Sound from a true equal-length Y-pipe
My 2c on sound.
Rasp is generated in the Y-pipe and it can be removed in the catback section by proper selection of resonator and mufflers. Longer and more padding helps but is unlikely to completely remove rasp.
As discussed in another thread (
see here for details) I fabricated a true equal-length Y-pipe + 2.5" catback section. And what I noticed after making the Y-pipe truly equal length from the headers to the cats and from the cats to the Y-merge was that there was no rasp even WITHOUT the catback. Yes, it was loud as ****, and maybe when it is this loud the rasp is masked by the noise.
Putting just the resonator on made everything a lot quieter. But still there was no rasp, though still a little loud.
The only recording I have is with the entire exhaust assembled. Can you tell me if there's any rasp in the following sound clips?
Reving
Driveby
Another contributor to the lack of rasp is the very gradual merge of the two Y-arms directly into the resonator section. I believe this to be conducive to both higher HP and better sound. Btw, if you look at any commercial Y-pipe you'll see that where the two pipes merge they are slightly pointed towards each other. This is counter productive to HP, and I believe also counter productive to good sound, as pulses exiting one pipe will partially try to propagate upstream of the opposing pipe.
Here's two pics of the full exhaust off the car and of the Y-pipe section on the car:
Michael
