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Dec 31, 2019 | 08:01 PM

#21

JrRifleCoach

Team Owner

Joined: Sep 2003

Posts: 20,172

Likes: 672

From: Freedom is never more than one generation away from extinction.

St. Jude '03 thru '24

My experience with Rose. Stock 86e, Dumped the OEM mufflers custom fit a set of Borlas to the OEM catback tubes. Replaced the factory CAT with a Magnaflo. Eliminated the front CATs using an 85 exhaust Y pipe. Resulted in a notable drone in the crusing range. Swapped cam, 1:6 rockers, custom tune. The drone was gone. Go Figure

Last edited by JrRifleCoach; Dec 31, 2019 at 08:03 PM.

Dec 31, 2019 | 09:48 PM

#22

Jaye Bass

Thread Starter

Racer

Joined: Sep 2014

Posts: 294

Likes: 119

Quote:

Originally Posted by JrRifleCoach

Cam for sure changes the frequencies of the exhaust pules which is what causes the droning.

Jan 1, 2020 | 10:03 AM

#23

billschroeder5842

Zen Vet Master Level VII

Joined: Mar 2016

Posts: 5,214

Likes: 1,173

From: Southlake, TX

Quote:

Originally Posted by RetroGuy

Hence spend a little extra now, and don't worry about drone again.

Wisdom. I'm reminded of a quote that my grandfather used "Some people enjoy scheming against the inevitable..." Drone elimination is an easy fix.

Jan 4, 2020 | 10:19 AM

#24

RetroGuy

Melting Slicks

Joined: May 2018

Posts: 2,090

Likes: 599

From: Question Government

Obviously drone is mostly an issue for daily drivers or while driving our Vettes on trips, not racing. I consulted the techs at Corsa, and they stated that every one of their models, Cat-back or Axel-back (Sport or Extreme sound) will NOT drone. Apparently they did a lot of R&D to achieve this with our Corvette engines. Their Cat-back systems, which includes an X-pipe, is supposed to have a bit more performance...per the techs. I'll definitely buy a Corsa for my next non-racing Vette and not have to cross my fingers regarding drone.

Jan 4, 2020 | 12:47 PM

#25

bud40oz

Racer

Joined: Feb 2019

Posts: 397

Likes: 29

From: Jackson, mi

alpine.... cure for all drone noises.. lol

but seriously, i hope this new pypes exhaust i just bought doesn't do that, i will be pissed

Last edited by bud40oz; Jan 4, 2020 at 12:48 PM.

Jan 4, 2020 | 01:39 PM

#26

billschroeder5842

Zen Vet Master Level VII

Joined: Mar 2016

Posts: 5,214

Likes: 1,173

From: Southlake, TX

Quote:

Originally Posted by bud40oz

alpine.... cure for all drone noises.. lol

but seriously, i hope this new pypes exhaust i just bought doesn't do that, i will be pissed

Bud, you will have a good idea before your install.... what type of mufflers do you have? If your mufflers follow the "sound absorption" engineering you will have drone at certain rpms. If your have mufflers are " pressure wave cancellation" you will not have drone.

BTW... Corsa and OEM are "pressure wave cancellation"

Jan 4, 2020 | 11:28 PM

#27

aklim

Team Owner

Joined: Jul 2004

Posts: 28,372

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From: Hartford WI

Quote:

Originally Posted by billschroeder5842

BTW... Corsa and OEM are "pressure wave cancellation"

IIRC, there was a article that said Corsa was definitely more efficient than OEM so not sure why it happened since they use the same form of cancellation.

Jan 5, 2020 | 11:27 AM

#28

billschroeder5842

Zen Vet Master Level VII

Joined: Mar 2016

Posts: 5,214

Likes: 1,173

From: Southlake, TX

Quote:

Originally Posted by aklim

IIRC, there was a article that said Corsa was definitely more efficient than OEM so not sure why it happened since they use the same form of cancellation.

Could be.... I'm not sure. I suppose it could be how they "tune" the wave. In ZR1 land, they did a comparison on Corsa vs OEM mufflers and found that the OEM had about 5hp more restriction than the Corsa at WOT. However the Corsa sound different than the OEM probably due to that straight flow through of the muffler exhaust rather than a zig-zag through chambers?