Exhaust REALLY LOUD! Help??

[dssking]

I just purchased an 88 Coupe here in Toronto. Car is completely stock, with the exception of Flowmaster mufflers. The resonance it produces is so loud that I cannot hear the radio, which will eventually be replaced once I can actually hear it. So, Mid-America sells a factory replacement kit (mufflers only) for $199. Does anyone know if it's a decent system?

Someone here mentioned that resonance could be due to the installation. Is this true? Is there anything I can do to the currentl system to quiet it down?

Just starting to learn about Corvettes. I've been a Mustang 5.0 man for years.

DSSKing

 

[vader86]

Only ways i know of to reduce resonance is to extend the pipes past the bumper, or welding in a crossover pipe. I would try the extensions.

Flowmaster is like that though, and I bet the mufflers in MAD that you refer to are just as bad.

 

[SurfnSun]

resonance and the C4 are the never ending battle. I had borlas that stuck out past the bumper and they were so loud it ruined the car. If you really want quiet go back to stock or have a corsa system modified and put in place.

 

[Corvette Streetracer]

I have a 96 LT-1 running a touch under 390hp. I use the MAD muffler eliminators. They caused system to resonate. I extended pipes 3" past rear bumper...Problem solved. Everyone who hears it says it sounds sweet throughout the RPM band. It howles like a b*tch at 120+ and I love it!!

 

[dssking]

Extending just the 4 tips 3 inchs past the rear bumper?
Hmm..... That's a cheaper way to test rather than new mufflers that will no doubt starve the engine.............

 

[Rogue]

If you look carefully at your Mid-America catalog (also Ecklers), you'll see a Y-Pipe with a crossover pipe made by Walker Dynomax. This is the only Y-Pipe I've seen with this crossover pipe for the C4. According to both catalogs, this Y-pipe w/crossover pipe "eliminates" the resonance. You can buy the Y-Pipe by itself or get it with matching Dynomax mufflers.

I don't know if this product will indeed eliminate interior resonance as I do NOT have this on my C4. But for the price they're selling it for, it's worth a try.

It seems the only other way to eliminate interior resonance from an aftermarket higher flowing mufflers on a C4 is to either buy the Corsa exhaust ($900), or replace the aftermarket mufflers with the stock mufflers (with the single functioning exhaust tips in EACH muffler).

 

[oldace84]

I use the flowmaster mufflers...and don't see all these problems.....sounds great....runs great...
I'm a happy camper!!!!!!!!!!!!!
Soooooooooooooooooooo...............
tony

 

[Edmond]

I use the flowmaster mufflers...and don't see all these problems.....sounds great....runs great...
I'm a happy camper!!!!!!!!!!!!!
Soooooooooooooooooooo...............
tony

:BOW Same story here Brother!

 

[RedRagTop]

I have the Flowmasters and like the mild burble I get, certainly not too noisy even in slow mode with top down...

 

[Hotred94]

When I bought my 94, it came with a Flowmaster 40--extremely loud! I thought about replacing it but the cost was too high; and besides, it does sound great, just too loud. So I decided to insulate as much as I could before I got too drastic and ripped it out.

I put two insulating layers on the rear floor, sides, and back. Then I put one layer on the outside underneath and on the sides. But for the outside rear, I got one of those foam shop floor pads, they're about a half inch thick made of dense gray foam (you buy four in a package and it costs $7.50 at Sams). I cut one to fit the size of the panel and pressed it in between the panel and the gas tank. It was a tight fit but it worked out perfect. Then I lined the little boxes in the rear floor (don't forget to insulate inbetween the boxes under the hatch cover).

Now the muffler noise is much improved on the inside, but still rumbles on the outside. Eventually I plan on putting some tips on that will extend further out past the end of the bumper. That will help even more.

 

[Corvette Streetracer]

There will be a big drop in noise when you move those exhaust tips out a little. Dont worry ... you'll get used to the way it looks

 

[LT4man]

I have a 96 LT4. I removed stock mufflers and am using the MAD muffler eliminator pipes. With the stock GM resonator assy. still in place, I have a great sound outside the car. It sounds like a built small block Chevy! Inside, I have NO resonance at all. The pipes cost me $129.00 plus $70 for installation. Sometimes the cheapest solution is the BEST! You can have your $500 - $1,300 exhaust systems. I get compliments wherever I go. Plus the rear of the car is cleaner because there are not any mufflers hanging. I also have the spare tire delete option, so there is no spare tire hanging either.

 

[dssking]

Well, I ordered the Quiet Flow mufflers for $199 USD from Mid-America and had them installed in place of the FlowMaster mufflers. Noise is cut in half, slight resonance which is now livable, but I lost some bottom end power. Not a huge deal though....
So now, it's time to gain back some bottom end torque...suggestions?

Thanks for all of your suggestions.

 

[KouKou]

dssking,

did you end up solving the problem?

What's next on the list of upgrades?

I am from markham also...If you want we could get together some day and trade ideas...

 

[KouKou]

dssking,

did you end up solving the problem?

What's next on the list of upgrades?

I am from markham also...If you want we could get together some day and trade ideas...

 

[diesel1456]

excessive interior noise

I happen to agree with LT4 i have an 89 i took off the stock mufflers and put in the bypass pipes and it runs great sounds great and was cheap. I also have a full body kit and my exhaust sticks out the back a good 4-5 in ( c-pic )
Rich

 

[grapeknutz]

I have dyno max super turbos on my 92 and a Dr gas X cross over and I do not have any resonance!

 

[KouKou]

well, so far the worst system for resonation IMO is the 3" B&B Tri-Flo. The car sounds mean but gives me a headache driving @ 1500-2500 RPM. I love the sound but only if used on a car driven occasionaly and not a daily driver like mine.