NPP Exhaust - Page 2 - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

forzasteve · 07-15-2016, 07:50 PM

If you are installing a NPP exhaust system on a car that did not originally have NPP and you want the valves open all the time ... That is the default. You need not do anything more but to install the exhaust system.

The vacuum is used to close the valves.

Steve

ohyeahjay · 07-15-2016, 08:01 PM

Do you have to change the rear valance for the 2014/15 cars when changing over to the NPP mufflers. I know the 10-13 do however I did not read about the 14/15 year's.

dentnshell · 07-15-2016, 08:02 PM

Yes I changed the rear diffuser to accommodate the dual tips on my 2014 .

ohyeahjay · 07-15-2016, 08:14 PM

what was the part number if you have it handy

Carlitoss · 07-23-2018, 10:20 AM

Hey quick question do you guys happen to know if a 2012 zl1 npp exhaust could fit a 2015 ss? I already bought a 2015 zl1 diffuser

pnwdan · 07-23-2018, 11:48 AM

Why go through all of that to just have it open? Why not just do the muffler delete on your old system for a fraction of the cost?

Fish-man · 07-23-2018, 03:28 PM

I have a 13 L99.
I installed NPP that I picked up cheap (yes they are out there) and left it open... sounded great. not too loud at all.
I then installed LT Headers... now the open NPP is loud as hell! I ended up bolting the valves shut. Sounds about the same sound level as open NPP thru the factory manifold/cats.

pnwdan · 07-23-2018, 04:03 PM

Quote:

Originally Posted by Fish-man

I have a 13 L99.
I installed NPP that I picked up cheap (yes they are out there) and left it open... sounded great. not too loud at all.
I then installed LT Headers... now the open NPP is loud as hell! I ended up bolting the valves shut. Sounds about the same sound level as open NPP thru the factory manifold/cats.

Mine came with NPP. I wired the three way switch so I dont wake the neighbors with my long tubes. I like it in stock mode the best honestly. If you install NPP and keep it open it is the same as no mufflers on the non NPP. If you wire it closed its the same as with mufflers on the non NPP. No real advantage unless its hooked up and running.

Fish-man · 07-23-2018, 05:32 PM

Quote:

Originally Posted by pnwdan

Mine came with NPP. I wired the three way switch so I dont wake the neighbors with my long tubes. I like it in stock mode the best honestly. If you install NPP and keep it open it is the same as no mufflers on the non NPP. If you wire it closed its the same as with mufflers on the non NPP. No real advantage unless its hooked up and running.

Laugh if you want, but i always have an option to leave em open, or even tune it a little by opening it some of the way. Consider yourself lucky to have NPP stock. I think quad tips look better...

DSX_Camaro · 07-23-2018, 05:58 PM

Quote:

Originally Posted by Fish-man

Laugh if you want, but i always have an option to leave em open, or even tune it a little by opening it some of the way. Consider yourself lucky to have NPP stock. I think quad tips look better...

Running the vacuum is easy though. I have to agree with the other poster, running NPP exhaust with no vacuum is just an expensive muffler delete or (valves forced closed) an expensive factory LS3 catback.

UBB · 07-23-2018, 06:35 PM

NPP with pulled fuse and LTH is LOUD!

zz430camaro · 07-25-2018, 02:51 AM

I have factory NPP with the fuse pulled with a cam and headers. Once you get used to it its not that loud until you full throttle it. Just cruising around and sitting at a light its not really that loud at all but sounds good. Just pull the fuse, leave it opened and be done with it, you will like it.

dentnshell · 07-25-2018, 06:15 AM

If you are worried about sound levels inside the car. Sound deadener in just the trunk wheel well dropped my interior noise by 3db as measured from an iphone app. For those that don't do sound 3db is about a doubling or halving of power. Since then I have done under the rear seats and the deck lid as well. Quite a bit inside the rear hips of this girl. Just the cheap noico stuff from Amazon. World of difference inside.

bub · 07-25-2018, 02:13 PM

Quote:

Originally Posted by ohyeahjay

Do you have to change the rear valance for the 2014/15 cars when changing over to the NPP mufflers. I know the 10-13 do however I did not read about the 14/15 year's.

Yes. 22829477 is the P/N. There is a core charge of like $75 to be aware of.

https://www.camaro5.com/forums/showthread.php?t=434175

07-15-2016, 08:01 PM	#16
ohyeahjay Drives: 2022 Camaro LT1 Join Date: Jun 2010 Location: new brunswick Posts: 328	Do you have to change the rear valance for the 2014/15 cars when changing over to the NPP mufflers. I know the 10-13 do however I did not read about the 14/15 year's. __________________ 2024 Shark Skin Metallic LT1 On order 2022 Equinox LT

07-15-2016, 08:02 PM	#17
dentnshell Drives: Black 2014 2SS Join Date: Apr 2015 Location: Oologah, OK Posts: 454 View My Garage	Yes I changed the rear diffuser to accommodate the dual tips on my 2014 . __________________ 2014 L99 2SS. 595HP/571ft-lbs Mods: LSA Conversion 2.5" Upper Pulley, 65# injectors, GPI SS1 Cam, SP Long Tubes, ADM Race Scoop & CAI, NPP exhaust (DIY control), BMR 1" lowering springs, ZL1 Rear Differential / Axles, CF Side Strip / Hood Spear, Tint - Windows / Tails / Sidemarkers, Splash Guards, ADM Boost Gauge, ABL Dashkit, '68 Script Badges, ACS T4 Splitter, ZL1 Rockers from Gary's, Z28 Spoiler, Carbon Fiber Hood Vent, Summer - MRR FS01 Satin Black (10" Front 11" Rear) Winter, pictured-Drag DR 64's Satin Black (9" Front-10" Rear.)

07-15-2016, 08:14 PM	#18
ohyeahjay Drives: 2022 Camaro LT1 Join Date: Jun 2010 Location: new brunswick Posts: 328	what was the part number if you have it handy __________________ 2024 Shark Skin Metallic LT1 On order 2022 Equinox LT

07-23-2018, 11:48 AM	#20
pnwdan Drives: 2014 2SS/RS Join Date: Jan 2018 Location: Washington Posts: 848	Why go through all of that to just have it open? Why not just do the muffler delete on your old system for a fraction of the cost? __________________ 2014 2SS/RS LS3/M6

07-25-2018, 06:15 AM	#27
dentnshell Drives: Black 2014 2SS Join Date: Apr 2015 Location: Oologah, OK Posts: 454 View My Garage	If you are worried about sound levels inside the car. Sound deadener in just the trunk wheel well dropped my interior noise by 3db as measured from an iphone app. For those that don't do sound 3db is about a doubling or halving of power. Since then I have done under the rear seats and the deck lid as well. Quite a bit inside the rear hips of this girl. Just the cheap noico stuff from Amazon. World of difference inside. __________________ 2014 L99 2SS. 595HP/571ft-lbs Mods: LSA Conversion 2.5" Upper Pulley, 65# injectors, GPI SS1 Cam, SP Long Tubes, ADM Race Scoop & CAI, NPP exhaust (DIY control), BMR 1" lowering springs, ZL1 Rear Differential / Axles, CF Side Strip / Hood Spear, Tint - Windows / Tails / Sidemarkers, Splash Guards, ADM Boost Gauge, ABL Dashkit, '68 Script Badges, ACS T4 Splitter, ZL1 Rockers from Gary's, Z28 Spoiler, Carbon Fiber Hood Vent, Summer - MRR FS01 Satin Black (10" Front 11" Rear) Winter, pictured-Drag DR 64's Satin Black (9" Front-10" Rear.)

07-15-2016, 07:50 PM	#15
forzasteve Drives: Love any sports cars Join Date: Mar 2015 Location: Scottsdale, AZ Posts: 286	If you are installing a NPP exhaust system on a car that did not originally have NPP and you want the valves open all the time ... That is the default. You need not do anything more but to install the exhaust system. The vacuum is used to close the valves. Steve

07-23-2018, 10:20 AM	#19
Carlitoss Drives: 2015 2ss Join Date: Jul 2018 Location: California Posts: 4	Hey quick question do you guys happen to know if a 2012 zl1 npp exhaust could fit a 2015 ss? I already bought a 2015 zl1 diffuser

07-23-2018, 03:28 PM	#21
Fish-man Drives: too many to say! Join Date: Nov 2010 Location: S.E. Michigan Posts: 1,013	I have a 13 L99. I installed NPP that I picked up cheap (yes they are out there) and left it open... sounded great. not too loud at all. I then installed LT Headers... now the open NPP is loud as hell! I ended up bolting the valves shut. Sounds about the same sound level as open NPP thru the factory manifold/cats.

07-23-2018, 06:35 PM	#25
UBB Drives: 2018 ZL1 Join Date: Jun 2016 Location: Bismarck Posts: 572 View My Garage	NPP with pulled fuse and LTH is LOUD!

07-25-2018, 02:51 AM	#26
zz430camaro Drives: 2015 1LE Join Date: Oct 2015 Location: Cleveland, OH Posts: 1,485	I have factory NPP with the fuse pulled with a cam and headers. Once you get used to it its not that loud until you full throttle it. Just cruising around and sitting at a light its not really that loud at all but sounds good. Just pull the fuse, leave it opened and be done with it, you will like it.