Strange Noise After Down Pipe Install???

[af_maineiac]

Earlier this year, I purchased the Thunderstorm High-Low Down Pipe (w/hi-flow cats) for my '14 SHO. They were installed by a local Ford dealership, and everything seemed to go well with the install. But since then, I've noticed a loud resonating/drone exhaust sound upon acceleration -- but it only occurs in the 3,500-4,000 rpm range. (Best way to describe it is to think of a 4-cylinder import with an obnoxious muffler.) Aside from that, everything sounds fine at idle, low rpm's, and at WOT.

Is this normal, or is this something that I should take back to the Ford dealership to address? (I wasn't sure if anyone else had a similar issue with the down pipes.) The SHO seems to be running perfectly fine otherwise; no DTC codes were found when I checked the MyCalibrator tuner as well. Thanks in advance....

 

[limited02]

I wonder if you are having an exhaust leak? From what I understand, doubling up on gaskets is the way to go.

 

[SHOdded]

Sometimes the downpipes don't line up exactly, and can cause a not-so-secure connection. In addition to double-gasketing, sometimes the connection will work itself loose, so checking it periodically is a good idea also.

 

[Livernois Motorsports]

That is definitely a leak or loose connection. Typically, what happened is that the piping was assembled and tightened as it was installed. You should always slip fit everything together until the fitment is perfect and then tighten everything down from front to back ensuring that your connections are still good as you go. It will usually add some time to your install, but as you can see it can save a TON of headaches down the road!

 

[af_maineiac]

Thanks for the replies! An exhaust leak makes perfect sense.....I'm almost embarrassed that I hadn't thought of that myself.