NPP install
Thread Starter
Burning Brakes
Joined: Jan 2011
Posts: 825
Likes: 99
NPP install
I'm looking at a used C7 and was curious if there are any caveats of adding the OEM performance exhaust option to a LT2 that came from the factory without the option. They dealer says it can be added. Would they have to flash the PCM to properly operate the valves? Just not sure it would function like a factory option if added now without all of the computer updates. Dealer wants to sell mthe car so I'm a little skeptical.
Safety Car
Joined: Jan 2014
Posts: 4,496
Likes: 856
From: Walhalla South Carolina
I would think U could add without any PCM affect at all. My friend added it to his 2010 grand sport and has a switch he flips when he wants the baffles open. Should be as easy as that but I could be wrong. Good luck
Melting Slicks
Joined: Sep 1999
Posts: 2,305
Likes: 86
From: Richmond, BC, Canada
Adding an NPP exhaust to a non-NPP car physically is simple.
Merely install NPP valves with the NPP mufflers.
However, the electrical for such a setup is probably a problem.
I don't think the OEM wiring harness for a non NPP car is the same
as an NPP car (but I could be wrong).
So you might have to run a wire which will actuate the valves.
In any event, you will have to install a manual switch to activate them,
from somewhere in the drivers area.
The car software COULD be altered to recognize/work the valves (I guess).
But I suspect this is more effort than it would be worth.
Merely install NPP valves with the NPP mufflers.
However, the electrical for such a setup is probably a problem.
I don't think the OEM wiring harness for a non NPP car is the same
as an NPP car (but I could be wrong).
So you might have to run a wire which will actuate the valves.
In any event, you will have to install a manual switch to activate them,
from somewhere in the drivers area.
The car software COULD be altered to recognize/work the valves (I guess).
But I suspect this is more effort than it would be worth.
Le Mans Master
Joined: Jul 2015
Posts: 6,223
Likes: 1,700
From: Northern California
St. Jude Donor '15
I've read on here that GM will not provide the software upgrade needed to operate the NPP if installed later. You could probably wire it with a switch as suggested, but you won't have the same functionality as factory. It's pretty involved I guess because of the sound management settings. I would be very skeptical.
Thread Starter
Burning Brakes
Joined: Jan 2011
Posts: 825
Likes: 99
I've read on here that GM will not provide the software upgrade needed to operate the NPP if installed later. You could probably wire it with a switch as suggested, but you won't have the same functionality as factory. It's pretty involved I guess because of the sound management settings. I would be very skeptical.
Dazed Confused & Verklemp
Joined: May 2008
Posts: 1,397
Likes: 106
From: Naples, FL & Clear Lake, IA
FYREANT installed it on his 14 2LT without NPP from factory. He said it was a PITA. Believe the hardware/software to control the valves came from an aftermarket source. I would PM him for further details.
