[wang970305]

I know corsa advertises their exhaust as zero drone but somehow I have some drone at 2k rpm with corsa extreme axle back on my 21 SS and have drone at 2.2k on the catback. When I had Borla atak axle back, it wasn’t that bad. Somehow corsa is louder and gives me more drone. Not sure if this is caused by the sec cats delete? Attached a picture before I put on the mid pipe, the guy weld a 2.5 inch pipe to eliminate the sec cats.

Anybody has this experience as well?

[wang970305]

If I cut off the 2.5 pipe and put on a 3” inch, would that help? A semi muffler shop said 2.5 is still bigger than the primary cats pipe so it doesn’t affect anything

[WhiteMale]

Corsa isn't known to drone that I can recall, it's really popular on the forum. Most people don't know what drone really is though compared to tone and volume that is unpleasant to them. Either/or, sure, the 2d cat delete could be what made the sound unpleasant for you.

[wang970305]

Originally Posted by WhiteMale

Corsa isn't known to drone that I can recall, it's really popular on the forum. Most people don't know what drone really is though compared to tone and volume that is unpleasant to them. Either/or, sure, the 2d cat delete could be what made the sound unpleasant for you.

Well is there a solution for this?

[adamjwilson]

Originally Posted by wang970305

Well is there a solution for this?

I don't have any drone on my Corsa NPP axle back exhaust. Can you post a video of what you are hearing? Maybe that will help the forum here to assist you?

[WhiteMale]

Take off the Corsa that you don't like?

[wang970305]

Originally Posted by WhiteMale

Take off the Corsa that you don't like?

ok whitemale, it does not help solve the problem

[adamjwilson]

Video with sound please if you need assistance

[SomeGeoffGuy]

From what I know about them they tune the mufflers to the stock system. So if you make a lot of changes, it might shift out of the muffler's tuning frequency.

I would give them a call and ask them - I think they have a tech support line. Maybe they can help?

-Geoff

[ctrlz]

Originally Posted by SomeGeoffGuy

From what I know about them they tune the mufflers to the stock system. So if you make a lot of changes, it might shift out of the muffler's tuning frequency.

I would give them a call and ask them - I think they have a tech support line. Maybe they can help?

-Geoff

Well this sounds highly likely.
OP went from an axle-back to a cat-back, but also deleted the secondary cats. This is definitely going to change the frequencies of the system. I suspect the cat-back is intended to work with the secondary cats in place.

The pipe diameter isn't really what's important here, although that may alter the frequency a bit. The baffles are now gone and the effective length of the pipe where gases/pressure can oscillate has changed.

[WhiteMale]

what about some bullet style resonators in the mid pipe area?

[WhiteMale]

Originally Posted by wang970305

ok whitemale, it does not help solve the problem

It does. You liked the Borla. Problem solved rather easily I think. Corsa was always too aggressive for my tastes in it's tone and volume. 2d cat deletes usually result in a raspy tone that few like but they like to brag that they did it

[wang970305]

https://youtube.com/shorts/ww4nCBQ_s0g?feature=share

Phone recording can’t do the Justice, I tried to keep the rpm at 2.2k and u can hear a low tone sound but it’s actually drone and at the last second it is gone because it went above 2.2k

[adamjwilson]

Wang- I don't hear any drone?? NPP exhaust? In Sport mode?
Heck… maybe I am tone deaf!