How does it know?
Is it pressure activated?

It opens at the precise set rpm, right? like at 3000 or someting.

If you put our muffler on a 4th gen. does it still work?
and if it does, how?

 

The muffler probably opens its other flap in response to increasing exhaust flow. People have put it on their 4th gen. Check the general discussion board.

 

As far as I know, it opens at about 2000 RPM at wide open throttle. At this rpm (at WOT) there is sufficient exhaust pressure to open the valve. Under light loads while cruising or non WOT, the valve probably stays shut.

 

u know now in the cold weather when the car is in idle you could see that one pipe is getting much more air coming out of it than the other... as if one is on and the other is off... guess it proves that they ACTUALLY did something... and its not just a marketing gimik!!

 

Here's what Car & Driver had to say in a Technical Highlight describing the 2K Maxima muffler:

"A variable-capacity muffler bows alongside the Maxima's new V-6 (see C/D, June 1999, about the V-6). First seen on the Skyline GT-R sports car (it's sold only in Japan), this muffler has one inlet pipe and two outlet pipes. At part throttle (less than 2000 rpm), a spring-loaded steel valve directs exhaust to one outlet pipe. At wide-open throttle (more than 2000 rpm), the valve opens and directs exhaust to the second pipe, reducing back pressure by as much as 40 percent. The muffler is good for 5 more horsepower on the Infiniti G20. The I30, which shares the Maxima's new V-6, is rated 5 hp higher than the Nissan, thanks to a larger muffler of the same design."