bimmerborn

It is a good practice to cycle/lube electro-mechanical devices once in a while. For those of us who disabled NPP servos by pulling fuse 41-42 (depending on model year), I suggest put the fuse back and cycle NPP operation half a dozen times. Repeat once a year or more. This should prevent them from permanently get stuck in open position. You might need these servos someday. If you need to lube them apply very small amount of hi-temp silicon based lubricant to butterfly joints. Clean and dry the joint area before lubrication.

Bill Dearborn

Put the fuse back in and use Engine Sound Management to set the Exhaust to Track Mode. The valves will stay open all the time (documented in GM Factory Service Manual and in a picture posted in a thread on the forum). The only time I think the valves close when the system is in track mode is when the engine switches to V4 mode. When in Tour Mode my exhaust is loud from idle to max rpm and the only time I hear it get quiet is when I put the car in Eco mode and the engine switches to V4 mode. Despite all the rumors the valves close at low rpms the fact is they do not and the fuses do not need to be pulled. .





Bill

RobsCountach`

Actually, for controlling drone; there's a valve at the front of the mufflers that shuts in V4 mode.

George_L

Using the settings won't keep the valves open 100% of the time. Track is the most "open", but even in Track the valves will close to pass federal pass-by noise requirements. The fuse pull is the only way to prevent the NPP valve closure. I don't remember the details but Tadge said it was required. If I remember correctly it happens around 30 - 35 mph and revs in the high teens. Don't quote me on the numbers. I've read about this in many discussions and confirmed it with my car.