Exhaust Drone

Discussion on fuel delivery & intake/exhaust tech & mods.
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GTObert
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Exhaust Drone

Post by GTObert »

So I just picked up my car after having my exhaust installed. I got Stainless Works SS catless headers and the mufflers from their SS kit. I had to have an X pipe and all the tubing from headers to mufflers custom fabbed. Needless to say this thing now sounds like the beast it was always meant to be, but now I have a pretty intense bass drone in the cabin. I read something here about dynamat before and now I'm staring to think it may have been to solve this issue. Has anyone done this and how did it work for you?
2011 9C1
2005 GTO
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greasychevy
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Re: Exhaust Drone

Post by greasychevy »

Ive heard good things about dynamat, never tried it. Do you have DOD turned off? Ive found my drone is worst at about 69mph in OD. I try to avoid that rpm band.... Its so bad it blurs my vision.
2011 9c1 Hugo Blue
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GTObert
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Re: Exhaust Drone

Post by GTObert »

I do have dod turned off. This isn't a drone from that, it's just really loud, deep noise from the exhaust.
2011 9C1
2005 GTO
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GTObert
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Re: Exhaust Drone

Post by GTObert »

So after a little reading I seems I need some J pipes. I have seen that lots of guys here have the solo axel back kit. Does that include a J pipe and if so how long is it? I am not sure if I'll be able to fit a pair of these in my system but I want to at least look into it.
2011 9C1
2005 GTO
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storm9c1
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Re: Exhaust Drone

Post by storm9c1 »

Another thing to try is to extend the tips past the end of the bumper. That's an old muscle car trick. Any tips that exit under the bumper (but not beyond it) would drone REALLY loud. So get some longer straight sections and make the exit about 1" longer than the bumper -- at least for testing -- and if that works, design something less ghetto.
Tom (AKA: Storm)
2011 Caprice 9C3: L77, 8K miles, first-owner, purchased July 2011.
1995 Caprice 9C1: LT1, 178K miles, summer car.
1995 Impala SS: LT1, 21K miles.
1995 Caprice Wagon: LT1, 62K miles.
1995 Caprice Wagon: LT1, 128K miles. Rust In Pieces
1994 Caprice 9C1: LT1, beater winter car.
1969 Chevy C30: 383ci stroker, 4L80E, rollback car hauler.
1972 Chrysler Newport: 400ci big block, survivor 27K miles, 2-door hardtop.
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Pursuit
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Re: Exhaust Drone

Post by Pursuit »

In talking with Chris from Stainless works during development of the SS system, the muffler design went through quite a few design changes. The addition of the "J-tube" within the muffler did happen. The J-tube design is also used in the factory mufflers of the Camaros, Caprices and SS'. That design deals with the DoD drone. With the lack of catalytic converters to "laminate" or straighten out the exhaust pulse, the pulse has free range within your system. I would agree with extending the exhaust pipe past the bumper. I have done that before also. What rpm are you seeing the drone?

Maurice
Maurice Sheil

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2011 Caprice Phantom Black 9C3
2012 Impala 9C1
1995 9C1 Caprice
1996 GMC Sierra C1500
1996 Chevrolet K2500 Extended Cab, long box, 454, 91,000 rust free miles
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toyguy5538
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Re: Exhaust Drone

Post by toyguy5538 »

There is a ton of information about the exhaust drone with aftermarket exhaust systems on the Pontiac G8 board. There are several threads under the exhaust heading in the forum. Some explain the engineering of why it happens and how to correct it. It seems the J-tube is what is missing in the aftermarket systems and what has to be added to get rid of the drone.
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GTObert
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Re: Exhaust Drone

Post by GTObert »

The drone seems to be the worst at 2000 rpm. Since I am using the Stainless Works SS mufflers, I'm not sure how effective they are at eliminating this noise. The tailpipes are exactly even with the bumper and that's where they're staying as they had to be extended and welded in place to begin with. I spoke with my exhaust guy and he thinks the J pipe should be no problem; they have previous experience.
2011 9C1
2005 GTO
Pursuit
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Re: Exhaust Drone

Post by Pursuit »

Is the DoD active when you are hearing the drone at 2000 rpm?

Maurice
Maurice Sheil

mhsheil@gmail.com

2011 Caprice Phantom Black 9C3
2012 Impala 9C1
1995 9C1 Caprice
1996 GMC Sierra C1500
1996 Chevrolet K2500 Extended Cab, long box, 454, 91,000 rust free miles
1974 SJ Grand Prix 455 well optioned with factory moon roof
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GTObert
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Re: Exhaust Drone

Post by GTObert »

Yeah I think I forgot to mention I don't have dod.
2011 9C1
2005 GTO
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