JeffNReg

Great forum!! New member (been lurking and reading for a few months). I bought my first Vette back in October. It's an '84, light/dark bronze with 28k miles, and looks every part of it. Beautiful example of an early C4, however, one issue that may be part of the reason for the low miles . At lower RPMs the resonance/drone is unbearable, so bad it makes the dash, etc buzz like crazy. It really ruins the experience. I've looked at the "No Drone" mufflers that Corvette Central offers. Does anyone have these?? I love the way the car sounds once past the drone RPMs, and really don't want it any louder than it is, so these seem like a decent choice. Any other options out there?? Would like to keep stock appearance, not too loud, and zero drone. Quick edit - current mufflers are stock originals. Thanks!!!!

Nowhere Man

what brand of mufflers are on the car now

aminnich

Switch to the stock LT1 mufflers. I bet you can find some 4 sale and cheap right here on the forum.

tazdpc

I had a similar situation with my 89 vette. My son liked the load rumble but it bothered me. I tried to keep the RPMs below 1300 in town. On the open road it was ok. I was looking at taking out the whole interior and but some sound deadening mat in the vehicle. Well I broke down and bought the "No Drone" mufflers from Corvette Central and was very pleased with them. I can not guarantee they will fix your situation, but I am pleased with them.

UNCLEBILL

I have a 1990 Vert and had the Magnaflow catback. After a few years it got louder and the drone got terrible. I also put the Corvette Central "no drone mufflers" on and am very pleased with the sound. I can hear the radio again.
Bill

JeffNReg

Thank you for the replies. Looks like I'll be switching out the stock mufflers for No-drones this spring

96GS#007

Stock mufflers don't drone and are dead quiet. You sure it's not another issue?...like a gutted cat or holes rusted through in the exhaust. Everyone swaps to aftermarket systems because the factory system is so quiet.

c4cruiser

The stock exhaust on the early C4's was very quiet. Look for any gaps at the various connections, especially at the manifolds, the connection at the front Y-pipe, the cat, and the rear y-pipe.

Also check for rust holes where the exhaust pipes enters the mufflers.

If the exhaust system is original to the car, it's reasonable to expect some rust and corrosion after 27 years especially with those low miles. Lack of use allows condensation to build up in the system and rust will start on the inside.

JeffNReg

Hmmmm...never considered anything other than the mufflers. Car does not seem to have exhaust leak, however, is extremely loud (in a good way) even at idle. As mentioned before, I have no problem giving up some of the sound just to get rid of the low RPM drone. How would I check for gutted cat? Does this happen over time or something the previous owner may have done for more sound, etc? Again, thank you.

96GS#007

Post a pic and we can tell you if you have stock or aftermarket mufflers.

A gutted cat would have been something a previous owner would have done for sound and performance (the old cats were restrictive). Only sure way to tell is to pull the exhaust, although you could also tap on it and if it sounds hollow, then it probably is.

George Dickel

It is possible that the previous owner(s) may have replaced the OEM mufflers with an aftermarket set just to get the louder exhaust sound. My first Corvette had after market mufflers that droned something terrible, made the fillings in my teeth vibrate. I believe the brand name was something with the word Turbo in it. The sound outside was great but the drone was just too much.

JeffNReg

I was able to snap some pics last night of the underside. It appears the entire system has a decent amount of rust, however, it doesn't sound like it has any holes or leaks, which usually sound like crap . It sounds great at idle, and once past the droning RPMs.

IAFF alumni

Cats and resonator are still there, but I think the mufflers were replaced by the previous owner.
Yes, they drone.

96GS#007

Stock mufflers. Can't tell if the cat is still in place or not. On the '84-'91 cars, the main cat is located under the center of the car. PO may have replaced it with a test pipe or gutted it as mentioned above. Only way to tell is to climb under there.

One other thing...on the early cars, only one of the muffler outlets was fully functional. Some people punched open the dummy outlet and that will cause drone as well.

cpomavil

I had good luck with "reynolds wrap" and plugged one hole on each mufflers. Car is quiet now.

cpomavil

Stuffed one outlet in each muffler. Quieted down dramatically.

IAFF alumni

Update...

Removed the stock exhaust and the aftermarket Borla mufflers.

Replaced everything with a set of Stainless Works long-tube headers, cat delete, x-pipe, 2.5" pipes and Stainless Works chambered "no-drone" mufflers.

No more drone, and a sweet sound.



FWIW - I've been told that mufflers that have a single inlet and dual outlets (as the Borlas did), will drone.
The SW mufflers are single in, and single out.

YMMV.

0Stainless Works

GLAD WE COULD HELP!
If you get a chance, send us a clip of it at idle and with a little rev too.


for the OP, we have headers for the L98 cars if you are looking to pickup some performance! Our full systems will cover the LT1 C4's from Block to Bumper.

-Jason
Stainless Works Performance Exhaust

ejscarfo

Someone had punched the hole in the stock mufflers on my 85, the drone was terrible. It also helped rot the inside of the muffler out faster I think because when I took them off a lot of debris came out.

I installed the Walker rear y-pipe with crossover tube and and even without mufflers the drone was gone. It was loud, but very bearable. We liked the sound so much we just installed muffler eliminators to carry the exhaust out the back. Best $300 I ever spent!

Jim Rogers

What rear Y-pipe did you use? Was it this one available at Corvette Central? If not, is it similar?

http://www.parts123.com/parts123/yb....Z5Z5Z50000050F

My '85 has some aftermarket mufflers that sound fantastic at idle, but drone like hell between 1110 and 1500 rpm. I'm considering one of these crossover pipes-- but was not sure how well they work.