A friend of mine purchased a 3" dual in dual out dynomax. Opened the box yesterday and looked at it. Very poor construction. Looking through one of the holes, the other end is halfway blocked where it was not cut out. He is sending it back and getting a DI/DO magnaflow.

 

I am skeptic about these mufflers also. When they work, they sound good. I have 2 3" mufflers on my Jimmy. I have had it idle but not a chance to open it up yet. I got a great deal though, 2 for 125 shipped through advance auto.

 

Anything new regarding this situation? I've been "assured" that if I get the VTs that they won't make any rattling/clang sound from Dynomax just the other day. But we all know that doesn't mean anything but a waste of my time if I get them for my setup and go through what you are.

 

I have had mine on for about 500 miles. They have a slight clank at cold start up. I am still going to keep them and see if it gets worse. I dont like it because its a new rebuild and when I heard that **** on cold start my butt puckers a little hoping its not internal.

 

I have one of the guaranteed new style mufflers from Dynomax themselves...yes, the "shrank shrank clank" noise at startup is present in their latest and greatest design. The model number is 17957 for those interested.

If the fact that there is an audible metal noise at the exhaust tip is a turn off for you, don't buy this muffler.

If you don't care about what you can't hear in the cab, then this is the muffler for you. I went from a Flowmaster to a Goerlich Xcelerator to a Corsa, then finally the Dynomax VT and the interior drone went from eyeball rattling to none.

 

I got in touch with my former exhaust professor at a college I went to. He actually helped with R&D before Dynomax released the muffler and he said it needed a heavier spring back then. He told me that they don't drone at all and what he does for performance vehicles is that he tack welds the valves open. Even with them fully open like that, they still don't drone at cruise.

I asked why not just get an Ultra Flo and he said that they still have a drone and the VT seems to have more of the roving fiberglass than the Ultra Flo does.

Just a thought for anybody who doesn't mind trying it.

 

other then the clankity clank at start up I might have my flaps welding open. Its a nice mean WOT.

 

the whole welding the valve deal doesnt make sense.

 

Just put mine on last night and ran it around the block, it sounded good at first then it was clanking badly and sounded as if the truck were only running on 4 cylinders.. I pulled the tail pipes and this is what I found!

If you cannot see the picture one muffler has a foot of fiberglass mesh anging out of it?? WTH