Hi guys- I have a 1997 Grand Prix with the supercharged engine. I was under the car over the weekend to remove a leaky and damaged resonator. The exhaust is otherwise from the factory (and surprisingly in decent shape- they must have used good steel!).
I noticed that after the main run of piping toward the back of the car, it splits into two for the dual exhaust. The main piping is 2.25, and it looks like it splits into maybe two 1.75 pipes going toward the muffler. From a volume/velocity standpoint, I'm sure that's fine. But I started wondering whether the actual transition point might be a little restrictive.
I figure that at that point, no matter what, the scavenging effects are pretty much gone because of all the bends to get to the mufflers.
What would happen if that cross pipe were changed to a larger pipe? Either continuing with the 2.25, or even bigger?
What I predict/imagine is that the current setup is causing a bit of a restriction, as the exhaust has to change directions very quickly. It maybe even sets up some weird reflection problems. By increasing the diameter of the pipe, I expect that the direction change becomes less severe, and that the exhaust pulses would be dampened- from a stream of fast pulses to a stream of slower, lower pressure and less dynamic gasses. The result being that the scavenging from the mail line continues as is, or even works better, as the stream has less restrictions to "push against"...
Might change the sound too- I can see where something like that might turn into an echo chamber and make it sound awful, but it could also improve the sound. That would probably be an effect of the resonance of the pipe size, length and material I would use.
I made a basic diagram of what I'm talking about. Top is current, lower is proposed. (The actual system has a lot more bends from the main line to the mufflers, I didn't show them for simplicity.)
Thanks in advance for indulging me in this thought experiment!
I noticed that after the main run of piping toward the back of the car, it splits into two for the dual exhaust. The main piping is 2.25, and it looks like it splits into maybe two 1.75 pipes going toward the muffler. From a volume/velocity standpoint, I'm sure that's fine. But I started wondering whether the actual transition point might be a little restrictive.
I figure that at that point, no matter what, the scavenging effects are pretty much gone because of all the bends to get to the mufflers.
What would happen if that cross pipe were changed to a larger pipe? Either continuing with the 2.25, or even bigger?
What I predict/imagine is that the current setup is causing a bit of a restriction, as the exhaust has to change directions very quickly. It maybe even sets up some weird reflection problems. By increasing the diameter of the pipe, I expect that the direction change becomes less severe, and that the exhaust pulses would be dampened- from a stream of fast pulses to a stream of slower, lower pressure and less dynamic gasses. The result being that the scavenging from the mail line continues as is, or even works better, as the stream has less restrictions to "push against"...
Might change the sound too- I can see where something like that might turn into an echo chamber and make it sound awful, but it could also improve the sound. That would probably be an effect of the resonance of the pipe size, length and material I would use.
I made a basic diagram of what I'm talking about. Top is current, lower is proposed. (The actual system has a lot more bends from the main line to the mufflers, I didn't show them for simplicity.)
Thanks in advance for indulging me in this thought experiment!
