mundo

I've converted my '05 LS2 based car to LS7 exhaust manifolds, cats and H pipe. Initially I connected them to my old 2.5" catbacks via a reducer.

I just purchased a hardly used set of GM stock NPP catbacks that were on an '09 Z06. I know nothing about the NPP except what I've heard. At < 3500 rpm the valves are closed but above 3500 the valves open making for better sound and flow.

Can someone please describe how the valves are operated / actuated in a stock car. Are they vacuum driven? Do I have to run vacuum lines the length of the car to the actuators? Is it electrically driven. I would prefer to have them automatically driven with a manual override. What does a mild to wild controller do and how does it operate? Does anyone have a diagram of the hook up / connections?

Thanks in advance
Mundo

RicK T

Yes you need vacuum and a controller.

Check out this thread and the posts from Sunset Orange Creations and his website:

http://forums.corvetteforum.com/c6-c...ectronics.html

Top_Fuel

Just so you don't get confused, "NPP" mufflers and Z06 dual-mode mufflers are not the same. What you have is Z06 dual mode mufflers. These are actually different internally than NPP mufflers. The Z06 mufflers have a perforated internal pipe which quiets them down some. The NPP internal pipe has no perforations. Some people will modify their Z06 dual-mode mufflers by cutting them open and covering up the perforated pipe. It makes them sound louder when the baffles are open. You can check out the Z06 muffler mod HERE.

FYI...(more info thatn you wanted to know )...ZR1 dual-mode mufflers do not have a perforated internal pipe and require no modification top be loud. In 2012, all Z06s started being built with ZR1 mufflers.

Cedarberry