Was driving home from school tonight through some stop-and-go and traffic. In front of me was a 330 CI. It had 2 pipes coming out of one muffler, and it looked like the pipe on the right was closing when the car came to a stop, and opened again once he was going about 5-10mph. The right side pipe also had a very skinny small metal rod-like piece going down the diameter of the pipe a few inches in.

Was the pipe actualy closing and if so, why?

 

some mufflers have a valve inside that closes at low speed to "provide low end torque" and then open at higher speed to be more free-flow...the nissan se-r came with this as well as the 4-cyl. altima

 

neato. thanks

 

what color was the 330Ci and where was it? was it a convertible? i dont know of such a thing on my 330 but I'll check to make sure tomorrow. If it is there maybe it is for a more aggressive tone? It does have a sweet idle - 2k exhaust note.

 

What your refering to is the secondary intake valves that open up at 5 grand to create a shorter airflow path. The valves are a butterfly type, nothing going on in the muffler though.

 

aye, the prelude H series (not sure about F) has the same butterfly valves that open at about 4kish.

thats kinda neat on the muffler though.

 

ha ha ha....



i really should know the answer to this one. but i really dont care. god i love my job.

 

That valve opens and shuts to control backpressure. Its computer controlled.