Added H-pipe. Just moved the drone to different RPMs.

Everything I've had with Flowmasters droaned at some particular RPM. The one I dampened the most was with the glass pack mounted ahead of it. All of mine exited the rear of the cars, no turn downs. I have a slight drone now but I just shift up or down when it gets annoying. Next time I'll be using something other than the flows. It seems to be the common denominator. Also doesn't hurt to make sure your exhaust isn't binding when in operation. They move with the engine torque and when they get hot and the droan can get worse or better as the thing gets hot or cools. I make sure that the whole system is free to move slightly and not get bound against the isolators on the body. With mine, it helped some but the Flowmasters seem to have some inherent tendency to droan anyway.

 

I was had a huge problem with drone on my Toyota truck after replacing a worn out factory muffler with an aftermarket "stock" replacement. (The factory muffler assembly was almost $400 for a base model, 4 cyl., 13 year old truck. Ridiculous!) The cure was to place a resonator in-line before the muffler. No real impact on exhaust flow but dramatic reduction in noise level.

Big engine Mustangs of the 60's and 70's used two glass pack mufflers before both pipes entered a large volume resonator in front of the rear end. This gave good exhaust flow but also quiet sound levels in the car.

 

I have flowmaster on my truck but siamesed (also cats) and no drone.

 

I say either exit them out from under the car (either side exit or go all the way to the rear) or put a resonator in line with each muffler. That is basically the whole purpose of a resonator it to eliminate drone like that.
Believe it or not my Dad's 1972 Maverick Grabber came from the factory with the long round muffler in the stock location back by the gas tank and a resonator up toward the front of the car. Dad eventually got rid of the resonator and he also had a terrible time getting a V8 replacement muffler when his went bad the first time. He couldn't get one anywhere other than the dealer and they kept telling him the V8 mufflers were on back order and wanted to stick a 6 cyl. muffler on it until the V8 mufflers were available. He wouldn't let them do it because he was afraid it would put too much back pressure on the engine and pop a head gasket or something. Little did he know that at the time there probably wasn't hardly any difference in the two mufflers other than a 1/4 to 1/2 inch in the inlet size.

 

seems like the long way around but I have heard alot of people talkin about this

http://forum.grrrr8.net/showthread.php?t=10801&highlight=drone+eliminator

 

But that is so damned UGLY!!!

I just might do it, but I doubt it. UGLY!

I am liking the idea of putting a short glaspak in line prior to the mufflers. Or something. I don't know.

I guess I could cut the superflow44s out completely and put in glasspacks. I would be willing to go back to the glasspack sound rather than flows, but the flows sound so COOL!

 

One other option is a perforated metal cone that goes in the collectors of the header. I saw these advertised as noise reduction for open header/exhaust when complaints arose from the local dragstrip. I think Summit or Jegs sold them. I'm not sure how backpressure is affected, but it might be a lower cost alternative to rebuilding the exh or adding a resonance tube(ugly).

 

Good idea, injected! I have seen those, and wouldn't have to change anything on my current setup!

 

i plan on trying this on my cavalier ive changed mufflers 3 times