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Discussion Starter · #1 ·
Hello
I have a Fiero with a Series II 3800 SC motor, headers, catalytic and dual mufflers

My exhaust sounds fine at idle and when revving at a standstill, but at certain speeds, it has a really annoying "drone" sound. I have heard this same complaint from many others with the same car/engine combo

Is this a 3800 "thing" , crappy sounding exhaust? The stock 60 deg V6 sounded way better on the highway. I wonder if there is anything that can be done?
 

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When you open up the flow on a V6 exhaust with offset banks (transverse mounting), you'll get this effect. That's why ZZP finally released an Equalizer crossover/downpipe that collects evenly in the center of the banks like most turbo systems do. Another factor is how much more open we tend to make exhausts on the 3800SC's to flow the extra air, and in this configuration, it's not the best sounding.

It's hard to avoid without changing the layout... I built the exhaust below in 2009 for a guy's X-P cam'd/intercooled Fiero with SSAC headers (SLP eBay clones), and it was the best sounding non-equal length one I've heard, but still had that note. (shortened trunk, Magnaflow F-body muffler)

Bicycle part Nickel Household hardware Composite material Tin
 

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Discussion Starter · #3 · (Edited)
It was suggested that I look into Quarter Wave Resonator in place of my catalytic converter, so I may give this a try. I really don't like removing catalytic and increasing pollution unnecessarily, so hopefully there is another solution. Will post here if the resonator helps, though the length of the resonator may not fit into the tight Fiero space....
 

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I agree the 3100 in the Grand Am I had years ago (which was a close descendent of your 2.8) sounded good for a v6. First thing is to check for any leaks and to see if any part of the exhaust is contacting on the body. The zzp powerlogs with equalizer if it fits would be the best option, although the most expensive. I know there isn't much room to work with in there. Maybe a set of resonated exhaust tips would help. Even if you find a set of the factory 97-03 GP rectangle tips or Bonneville oval tips they project the sound like a megaphone, but strangely the acoustics of it reduce interior drone. I used a factory GP tip on my Grand Am when I did a muffler delete on my last exhaust setup on that car. It was loud, but surprisingly it had almost no drone. I can't speak for it on the GP.... different engine. On my GP I have a full slp exhaust headers back. At one point I tried magnaflow oval resonated tips with it. Muffled the sound a decent amount, but decided I wanted the look of '04 SPO tips more. Eventually put in a loudmouth II as a resonator which helped tone down some of the raspyness and killed most of the drone.

Here's two comparison videos of my exhaust from way back when before I added the loudmouth resonator just to show the difference in sound between the magnaflow resonated & spo tips. Yes I did fix the spo tips sticking out a mile from my bumper.
resonated tips
non-resonated tips
 
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