What changes in sound from changing to a hi-flow cat?

[mid_life_crisis]

I have very little experience with small engine exhaust systems. I'm looking at replacing parts of mine. Specifically the secondary cat gets replaced with a hi-flow unit and everything after gets replaced also. The problem is that the only guy in the area with the same exhaust did not replace his cat.
If I listen to his system, other than the obvious volume level differences, what other differences should I expect from the different cat?
Will "drone" level change?
What about "rasp", although I freely admit I'm not 100% clear on exactly what this sound is in an exhaust?

[steve99]

Originally Posted by mid_life_crisis

I have very little experience with small engine exhaust systems. I'm looking at replacing parts of mine. Specifically the secondary cat gets replaced with a hi-flow unit and everything after gets replaced also. The problem is that the only guy in the area with the same exhaust did not replace his cat.
If I listen to his system, other than the obvious volume level differences, what other differences should I expect from the different cat?
Will "drone" level change?
What about "rasp", although I freely admit I'm not 100% clear on exactly what this sound is in an exhaust?

Guy came over with a perrin catback and high flow cat. Perrin catbacks usually nice fairly deep tone and not too loud, but with the high flow main cat it was very loud and more i suppose what you would call raaspy and ricy, dont know about drone as i did not get in the car just heard him come and go, he had standard headers.
If you dont want drone keep resonator or get resonated catback
Probably be ok if you keep standard muffler or have a very quiet replacement, uless you like loud.

[mid_life_crisis]

Can someone point me to a sound clip that is a good example of a raspy exhaust? Drone is easy: anyone who's been stuck behind a teenager in a Civic knows what that sound is, but I still need help with rasp.

[BlueDubbinTDI]

Louder cold start and a slightly louder more uncontrolled and raspy exhaust note. It's good more power but not for sound usually

[ATL BRZ]

Originally Posted by mid_life_crisis

Can someone point me to a sound clip that is a good example of a raspy exhaust? Drone is easy: anyone who's been stuck behind a teenager in a Civic knows what that sound is, but I still need help with rasp.

Raspy example, catless equal length header, 3" headerback, high flow catted and resonated front pipe, resonated mid pipe, muffled axleback: http://www.ft86club.com/forums/showt...43#post1661243

Non raspy example. Catless unequal length header, 2.5" OP, 2.5" high flow catted and resonated front pipe, stock resonated mid pipe and a muffled axleback: http://www.ft86club.com/forums/showt...84#post1728684

IMHO the key to avoiding obnoxious rasp and volume levels while n/a is keeping the piping diameter at a maximum of 2.5" and having a well resonated front pipe and mid pipe along with sizable muffler(s) in the axleback portion..

My new 2.5" high flow catted and resonated front pipe has added noticeable depth to the exhaust note and it's a little bit louder but there is no drone or rasp anywhere.