Why do C4s drone?
08-17-2018, 05:43 PM
#42
Burning Brakes
Sorry, I know this topic has been beaten to death. I don't want to start a long thread about which exhaust combinations drone, how Corsa is the only way to go, how Flowmasters are terrible etc., etc. I'm more curious in the cause of C4 drone. I have extensive wheel time in C2 Corvettes and they don't drone despite having a glass enclosure behind the driver. I've driven C3s and most don't drone. What is it about the C4 that causes drone? All the earlier generations mentioned have mufflers in similar locations which rules that out. I'm aware of exactly what drone is, but specific causes in the C4 puzzle me (especially since it doesn't appear to affect earlier cars. Thoughts about the science behind it welcome, not looking for a brand shootout. Thanks for any insight into this.
08-17-2018, 07:06 PM
#43
Burning Brakes
My opinion is Camshaft Duration causes most of what you hear and is the reason that C2s and C3s don't have it. Lift on the lobes is relatively similar across many of the engines, but the durations were much shorter starting with the C4s to improve throttle response and increase low end torque. My C4 does not drone, but my cam isn't stock either.
08-17-2018, 07:26 PM
#44
Burning Brakes
Well... I'm not sure how else to say it.
The OP makes the point that C2s and C3s he has been in didn't drone. There are lots of factors that can come into play, one most definitely being that those C2s and C3s that he drove didn't lope along at 70 MPH at 1200 RPMs, therefore it's hard to make a direct comparison unless you compare exhaust noise at RPMs. My only point of reference (other than I have driven several C2s and C3s as well that didn't drone at cruise speed) is that the C4s that I have driven, that have performance cams and performance exhaust systems don't drone at cruise speeds. There are lots of factors that come into play with respect to camshaft differences, so I'm only comparing the factory cams with performance exhaust.
The OP makes the point that C2s and C3s he has been in didn't drone. There are lots of factors that can come into play, one most definitely being that those C2s and C3s that he drove didn't lope along at 70 MPH at 1200 RPMs, therefore it's hard to make a direct comparison unless you compare exhaust noise at RPMs. My only point of reference (other than I have driven several C2s and C3s as well that didn't drone at cruise speed) is that the C4s that I have driven, that have performance cams and performance exhaust systems don't drone at cruise speeds. There are lots of factors that come into play with respect to camshaft differences, so I'm only comparing the factory cams with performance exhaust.
08-17-2018, 07:41 PM
#45
Burning Brakes
Well... I'm not sure how else to say it.
The OP makes the point that C2s and C3s he has been in didn't drone. There are lots of factors that can come into play, one most definitely being that those C2s and C3s that he drove didn't lope along at 70 MPH at 1200 RPMs, therefore it's hard to make a direct comparison unless you compare exhaust noise at RPMs. My only point of reference (other than I have driven several C2s and C3s as well that didn't drone at cruise speed) is that the C4s that I have driven, that have performance cams and performance exhaust systems don't drone at cruise speeds. There are lots of factors that come into play with respect to camshaft differences, so I'm only comparing the factory cams with performance exhaust.
The OP makes the point that C2s and C3s he has been in didn't drone. There are lots of factors that can come into play, one most definitely being that those C2s and C3s that he drove didn't lope along at 70 MPH at 1200 RPMs, therefore it's hard to make a direct comparison unless you compare exhaust noise at RPMs. My only point of reference (other than I have driven several C2s and C3s as well that didn't drone at cruise speed) is that the C4s that I have driven, that have performance cams and performance exhaust systems don't drone at cruise speeds. There are lots of factors that come into play with respect to camshaft differences, so I'm only comparing the factory cams with performance exhaust.
08-19-2018, 01:20 PM
#47
Burning Brakes
08-25-2018, 12:17 PM
#49
Burning Brakes
Tremendously = Took it from a bad drone at certain R's to a much more muffled sound. Does it still drone? Some, but it's definitely livable.
Here is the material I used. Applied very nicely.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
After I removed the carpet and pad, I tapped on the floor pan. It's like a hard plastic bass drum. I can see why there's some sound issues.
Here is the material I used. Applied very nicely.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
After I removed the carpet and pad, I tapped on the floor pan. It's like a hard plastic bass drum. I can see why there's some sound issues.
So I purchased this kit and in facts it coming today. But when I started to pull up my carpet I noticed it already has sound deadening material. Is this dynamat type stuff going to help? And I suspect its all glued down.. dont think its wise to try and remove.. did you remove yours?
08-25-2018, 12:22 PM
#50
Team Owner
That old jute is junk today. It provides very little sound absorbsion and if it gets wet it retains moisture. It should pull right out. Only a couple spots in my 87 had very light adhesive on it
08-25-2018, 12:28 PM
#51
Burning Brakes
08-25-2018, 12:32 PM
#52
Team Owner
Tons of them. All the rear trim has to come out. There are a couple hidden discs under the rear hatch latch trim too the carpet goes up and over a couple of bolts.
Last edited by scorp508; 08-28-2018 at 10:11 AM.
08-25-2018, 01:02 PM
#53
Team Owner
Member Since: Oct 2004
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St. Jude Donor '05
Short exhaust system youre sitting right on top of.
as said the interior acts like a speaker box. Glass amplifies sound, too.
Dynamat wont make a car quiet...it may tone down a certain frequency some but dont get your hopes up
Get a quieter muffler thats where the solution is. If a stock type is too loud then a sports car isnt for you.
See guys complaining their stock C6 is too loud, not sure what people expect!?
as said the interior acts like a speaker box. Glass amplifies sound, too.
Dynamat wont make a car quiet...it may tone down a certain frequency some but dont get your hopes up
Get a quieter muffler thats where the solution is. If a stock type is too loud then a sports car isnt for you.
See guys complaining their stock C6 is too loud, not sure what people expect!?
08-25-2018, 01:05 PM
#54
Burning Brakes
Short exhaust system youre sitting right on top of.
as said the interior acts like a speaker box. Glass amplifies sound, too.
Dynamat wont make a car quiet...it may tone down a certain frequency some but dont get your hopes up
Get a quieter muffler thats where the solution is. If a stock type is too loud then a sports car isnt for you.
See guys complaining their stock C6 is too loud, not sure what people expect!?
as said the interior acts like a speaker box. Glass amplifies sound, too.
Dynamat wont make a car quiet...it may tone down a certain frequency some but dont get your hopes up
Get a quieter muffler thats where the solution is. If a stock type is too loud then a sports car isnt for you.
See guys complaining their stock C6 is too loud, not sure what people expect!?
Last edited by barchetta1; 08-25-2018 at 01:06 PM.
08-26-2018, 05:22 PM
#58
Team Owner
Pro Mechanic
^^Right? It makes way more sense for every one to search for it. He's using his DtSense. 
08-26-2018, 05:39 PM
#59
Safety Car
My apologies, I was pretty tired when I posted.
https://www.corvetteforum.com/forums...xperience.html
https://www.corvetteforum.com/forums...xperience.html
