Stock exhaust to NPP

[TraumaRN1LE]

Hey guys,

Forgive me if this has already been covered. I recently purchased my 2015 SS 1LE and while I love it, the stock exhaust is just too quiet for me. I was wondering if anyone has had any experience switching to the NPP dual mode exhaust from a stock exhaust. I know Ill need to switch out the rear diffuser, but is there any electrical work that will need to be done for the valves on the NPP system? Thanks in advance.

Also fyi I'm stuck in communist California, so after market exhausts are a tad too risky at the moment (unless anyone has experience with a corsa sport or something similar, no headers or anything like that) Thanks!

[steakmaker]

NPP ?

Here's an idea, install some electric cutouts,welded in or band clamps,if band clamps are used,save the pipe that was cut out so you can put it back in when selling the car and you can install them again in your new ride!

[olblue75]

Your 1LE should come with NPP/Dual mode. If anything cut the resonators out.

[Vegas Bound]

I have NPP installed on my car with the ADM controller. Car starts in open mode and use wireless remote to close them. I programmed the wireless to my HomeLink buttons.

[Blueovalman]

Even though you are in California you can still go from the stock exhaust to the SLP Loudmouth or Loudmouth 2 axle back exhaust with 4” tips and you could even install a PowerFlo X Crossover Pipe. All the SLP exhaust parts have a carb number and are 50 state legal. Also SLP exhaust parts come stock OEM on some Chevrolet Camaros so the unnecessary strict smog laws in California can not do anything about it. The SLP exhaust on the 5th gen Camaro sounds outstanding!

[camguynj]

You can’t get a retro-fit NPP system to work like stock because the ECU controls NPP valve operation based on RPM and your car’s ECU isn’t programmed for NPP. You can install just the NPP mufflers (no wiring or tubing required) but you’d always be running in open mode which is the default position for NPP valve flaps.

The only possible ways ? to control the valves would be to get a Forza 3way Controller (always open, closed, or factory/ECUmode). Check with Forza to see if with all the factory NPP piping and muffler components installed including the actuators but without factory NPP ECU programming would the controller work in always open or closed mode only?

If the Forza 3way can’t work then BillyBoat makes a “NPP in a Box” system for vettes that comes with wiring and vaccum tubing. Check with them if it can be installed in a Camaro ? Post a reply with what you find out if you followup with them.

[The Hunter]

I installed headers with catless mid pipes and left the stock exhaust on from the mid pipe back. I also have the mild to wild exhaust controller which takes all of 10 mins to install and I love the sound just smells a little.

[sixty9fordkiller]

Originally Posted by TraumaRN1LE

Also fyi I'm stuck in communist California, so after market exhausts are a tad too risky at the moment (unless anyone has experience with a corsa sport or something similar, no headers or anything like that) Thanks!

yeah, i live in california too and i said "screw your exhaust regulations!" i wanted an exhaust system that if i tried to see the exhaust valves on the cylinder heads from the exhaust tips, i could and i went with that! call me rebelious.


seriously tho, you may be able to find the NPP exhaust in the classifieds section in here. it will bolt/weld right in and will not require tuning. you'll just be in open mode. a very nice sound.

Also, there are also a few other muffler brands that sound really nice with the factory manifolds and factory cats. basically all catback exhaust systems are not illegal in california as long as its after the factory manifolds and factory cats. the only thing you'd have to worry about is getting a citation for your exhaust being too loud so you may want to stay away from exhaust systems that are basically a muffler delete (SLP Loudmouth, etc....)


magnaflow may be too quiet on a stock manifold/cats car. you would barely be able to tell at idle that you have aftermarket exhaust.

if i was staying with stock manifolds and stock cats, id go with borla atak. this guy here is on stock manifolds and stock cats

[SSMY1LE]

Just replace the stock suitcase mufflers with the NPP mufflers and leave the flaps in the default open position. I have the flap controller but never use it.
Best sounding exhaust out there !

[PapaKlutch]

Originally Posted by olblue75

Your 1LE should come with NPP/Dual mode. If anything cut the resonators out.

NPP was an option on all SS's, including the 1LE.

[PapaKlutch]

Originally Posted by TraumaRN1LE

Hey guys,

Forgive me if this has already been covered. I recently purchased my 2015 SS 1LE and while I love it, the stock exhaust is just too quiet for me. I was wondering if anyone has had any experience switching to the NPP dual mode exhaust from a stock exhaust. I know Ill need to switch out the rear diffuser, but is there any electrical work that will need to be done for the valves on the NPP system? Thanks in advance.

Also fyi I'm stuck in communist California, so after market exhausts are a tad too risky at the moment (unless anyone has experience with a corsa sport or something similar, no headers or anything like that) Thanks!

The 5th gen NPP uses the ECU and vacuum lines to control the flaps, so a swap is not something that many go for. There is a company that made an "NPP in a BOX" kit that would allow for always closed or always open. Of course, you have to purchase the NPP mufflers, etc. and a rear Diffuser. Do a google search for NPP in a Box.

I would reach out to others in SO Cal about exhaust upgrades, too. Jump on Instagram and there are several So Cal Camaro groups. You might try WestCoastMaros to start.

[sixty9fordkiller]

Originally Posted by PapaKlutch

I would reach out to others in SO Cal about exhaust upgrades, too. Jump on Instagram and there are several So Cal Camaro groups. You might try WestCoastMaros to start.

come through to the camaro meet this sunday 2/24 at Accelerated Racing in Rancho Cucamonga

10am to 12pm

@12pm we're cruising to Dave n Busters in Ontario for lunch. Fantastic sounds!

WestCoastMaros will be there and a bunch of other camaros as well. you'll get to hear live what you're looking for

[TraumaRN1LE]

Originally Posted by sixty9fordkiller

come through to the camaro meet this sunday 2/24 at Accelerated Racing in Rancho Cucamonga

10am to 12pm

@12pm we're cruising to Dave n Busters in Ontario for lunch. Fantastic sounds!

WestCoastMaros will be there and a bunch of other camaros as well. you'll get to hear live what you're looking for

Awesome!!! Ill definitely see if mom can watch my kids, I didn't know we had local Camaro meets! I'm right down the 210 in Highland!!

[TraumaRN1LE]

Thanks for everyone's responses without flaming me too much . Ill keep looking at options and let you know what I decide to do.