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About three weeks ago, my midpipe cracked mostly open before the main cat in the flex pipe while driving up a friends driveway. It had been slightly cracked before but I didn't get it fixed because it wasn't a major problem. The sound was phenomenal, with my only complaints while driving it for two weeks waiting for my high flow cat/midpipe from NPG to arrive being that it was too loud (although I went to church with my mom in it and she didn't mind too much), it vibrated the cabin too much since it was right under the center tunnel, and it had a horrible and sometimes embarrassing rasp because it was before the resonator.
After fixing it a few days ago, it was simply too quiet (Camry quiet), and I missed the sound. I didn't want it to be too loud, just to have an enjoyable tone, and to be able to hear the pops and snaps and burbles clearly like I did with the pipe cracked. So I asked my friend with an angle grinder to cut open two sections on the bottom of the factory mufflers. The whole job took about 30 minutes including clean up and the metal is not thick. Basically, we started by cutting the bottom section just before where the tips would exit ("front" of muffler), then tested how loud it was. We decided to also cut the rear section right where the drainage hole is in the mufflers after that.
Doing this, we saw the open ends of a separate pipe (the baffle pipe), which means that there are at least three chambers in our muffler. The pipe enters from the Y pipe, goes in to the middle of the muffler, flows either through perforations or more unknown baffles to the other pipe sitting in there, which enters to separate chambers in the front and rear of the muffler, and returns back through the main chamber and out the main outlet in stock configuration.
With the two end baffle chambers open, it has a sound comparable to the Tanabe Medallion axle back I would say. Around town, it's very quiet, and at certain rpms it reaches a frequency where it's almost silent (some sound waves completely canceling each other out then), and at other throttle positions, it's very loud, boomy, and resonant. It has a lovely melodic rumble, and is quiet in the cabin around town. You can also hear deep booming pops when coasting and decelerating at low rpms. Unfortunately, it's horrible horrible drone on the highway. I think most of this is from the rear baffle section being open since it's closer to under the rear seats, and accelerating on the highway at or near 3k rpm with the throttle open makes the whole cabin almost but not quite unbearable.
My plan is to weld the rear baffle pipe shut and weld the floor of the muffler back shut and see how that helps. Hopefully it brings back some of the rawness and pops, and will force flow back through the main chamber and other chamber, preventing drone.
I'll report what happens if it gets done. Hopefully I can get some photos and a video on here too.
After fixing it a few days ago, it was simply too quiet (Camry quiet), and I missed the sound. I didn't want it to be too loud, just to have an enjoyable tone, and to be able to hear the pops and snaps and burbles clearly like I did with the pipe cracked. So I asked my friend with an angle grinder to cut open two sections on the bottom of the factory mufflers. The whole job took about 30 minutes including clean up and the metal is not thick. Basically, we started by cutting the bottom section just before where the tips would exit ("front" of muffler), then tested how loud it was. We decided to also cut the rear section right where the drainage hole is in the mufflers after that.
Doing this, we saw the open ends of a separate pipe (the baffle pipe), which means that there are at least three chambers in our muffler. The pipe enters from the Y pipe, goes in to the middle of the muffler, flows either through perforations or more unknown baffles to the other pipe sitting in there, which enters to separate chambers in the front and rear of the muffler, and returns back through the main chamber and out the main outlet in stock configuration.
With the two end baffle chambers open, it has a sound comparable to the Tanabe Medallion axle back I would say. Around town, it's very quiet, and at certain rpms it reaches a frequency where it's almost silent (some sound waves completely canceling each other out then), and at other throttle positions, it's very loud, boomy, and resonant. It has a lovely melodic rumble, and is quiet in the cabin around town. You can also hear deep booming pops when coasting and decelerating at low rpms. Unfortunately, it's horrible horrible drone on the highway. I think most of this is from the rear baffle section being open since it's closer to under the rear seats, and accelerating on the highway at or near 3k rpm with the throttle open makes the whole cabin almost but not quite unbearable.
My plan is to weld the rear baffle pipe shut and weld the floor of the muffler back shut and see how that helps. Hopefully it brings back some of the rawness and pops, and will force flow back through the main chamber and other chamber, preventing drone.
I'll report what happens if it gets done. Hopefully I can get some photos and a video on here too.
