Thread: Dronefactory
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Old 09-29-2019, 11:39 AM   #15
aparke4
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Join Date: Sep 2019
Posts: 64
Hi all-

I am chasing this very issue as we speak...

Instead of buying the exhaust mentioned above, I went the easy route and got the second cat bypass pipes first as I heard they can help eliminate the deadly drone. The second cat bypass pipes gave some tone? But overall very very quiet.

After driving for a day drone free but wanting to hear more of that Porsche sound from the 3.2 (2002 S), I had a set of new magnaflow magnapacks in the box from a old jeep build and brought them down to a local exhaust shop to drop the suitcase and throw these in instead. We ended up getting them in and had the two cans meet before exiting out into new aftermarket tips.

The result? LOUD! Dare I say too loud! For the first time in my life, I knew the exhaust was too loud and needed something to be changed. I drove for a few days with one long trip and the drone from 2200rpm to 2900rpm was so loud I got I headache literally within an hour heading to Tahoe and had to get ear plugs.

I went back to the shop and thought I could capture the drone with a set of 12 inch glasspacks in the middle of the second cat bypass pipe... this did not change a thing in dB or drone...

So back to the drawing board... read online a good bit and found the flowmaster Hushpower 2 muffler... they also make the DBX in a 14 inch body which we are going to try in favor of the magnaflow resonators and then move the HP2 mufflers back in place of the 12 inch glasspacks.

I replaced the magnaflows with the HP2 quickly to see if it would cut down on noise which they did but the drone is still there.

Here are my solutions to fixing drone as the tone and sound of the exhaust with the HP2 mufflers is really great- better than the Magnaflow packs for sure.

1. See if DBX 14 mufflers can fit in place of 12 inch HP2's
2. If DBX dont fit, install a second set of HP2 instead of 12 inch resonators = 2 sets of Flowmaster HP2
3. Check drone on highway. If drone is too unbearable, install Car Chemistry baffles OR see if we can install a cross over pipes before mufflers or between both sets to capture more of the killer Hertz.

Only two solutions I found online: Car Chemistry baffles in tail pipes of I found someone that installed two turbo mufflers before tailpipes and that user found that his set up was drone free.

Kinda stinks having to put more restrictions in the exhaust but car chemistry bafflers are like motorcycle baffles and the HP2 mufflers emulate this while maintaining a laminar flow set up.

I am hoping two more HP2's will kill it or the DBX 14's will suffice... its the flat 6 motor and short amount of exaust length that cause the drone. I am experimenting because it will still be lighter than stock and the flowmasters sound pretty dang good.

Will update soon! Heading to shop this coming Wednesday to further experiment.

Glasspacks and HP-2 mufflers did bump up my avg MPG over the last 3k miles. sitting at 22.2 mpg on the dash. No dyno impressions but sound and performance is what I am after.

Sidenote: some people have mentioned using a WRX muffler. The muffler design has two side inputs and a center out for the tips... just another idea as this design is closer than anything to the stock muffler design.
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