C4 Mufflers

[DonB]

I'm thinking of replacing the mufflers on my '90. Each side of the exhaust is individual and are straight pipes winding from the manifolds to the mufflers along the tranny and drive shaft tunnel. The existing ones are blown out and getting louder every time I drive it. I still want a bit of "rumble" but the drone is getting deafening. I'd prefer the dual outlet type where both outlets are functional and don't want any restriction. Any reasonable suggestions?

 

[KANE]

Finding the right muffler for your exhaust... can be exhausting. LOL

On a serious note, have you typed in muffler brand names and Corvette to see what they sound like on YouTube? What you may like might be different from what others like.

Corsa, Magnaflow, and Borla are thrown around a lot as popular mufflers for C4s.

Billy Boat, SLP, and others bullet type muffler tend to be a little loud and probably create more of the drone you are talking about.

I'd really encourage you to go to YouTube and listen to the different mufflers. That's about as close to trying one on as you can get.


Sent from my iPhone using Tapatalk

 

[DonB]

Thanks Kane.....Good idea.

 

['96-Z51]

Don't know if I'm too late responding here, but I recently removed Magnaflows from my '96 LT4 because of the annoying drone at highway speeds. I liked the low-speed rumble, but couldn't live with the drone as I do a lot of highway miles on the way to our local sports car roads. I see posts about this drone all over the various forums. I installed replica stock mufflers from Corvette Central (made in North America) and I'm now happy.

 

[GWinter]

Do not install a larger pipe from the cat back. I installed 3 in OD pipes on my 90 from the cat back and without real loud mufflers I have a terrible drone at highway speed . I attribute it to the large pipe. Almost like it creates an echo chamber.

 

[kpic]

I'd really encourage you to go to YouTube and listen to the different mufflers. That's about as close to trying one on as you can get.

Kane hit the nail on the head perfectly. Go to YouTube, crank the volume up and listen.

It boils down simply. Do you enjoy a drone or not? I dislike almost yelling at the wife to have a conversation.

 

[DonB]

Don't know if I'm too late responding here, but I recently removed Magnaflows from my '96 LT4 because of the annoying drone at highway speeds. I liked the low-speed rumble, but couldn't live with the drone as I do a lot of highway miles on the way to our local sports car roads. I see posts about this drone all over the various forums. I installed replica stock mufflers from Corvette Central (made in North America) and I'm now happy.

Those are actually the ones I was leaning towards. Thanks.

 

[DonB]

Kane hit the nail on the head perfectly. Go to YouTube, crank the volume up and listen.

It boils down simply. Do you enjoy a drone or not? I dislike almost yelling at the wife to have a conversation.

The "drone" does get overbearing at times. Like you said, when I have to practically yell at my wife for her to hear me......Although the drone CAN then be blamed instead of my "selective hearing." If you know what I mean. LOL!

 

[kpic]

The "drone" does get overbearing at times. Like you said, when I have to practically yell at my wife for her to hear me......Although the drone CAN then be blamed instead of my "selective hearing." If you know what I mean. LOL!

We went to a restaurant and had to ask the waitress to keep repeating herself.

Selective hearing is a very common disease in married men..

 

[qblue90]

I just installed Corsa on my 90 and could not be happier. No drone at speed and agressive sound when you want it. The seat of the pants dyno registered an increase also. My car was completely stock.

 

[DonB]

Thanks a bunch for that review. I was leaning towards the Corsa.

 

[qblue90]

You won't get 2 working outlets with Corsa. The inboard is a dummy. I was initially bummed about that....until I heard them. One outlet is fine.

 

[DaveP85C4]

Drone is caused by two different, but very close frequencies (pitches) interacting with each other. Two functional outlets on the same muffler, but different lengths from the inlet of the muffler will "speak" at different pitches. Drone. A twin engine aircraft or boat that doesn't have the engines running at exactly the same RPM will drone. If the head pipes are slightly different length, it will drone.

Look up "pipe organ tuning" on youtube. Pipe organs are tuned by sounding the pipe being tuned at the same time as one that has already been tuned. The tech listens for the "beat" of the sound. He taps the pipe's tuning collar to change its length, and the beat slows as it comes closer to tune. When perfectly tuned, there is no beat. My guess is that production exhaust systems are carefully designed and produced to make the system speak with no mismatch in frequency. Aftermarket systems, and muffler-shop solutions probably never even consider what a length mis-match does to the sound.

I feel this "drone" thing is a simple matter of the two mufflers or outlets speaking at different, but very close to each other, frequencies.
I suppose one could fit tuning collars to the outlets, and tune them to match each other with no beat. It works for a pipe organ, it would work for an exhaust system too.

 

[DonB]

Great explanation. Thanks. I'd have never realized what causes the drone sound. But now that you mention it,..It makes sense. Even though I never realized it, my boat has twin engines and if they are close in RPM, but not exact, I get the Drone.