I know this topic has been widely covered and I've done plenty of research, but I'm about to give up. I'm seeing way to many mixed reviews and opinions...

I just recently bought some CNT racing HFC's and a Megan y-pipe and the car sounds fantastic in the sub 3200 RPM range. If I put the pedal to the ground the rasp is just ungodly disgusting. The car literally sounds like a damn honda civic with an ebay exhaust on it.

My headers, mid-pipe and muffler are all OEM. I put these cats and y-pipe on hoping for the performance improvement and a slightly louder/deeper note and I got all of those, but this rasp is practically a deal breaker. I used all new gaskets/hardware that was included with the y-pipe and HFC's.

What gives? How do I rid myself of this horror without getting rid of the setup? Should I try going back to my OEM y-pipe?

Any solid advice would be greatly appreciated because it is honestly embarrassing to drive my car like this...

 

Remove the hfc, or run the hfc with a bigger piping diameter exhaust n rasp gone.Stock exhaust have narrow piping bro.. Get something that has bigger piping like for say new exhaust and done if you don't want a new exhaust just run stock cats & stock exhaust simple as that.

 

Welp clearly I'm not looking to run a stock exhaust if there is a way around the rasp.... What about running a larger diameter mid-pipe? And I know my fair share about exhausts, but I've never shopped for a good mid-pipe or axel back exhaust... Any comments on a good option there?

 

I just installed FI HFCs last night on my OEM exhaust except for a 350z nismo muffler and there is no rasp. More growl from 3K to 5K but I was actually expecting more noise from the HFCs. I am curious whether or not the Cats will make more noise the more they break in.