1bad5.0

Installed the flow master American Thunder si/so kit today and it sounds very good. It comes with 3.5'' piping and a 4'' polished tip, the muffler is a 50 series hd. I recommend this kit for sure. The kit fits 2011-2014 F-150's.

1bad5.0

here is a video i did earlier

1bad5.0

Cold start

brihvac

I thought all American Thunder kits were 40 series mufflers? I am assuming by the sound that you deleted the resonator

1bad5.0

i thought so as well, but when i went on flowmaster's website the american thunder exhaust for our trucks came with the 50 series HD

1bad5.0

and yes the kit i got is a bolt on to the head pipe flange, so the resonator is replaced with a straight pipe.

brihvac

I am afraid of drone and being too loud. I bought a SISO MBRP stainless flange back system from a member here that came with a resonator. Surprisingly it had no drone on the highway and sounded good at idle, but was loud as hell going through the gears. I sold it on Craigslist and put the stock exhaust back on. Just can't find anything I like

1bad5.0

ill be honest there is barely any drone if any heard at highway speeds, it is loud on acceleration and thats the only time you will hear drone once you're geared up and cruising you barely can hear it.

FlowmasterMufflers

American Thunder is a series designation that Flowmaster uses to describe our exhaust systems that produce a moderately aggressive exterior and interior sound level. Because all of Flowmaster's exhaust systems and kits are designed specifically for each vehicle, the muffler or mufflers used in each American Thunder system will vary.