i recently had a flowmaster 4o installed and at first it sounded great but now im getting this helicopter noise in the cab. im guessing its just really bad drone it starting to irritate me. i took it back to the shop who installed it, there was alil exhaust leak. so they fixed it. just curios to see if anyone else had an issue like this with the 40 series muffler

 

Nope. I had mine on my Ford 5.0 for 7 years and it sounded great. Never had an issue with it...

 

its really bad when im cruisin at like 35 40 mph. could it be because of a crappy weld job causing air to leak?

 

I don’t know..

could be a number of things.

 

what should i look for then?

 

Check the whole system visually for leaks or anything out of the ordinary. The 40 is loud, it's going to have a bit of a drone.

 

i knew it was going to have alittle drone when i got it but this is terrible im pretty sure its not supposed to sound like a helicopter blades cutting through the air haha. when this snow in NY goes away ill take a look at the entire system thoroughly.

 

The 40 is loud?

..wow. That’s a first I’ve read that one online.

 

Its all relative. Its the loudest one I have ran, next to strait pipes, but admittedly I haven't run a ton of different mufflers. Isnt it the second loudest one that flowmaster has?

 

I have the Flowmaster Super 10 on my 5.9 Durango. I believe it is the loudest one Flowmaster has.

As for the helicopter drone you are getting sounds to me like a leak somewhere. It would most likely be before the muffler, and seeing that it was recently replaced, I would start there and check every connection towards the engine one at a time.

Hope you find the cause soon!