Dumb Question NPP
Thread Starter
Instructor
Joined: Mar 2008
Posts: 120
Likes: 3
From: Southern California
Dumb Question NPP
Just got a 2014 Z51, lightly used and very clean...trying to figure out if it has NPP or dual mode exhaust....I am on the infotainment center, that is where you can check the off check correct? It is like I cant click or "unclick" this button, does that mean I dont have it......I know I know you ask well does it sound diff dummy? It doesnt at idle but I think it may on acceleration. I though it would be more noticable
Is there a better way to determine if this car has NPP, dealer was no help LOL
Is there a better way to determine if this car has NPP, dealer was no help LOL
Pro
Joined: Dec 2014
Posts: 529
Likes: 35
From: VA
Also....you should hear a very noticeable difference in tone just at idle. At least I can on my car. The difference in tone is between touring and sport mode (ie weather, eco and touring have the valves closed, and sport and track have them open). It takes about 1-2 seconds for the valves to open/close after changing the mode. Did they not have the original window sticker? I always keep mine, or ask for it when purchasing a vehicle...helps on resale.
Last edited by StingerBG; Dec 22, 2015 at 11:49 AM.
Melting Slicks
Joined: Jan 2004
Posts: 2,299
Likes: 387
From: Fort Worth TX
St. Jude Donor '14-'15
OR you could just lift the rear carpet just inside the rear hatch and check the RPO tag for "NPP" .....4 down - 4 across on my GS, yours will probably be different
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Look at the exhaust just before the tips. If there are valves on the two outer ones, you have NPP. No valves, no NPP.</p><p>Here's some photos of the NPP (and AFM) valves. The AFM valves are before the mufflers and the NPP are the valves after the muffler - right before the exhaust tip:</p><p><img alt="" src="http://img.photobucket.com/albums/v610/talon_90th/NCM%20Bash%202013/DSC_0970_zpsfc957f23.jpg" /> <img alt="" src="http://img.photobucket.com/albums/v610/talon_90th/NCM%20Bash%202013/DSC_0968_zpsf5bb010d.jpg" /></p><p>The NPP valve opens up a less restrictive path through the muffler that results in less back-pressure, more HP and torque and a louder exhaust sound.</p><p>The non-NPP exhaust has the AFM valve and only a single outlet pipe from the muffler that the splits into the 4 exhaust tips. No NPP valve.</p>
Intermediate
Joined: Jul 2020
Posts: 33
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From: South Florida
Look at the exhaust just before the tips. If there are valves on the two outer ones, you have NPP. No valves, no NPP.</p><p>Here's some photos of the NPP (and AFM) valves. The AFM valves are before the mufflers and the NPP are the valves after the muffler - right before the exhaust tip:</p><p><img alt="" src="http://img.photobucket.com/albums/v610/talon_90th/NCM%20Bash%202013/DSC_0970_zpsfc957f23.jpg" /> <img alt="" src="http://img.photobucket.com/albums/v610/talon_90th/NCM%20Bash%202013/DSC_0968_zpsf5bb010d.jpg" /></p><p>The NPP valve opens up a less restrictive path through the muffler that results in less back-pressure, more HP and torque and a louder exhaust sound.</p><p>The non-NPP exhaust has the AFM valve and only a single outlet pipe from the muffler that the splits into the 4 exhaust tips. No NPP valve.</p>