[clanky]

I remember a while back reading that people were pulling a certain fuse to have the valves opened all the time in their NPP exhaust. How big of a difference is this compared to just going into the settings and setting exhaust to be in track mode all the time?

[raptor5244]

Fuse 51 for the rear NPP valves. The main difference between Track and the fuse pull will be when you are cruising. In Track mode the NPP valves will still close when you are cruising at low rpm, while they never close when the fuse is pulled. I would just pull the fuse and try it. I many did it because I didn't like the sound of the NPP while giving it light throttle in 7th or 8th gear. The fuse pull solved that for me.

[Ian SS]

As Raptor said, the difference will be heard cruising at low rpm, so realistically freeway driving. I pulled in for 2 weeks and threw it back in. Can't justify giving up the ability to go into stealth on the fly for a louder ride at 75 mph.

[jimmypop13]

You can take control of the valves with a little remote or using ur home link buttons for less than $30 if You build a simple little kit. Or Forza sells one for a little more. I made a post on it in the past. It's a must have mod in my opinion

[Sledgehammer70]

Being able to hear a difference... not so much once your up at highways speeds, but cruising around town at 50+ you will notice it a bit more.

[raptor5244]

Originally Posted by slo_1ss

As Raptor said, the difference will be heard cruising at low rpm, so realistically freeway driving. I pulled in for 2 weeks and threw it back in. Can't justify giving up the ability to go into stealth on the fly for a louder ride at 75 mph.

Yeah, I should mention that I have an A8, which comes with another set of AFM valves. So during typical highways cruising or any steady speed for that matter it switches to v4 mode and the AFM valves close. So, essentially it muffles the exhaust even though the rear NPP valves are open. To me, the loudest thing I hear on highway is tire noise.

On the M6 there are no AFM valves so you will get a little more exhaust noise with the fused pulled then an A8 car.

[jimmypop13]

Originally Posted by raptor5244

Yeah, I should mention that I have an A8, which comes with another set of AFM valves. So during typical highways cruising or any steady speed for that matter it switches to v4 mode and the AFM valves close. So, essentially it muffles the exhaust even though the rear NPP valves are open. To me, the loudest thing I hear on highway is tire noise.

On the M6 there are no AFM valves so you will get a little more exhaust noise with the fused pulled then an A8 car.

Have you ever pulled valve 43 for the afm valves? Sounds hilarious with both sets of valves open when it turns into a Honda with exhaust. It will throw a code though but it goes away a little after you put the fuse back. I did it out of curiosity but I swear the brakes didn't work as well without the back pressure in v4 mode and the bassy drone on the highway was unbearable. It's part of the reason I had to get the afm valves and not delete them when I upgraded to stainless works headers and x-pipe. Would drive me crazy in v4 mode without those valves making it quiet

[LibertyHill]

If one had an excellent custom shop in town to do an exhaust could the stock valves be reused or are they too integrated?