved solution, to no avail (the funny thing is they already manufacture valved exhausts for other cars, just not the Camaro...) __________________ 2018 Camaro 2SS — G7E MX0 NPP F55 IO6 735 rwhp \| 665 rwtq Magnuson TVS 2300 80mm pulley \| Kooks 1 7/8" LT headers \| JRE smooth idle Terminator cam \| LT4 FS & injectors \| TSP forged pistons & rods JMS PowerMAX \| DSX flex fuel kit \| Roto-Fab CAI \| Soler 95mm LT5 TB \| 1LE wheels \| 1LE brakes \| BMR rear cradle lockout \| JRE custom tune 1100 - 1/30/18 \| 2000 - 1/31/18 3000 - 2/06/18 TPW 2/26/18 3400 - 2/19/18 \| 3800 - 2/26/18 4300 - 2/27/18 \| 4B00 - 3/01/18 4200 - 3/05/18 \| 4800 - 3/14/18 5000 - 3/16/18 \| 6000 - 3/19/18

03-17-2022, 01:37 AM	#14
sspddmn Drives: 2018 ZL1 1LE and 1991 Z28 Join Date: Jan 2009 Location: SF Bay but from the 808 Posts: 1,086	Yeah I figured as much. Thanks for the info guys. __________________ In the garage: 2018 HBM ZL1 1LE // 2013 ZL1 (sold) // 1991 Camaro Z28 5.7L // 2022 Audi E-tron SUV (wife's car) // 2002 Camaro SS (sold)

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