tder1

Just finished my NPP and I have to say it went fairly well. The whole job was 2.5 hours lift up to lift down. FYI, Flowmaster has very good C7 Install Instructions on their Website. Follow them and you'll be OK. Removing the Valance Grills is no trouble, use a hook tool to pull straight out, 3 clips on each side of the Grills. The Reflectors are a little more difficult, 3 Clips on each. Hook under and pull straight out. The trick is not damaging the Paint,Uhggg! Regretfully no pics of reflector clips. One on each end and the middle. Suggest black electrical tape around the opening to guard the Paint. After that it's pretty straight forward. The length of engagement for the pipes is 1.750 so you'll also have to unbolt the 2 bolts holding the pipes to the Transmission to give you wiggle room to separate the pipe assembly, little tight on room to pull them apart though I will say GM did a nice job with the Clamps. The pipes should be well free once you loosen the clamps. I can also confirm that though my C7 has the software for Sound Management, the wiring for the Valves is not present under the Car. These new Valves are Electric only. No more Vacuum. The Valves are default open so if more noise is what your after it's good as is. After looking at another car I believe the wiring is split off the harness at the front valves but that's the second half of the job I will deal with soon. Part Numbers, 20968760 and 20968763 includes Pipes to Tips. I'm Happy with the results. No Drone at any RPM. Good Luck!





In Place, Hangers loose before final Alignment.

Bill17601

NPP is the factory system.. Are you referring to some aftermarket system?

slief

He is referring to converting a non NPP car to the factory NPP exhaust. He included the part numbers for the left and right muffler assemblies.

Good job OP. Let us know if you get the wiring in order so that the NPP functions as it would from the factory instead of always open like it is now.

Zymurgy

It looks to me that your tips are not aligned correctly in any of those photos. In the top photo, which I am guessing is after you were done, the inner tips are higher than the outer tips. They should all be level.

B Stead

For NPP on a non-NPP C7, just get the BB Fusion system and connect the aftermarket NPP muffler valves to either a driver's switch or to the BB C6 vacuum device. (If connecting the aftermarket NPP muffler valves to a vacuum device then the AFM should be disabled. That might be done with the iTune device.)
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ZL-1

C6s had really annoying drone when NPP was left open. But you can leave C7 NPP open 24/7 and it's not really very loud (except that bark on a cold start but it quiets down after about a minute). OP should try it for a week or 2, maybe don't even need to wire up the tip actuators to close ...

Elleby13

thanks for the pictures of the bumper removal

Fordtruck1969

Hi......how is everything going with your npp install? I am considering doing to my 2014.

tder1

Haven't had any issues. The Valves are Open all the time cuz I have not worked on integrating the wiring, just fine with me the way it sounds. I believe if you search here there are threads now on how to connect it and make them open and close. I wouldn't hesitate to do this 3 hour retrofit again.

Fordtruck1969

How is the noise in the cabin? Did the tips level out? Thanks!

tder1

The Tips are just fine. That pic was taken when everything was just put in and not tight yet.
No Problem there. IT'S quiet enough, much quieter than the Corsa on my sons C6. I never find myself wishing they were closed.

Fordtruck1969

Thank you.....that makes my decision a lot easier......appreciate you,Ralph

mrmalcolmj

I have a 2014 Z51 with non NPP option...I was told this couldn't be done (by a few performance shops), converting a non NPP system to an NPP system.

It seems they were wrong. So if i can find an NPP exhaust it is possible to put it on my car?

lakemg

You can physically add the NPP to your car, you just won't be able to electronically select the variable sound level settings that the factory NPP equipped cars are configured to do. So basically the mufflers will be on their loudest setting for you at all times which is not necessarily a bad thing assuming that you are interested in the NPP for louder sound levels.

ErnieD

Akrapovic makes a controller that should work just fine to "intercept" the control signals and control the NPP exhaust (on a non-NPP car) just like the factory NPP setup. Here's a link: https://www.akrapovic.com/#!/car/pro...37&yearId=4241.
Not cheap, but the controller and a used NPP exhaust should still be lower cost than an aftermarket exhaust.

Ernie

mrmalcolmj

That makes sense. What I don't want is a system that is super aggressive, drones and will annoy the old lady.... I considered the BB PRT or Fusion Gen 3 as well but I would need to hear them in person before making the purchase. I'm about to head out to a club meeting I found in the area, hopefully someone has a BB system.

I appreciate the info...I'll also start my search for an NPP system.

lakemg

Coming from the Pontiac G8 GT world, I know drone very well and I do not feel that the NPP system has much drone to it. Perhaps you can get someone with the NPP system to take you a ride with the sound management set to track to give you a feel for what it will sound like. Personally, I like it and actually wish it was a little louder than it is, so it's looking like I'm going to have to add headers at some point to wake the sound up a little more...

mrmalcolmj

Well, one guy I met use to have a BB PRT system and said he got rid of it because it was too loud...however, nearly everyone had NPP so that was a plus. I did get a ride and the drone was minimal in Track/Sport mode and did have the kick i was looking for. I will search for someone selling an NPP system and go from there.

I appreciate the feed back my man.

mcslim

I have C7 NPP mufflers for sale @ $450 cash in NW Houston. Excellent condition. No actuators. Reuse your AFM ones. Open full time. Sounds good but not loud. Will need NPP ones and some kind of control unit to be able to close/control valves. If you want to come down sometime for pick up (will not ship), send me a PM or call 713 468 6145 and leave message. Not sure they will fit inside coupe's hatch area safely for transport? May need truck or? Slim

mrmalcolmj

Sounds good to me, ill contact you tomorrow for more info. I have an SUV as my daily driver so transport should be no issue plus a lot of family in Houston (Fresno, Aldine, Humble, Woodlands).