I'm totally new to exhaust and all that. Just purchased an '02 F150 5.4. It has an aftermarket exhaust (clamped not welded). I'm happy with the sound level, it's not too lound and not too quiet. The problem is I seem to get a lot of road noise once I hit the hwy. It's kind of a high pitched humming noise that kicks in aroun 50 or 55+ (it comes and goes with the accelerator). Maybe it has nothing to do with exhaust but I suspect it does. Can anyone shed some light?

 

It's called drone or resonance...it comes from vibration in the exhaust system. Some systems have more vibration (creating more drone/resonance) than others creating this affect. Sometimes it can come from a system not being properly installed (loose band clamp on your system). It usually occurs within a certain RPM level and becomes more noticable while in that certain RPM range.

Hope this helps...


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I have the same truck as you. I originally had a flowmaster SI/DO 40 series muffler put on running dual out the back. After I got use to the loudness I decided that it wasnt loud enough for me. I had the flowmaster replaced with a y-pipe. So basically its str8 from cat back. It is loud!! It is loud, but not str8 pipe crackly loud. It has a nice deeeeep rumble. And when you accelerate its loud.

 

The only drone i get is 40mph IF im running up hill and holding 2200 rpms

I have a single dynomax bullet muffler (SISO) dumped.

Pipes that go to rear, or rear corners, tend to resonate more, and louder b.c there is more piping involved.
-Patrick

 

Should probably get that exhaust welded too, clamps have been known to loosen sometimes and you could lose a pipe

 

depends on if you have a tubular clamp, that is like a metal rod bent around it with threads on each end. and a small half collar,
or if you have a "full metal jacket" lol that is like a collar that has two sets of bolts on it maybe like 4-5 inches wide. Most of the LS1 guys have their exuasts clamped on, as long as you got decent hangers, and a decent fit to the headers, you probably could get away with using little to no clamps at all. But it never hurts to keep things secure.

The other nice thing about clamps, if for somereason you need to remove the exaust, it makes it really fast compared to cutting and rewelding it back. Plus the more times you cut it, possible more leaks, and it just wont look as nice!
-Patrick