OK. This has nothing to do with my topic about backpressure. I'm moving onto mufflers and sound. OK... In late February I put a "replica" flowmaster muffler on my 1986 Camaro Z28 (305). It sounded nice, but it wasn't quite noisy enough for me. In late July I decided, it's time for a big change. I took my cat off, gutted it and put it back on. Well... I'm obviously no professional at this and it's hanging a bit lower than it was before, but no big deal. It doesn't scrape... its not that low. So I start her up and ride around a bit and it sounds nice, I love it. It's that sound I've been searching for, but now... I've tightened everything up, loosened things to tighten different things and I cant seem to find a way to keep these annoying noises from happening.

OK... When the engine is completely cold, I start it up and it starts making a humming noise. It sounds like its in the muffler but it sounds like hollow sound coming out the back. No deep rumbles or sound. It sounds nice and heavy around the cat area and into the muffler, but coming out the muffler sounds weird. After a warm up it goes away. I'm really thinking if there is a flap or something inside the muffler it stays stuck against the side until it heats up and then moves. If that doesn't make sense let me know.

Second is that I hear a pumping sound. I know its the air pump pumping air into the cat, but am I supposed to be able to hear that? It sounds like its farting... I don't wanna delete the pump because I think we might have emissions soon. (I can get a cat by then)

Third is the most annoying. It only happens when my car is in a gear. When it's in park it automatically goes away, which makes me assume the flow is through the muffler or something is moving inside something. It sounds like a horn sound actually, a very light horn and its constant. It just keeps going unless I put my foot on the gas or put it in park. None of these problems existed before I gutted my cat.

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Second Section

Now... I've been into the sound clips file and around places, but I still can't find a nice clip of a car with no muffler or cat. I honestly want a tone, but if it still has a bit of a tone and some better sound thats not the kind that attracts cops easily. And I'd like to avoid the pickup truck sound.

I'm leaning toward a muffler delete or a magnaflow muffler. An actual branded flowmaster might be good, but now I'm kinda leaning toward that stainless steel muffler. I've heard SLP is good, but that might be too much work.

Basically, I don't want to go buying another muffler if that is not the problem. I'm off tomorrow so I'm open to suggestions to try messing around with it.

THANK YOU TO ANYONE WHO TAKES THE TIME TO READ THIS WHOLE POST AND UNDERSTAND MY SITUATION TO REPLY TO IT.

 

this is my car with a 305 HO manifolds and y pipe with gutted cat... its loudhttp://s76.photobucket.com/albums/j3...t=100_0033.flv hopefully this helps