Standard C7 exhaust experience

[Stingray]

Originally Posted by zimm888

Thanks for the vid, still sounds kinda nasty with those spurts of gas! What exactly is the dual mode feature you're talking about. Is it just when you switch to sport or track and it opens up more?
Doesn't the standard exhaust have valves, or does it not activate in those modes and is only used in Eco?

The standard exhaust has (smaller, orifice-like) exhaust valves found midpipe to deter the unwanted AFM noise when in 4-cyl mode... the NPP has 2 more valves aft of the mufflers, and works in conjunction to the drive modes (or can be manually left fully open via Off mode under Engine Sound Management).


The optional Dual-mode Performance Exhaust (NPP) is explained here by Patrick Herrmann, Chevy's Technical Manager Communications: http://gmauthority.com/blog/2013/10/...anation-video/



"By the way, the Corvette’s standard exhaust system will mark the first usage of Tenneco’s electrical valve technology for sound tuning to provide a unique signature sound when you drive this exciting beast. The electric valves will be working together with the vehicle’s new Active Fuel Management system, which saves gas by switching between four-cylinder and eight-cylinder mode. As the Corvette switches between the two engine modes, the valves will open and close to control the sound of the exhaust.

In addition to those valves, the dual-mode exhaust system will also include the option of two more electrical valves in the tailpipes, tuned specifically for enhanced sound quality. During normal driving conditions, these extra valves will be closed, but they’ll open during harder acceleration, creating lower backpressure, more engine power, and that beautiful Corvette signature sound.

On both exhaust systems, the four exhaust ports feature larger 2.75 inch diameter openings than the 2.5 inch openings on the C6. Both have butterfly valves that open for enhanced performance and sound. The standard system has a 13% improvement in airflow while the optional dual-mode system offers a 27% improvement in airflow."

[Stingray]

Watch Tadge's interview from last night... he talks about the exhaust options when one of the callers asked him a question about NPP's loudness: http://www.corvette7.com/forums/show...20#post7166720

Here's the Non-NPP vs. NPP difference between the two types of C7 axle-back exhausts in exploded-view. Note: the extra actuators between the two.