Guest Chris Posted August 19, 2009 Share Posted August 19, 2009 OK, I recently bought a 2007 C6 convertible with the factory optional "Dual Mode Exhaust" installed. I'm still on cloud 9 and absorbing everything I can learn about my car. But, I've been searching online for hours and finding little info about the C6 exhaust systems, and some of what I've found contradicts other info I've previously found... So, can anyone tell me the difference between the "Dual Mode Exhaust" on my car and the "Bi-Mode NPP" exhaust on the 08-09 C6 models? And what does NPP stand for?What prompted the question was hearing about how to open the dampers on demand on the later models. Some also say it can be done on my 07, but others say it can't be done. Understanding how the systems work will help clear things up for me. Thanks! Link to comment Share on other sites More sharing options...
jstrutt Posted August 19, 2009 Share Posted August 19, 2009 OK, I recently bought a 2007 C6 convertible with the factory optional "Dual Mode Exhaust" installed. I'm still on cloud 9 and absorbing everything I can learn about my car. But, I've been searching online for hours and finding little info about the C6 exhaust systems, and some of what I've found contradicts other info I've previously found... So, can anyone tell me the difference between the "Dual Mode Exhaust" on my car and the "Bi-Mode NPP" exhaust on the 08-09 C6 models? And what does NPP stand for?What prompted the question was hearing about how to open the dampers on demand on the later models. Some also say it can be done on my 07, but others say it can't be done. Understanding how the systems work will help clear things up for me. Thanks! The NPP is just the Option code I believe. Maybe this Link can steer you into some more meaningfull investigation? It may not be too much help. PM BLEW X U to see if he can enlighten you. Link to comment Share on other sites More sharing options...
Jason L Posted August 19, 2009 Share Posted August 19, 2009 I believe they work the same. You can use a "Mild to Wild" switch on it to open all the time or not. It was a great little cheap mod to make the Z's sound better when they first came out before there were many Catback's avail. Link to comment Share on other sites More sharing options...
Marana Rich Posted August 19, 2009 Share Posted August 19, 2009 I know it was on the earlier year C6 Z06, not sure about the Coupe/Convertible.I have an 09 with the option, and the switch John Strutt gave the link to. Link to comment Share on other sites More sharing options...
Guest 06yumavette Posted August 19, 2009 Share Posted August 19, 2009 i hope nobody minds my input but here is what i had looked this up last year before i tried out the Z06 BI MODE SYSTEM...Motor Trend found that the NPP-coded dual-mode performance exhaust system reduces back-pressure by a whopping 80% at high engine speeds, resulting in six additional horses and an improvement of four pound-feet.The Vette was able to scoot to 60mph in just 4.1 seconds. The quarter mile was accomplished in just 12.5 seconds at 115 mph. These numbers are similar to the the results of their testing of the 2002 Corvette Z06!With the new, dual-mode performance exhaust, power output for Coupe/Convertible rises from 430 horsepower (321 kW) and 424 lb.-ft. of torque (575 Nm) to 436 horses (325 kW) and 428 lb.-ft. (580 Nm). This system gives the Corvette a more aggressive exhaust sound character that will appeal to performance enthusiasts.At 3,500 rpm, butterfly valves in two of the four exhaust runners open, backpressure reduces by 80%, and six more horsepower sally forth to the sound of a V8 unleashed.look on the inside two exhaust tips you will see two dump valves or flaps.. at 3500 rps they open using vaccum... if you buy the npp or remote systems that are sold you can control that flap opening when you want not with engine vacuum..if you like it a little louder you would leave it open all the time but.. yes there is a but, if you like that exhaust note you will after awhile get used to it. you will want it louder.. then thats where it can get expensive... i have had three different systems on my car before i settled with the billy boat bullets... the best way to find the exhaust note you are looking for is to hang out with other club members and listen to there cars...one last thing. if you dont like the tone talk with doug bromley from bromleys automotive. he has perfected a way to make it sound just a little better without breaking the bank...HOPE THIS HELPS........ TC Link to comment Share on other sites More sharing options...
Guest 06yumavette Posted August 19, 2009 Share Posted August 19, 2009 here is what it looks like open Link to comment Share on other sites More sharing options...
Jerry Posted February 24, 2021 Share Posted February 24, 2021 So, is the Dual Mode Performance Exhaust Option the same as NPP? Link to comment Share on other sites More sharing options...
SixAddict Posted February 24, 2021 Share Posted February 24, 2021 Yes that’s correct. Link to comment Share on other sites More sharing options...
Dave64 Posted February 24, 2021 Share Posted February 24, 2021 I have that with the NPP exhaust on my C8. It does sound good when in sport mode (it's off in tour mode) and has an 'old hot rod' sound under full throttle, not the 'X pipe' European sound of C5~C7's - to my ears, anyway. It may be because the headers dump almost right into into the muffler and the exhaust tips are spread to the sides of the car rather than grouped together in the middle as with the C5~C7's. Link to comment Share on other sites More sharing options...
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