When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hello, I am going to a track day with a 84 db sound limit. Can the factory NPP on a stock 2013 LS3 be forced closed? I don't like the idea of mechanically locking it unless that is only choice. Or maybe the 84 db isn't a problem with the NPP working? Thanks.
Do you have a dashlogic unit? If so, you can leave it in 'quiet' mode and the valves won't open at all, even when it reaches the 3500 rpm point. It can be cycled through the 3 modes with the mirror selector switch.
Do you have a dashlogic unit? If so, you can leave it in 'quiet' mode and the valves won't open at all, even when it reaches the 3500 rpm point. It can be cycled through the 3 modes with the mirror selector switch.
I don't have a dashlogic. Maybe I'll get one. Is it an aftermarket item or stock?
Thanks. I'll look into that. You mentioned the mirror selector switch, is that in conjunction with the dashlogic? Is there any other way to control the NPP without the dashlogic?
You toggle the mirror selector switch in conjunction with the Dashlogic to control the NPP settings. The center position is stock, left is open always I think and right is closed always if I remember correctly.
You use the door lock switch to page through the gauges on the HUD and DIC.
If you pull the NPP fuse it will stay open all the time. I don't think there's any other way to make it stay closed all the time, at least not easily.
Last edited by jesse82nc; Aug 16, 2016 at 08:48 AM.
You toggle the mirror selector switch in conjunction with the Dashlogic to control the NPP settings. The center position is stock, left is open always I think and right is closed always if I remember correctly.
You use the door lock switch to page through the gauges on the HUD and DIC.
If you pull the NPP fuse it will stay open all the time. I don't think there's any other way to make it stay closed all the time, at least not easily.
You toggle the mirror selector switch in conjunction with the Dashlogic to control the NPP settings. The center position is stock, left is open always I think and right is closed always if I remember correctly.
You use the door lock switch to page through the gauges on the HUD and DIC.
If you pull the NPP fuse it will stay open all the time. I don't think there's any other way to make it stay closed all the time, at least not easily.
I have dashlogic, but does the Mild to Wild switch allow to keep the valves closed at all times?
I have dashlogic, but does the Mild to Wild switch allow to keep the valves closed at all times?
Also Mike,
If you have both DL & M2W, the M2W will over ride the DL if you force the valves open with it. The Dashlogic won't be able to control the valves, because the M2W basically opened the circuit (like pulling the fuse).
If you want to use the DL to get all 3 modes of exhaust options, the M2W switch will need to be set accordingly (mild).
Hello, I am going to a track day with a 84 db sound limit. Can the factory NPP on a stock 2013 LS3 be forced closed? I don't like the idea of mechanically locking it unless that is only choice. Or maybe the 84 db isn't a problem with the NPP working? Thanks.
84 db should not be a problem with NPP open. I do not think you have to do anything.
Remove the inner tail light and look straight down in the fender cover void.
Remove the thumb bolt to remove the cover to the NPP solenoid.
Remove the two air lines to the each side of the Npp solenoid, then using the OEM 90* barb connector, connect both lines to each other directly.
Hence you want to connect the end of hose 18 Barb fitting directly to the hose 28, bypassing solenoid 27.
Hence the car sends power to the NPP solenoid to open it up to allow a vacuum to pass through to to close the muffler gates, then kill the power to the Npp solenoid to allow the gates to open up. With a by pass of the solenoid, the gates will stay closed.
Note, there is a vacuum reserve ball in play, and will hold enough vacuum to keep the muffler gates closed when the intake manifold goes to Zero vacuum pressure for the few seconds that you are standing on the throttle WOT it/ to create the zero intake vacuum conditions for a few seconds.
NPP Forced closed?
