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GMMG drone reduction

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Old Sep 19, 2009 | 12:07 PM
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Default GMMG drone reduction

Has anyone every used one of these? Classic Chambered 30-RES 3" Resonator. I have a GMMG exhaust and I would like to cut the drone.

Thanks Ed
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Old Sep 19, 2009 | 01:08 PM
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I would just use a dynomax bullet as a resonator in the I pipe. That or buy a dynomat trunk kit and line the trunk pannels with dynomat to kill the drone.
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Old Sep 19, 2009 | 10:02 PM
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I put a powerstick in my I pipe.. Killed about 99% of my rasp
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Old Sep 29, 2009 | 12:10 PM
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Originally Posted by BRD-PREY
Has anyone every used one of these? Classic Chambered 30-RES 3" Resonator. I have a GMMG exhaust and I would like to cut the drone.

Thanks Ed
If you are going to install it in the midpipe, you could use a 20" bodied resonator, possibly a little longer. Basically, I'd build you a Cobrapack with packing & that would absorb a nice chunk of decibels. A 3" version has a 3" core & a 4" OD body.

Thanks, -Eric
www.classicchambered.com
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Old Sep 30, 2009 | 12:35 PM
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I installed an additional GMMG muffler in the I pipe. It made a noticeable difference while cruising. You can easily have conversation in the car now and the exhaust doesn't overpower the radio anymore. I also have zero rasp.

I wanted to keep my exhaust 100% GMMG besides my headers.
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Old Sep 30, 2009 | 06:11 PM
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Originally Posted by JScamaro
I installed an additional GMMG muffler in the I pipe. It made a noticeable difference while cruising. You can easily have conversation in the car now and the exhaust doesn't overpower the radio anymore. I also have zero rasp.

I wanted to keep my exhaust 100% GMMG besides my headers.
And y pipe
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Old Oct 2, 2009 | 07:04 AM
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Thanks for the advice, here's were I'm at; The headers install is complete. I had a crappie looking cutout pipe in my intermediate pipe. So based on the audio clips it was obvious to me that just my GMMG exhaust was going to be too loud. So after I got the Y-Pipe where I needed it, I picked up a dynomax bullet with an 18" muffler section from the local advance. I was able to get the car back on the road. It sounds really great but its still too loud for a daily driver. Don't get me wrong most people would be happy, my wife even doesn't complain but I put 600 miles a day on the car a week. If it was just a fun car I wouldn't change it! If your not on the throttle its actually quieter and BEST of all no Drone! I do have a rasp that kicks in at about 2300 rpm gone by 2500 rpm if the throttle is more than half way open. So I called Eric at classic chambered and had him send me 2 12" resonators. I'm going to weld them in between the tips and the first curve. I hope this will tone it down just a bit.
On a side note, to my surprise Patrick G. who spec'd my cam, when asking me about my exhaust mentioned that the GMMG is not as free flowing as I thought. That on the LS3 417 I might find it to be too restrictive. That surprised me but after talking to Eric as classic chambered he told me why and said I could cutout the 2 GMMG chambers and put 2 larger powersticks in. Sounds like a good idea, I will probably do this in the future.

Does anyone no where to get a good turnout for over the axle to go from 3" to 2) 2.5

Ed

PS I definitely notice more horsepower and a better throttle response. I'm putting the wideband O2 in now to start tuning.
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Old Oct 2, 2009 | 07:28 AM
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Originally Posted by BRD-PREY
Patrick G. mentioned that the GMMG is not as free flowing as I thought. That surprised me but after talking to Eric as classic chambered he told me why and said I could cutout the 2 GMMG chambers and put 2 larger powersticks in.
What was Eric's explanation as to why the GMMG is restrictive? Is it that the diameter of the GMMG chambers is too small?
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Old Oct 2, 2009 | 03:53 PM
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I want to know that answer also.
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Old Oct 2, 2009 | 09:42 PM
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Yea, exactly he said the interior was smaller than his 2.5"? I think as far as too restrictive remember I'm running them behind no cats, LT Headers and a 417 cu.in. motor. I'm sure the GMMG is not too restrictive for a 346..
Ed
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Old Oct 3, 2009 | 09:50 AM
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Originally Posted by BRD-PREY
I'm sure the GMMG is not too restrictive for a 346... Ed
I'm sure that's true. I would wager, though, that it's more restrictive than the better flowing catbacks like Hooker and Magnaflow.
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Old Oct 3, 2009 | 12:07 PM
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cannot beat the sound of the GMMG though
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Old Oct 3, 2009 | 04:33 PM
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Thats what eric was saying is his 2.5 powersticks would sound even deeper than my GMMG but without the restriction. Yea, Pat G said the hooker and MAgnaflow were better flowing than the GMMG. I think the 2.5 Powersticks 2 or them sound flow as well as the magnaflow or hooker.
Ed
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Old Oct 3, 2009 | 04:51 PM
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I love the sound of GMMG but I've always wondered how much power you gain with it since the GMMG website says "Dyno tested. Improved horsepower".
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Old Oct 3, 2009 | 05:01 PM
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Originally Posted by BRD-PREY
Thats what eric was saying is his 2.5 powersticks would sound even deeper than my GMMG but without the restriction. Yea, Pat G said the hooker and MAgnaflow were better flowing than the GMMG. I think the 2.5 Powersticks 2 or them sound flow as well as the magnaflow or hooker.
Ed
I can carless if I am losing < 10 RWHP with my GMMG.. Here is my set up

QTP LTs + Custom Kooks 3" O/R Y + 3" x 3.5" Flowmaster Merge + 3" Powerstick Bullet Muffler + 3" DMH E-CutOut + GMMG c/b
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Old Oct 3, 2009 | 11:18 PM
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Torchd it looks like you have stock Displacement? If so I wouldn't think you are losing any horsepower.
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Old Oct 3, 2009 | 11:24 PM
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Originally Posted by BRD-PREY
Torchd it looks like you have stock Displacement? If so I wouldn't think you are losing any horsepower.
yup stock 346 here.. but I am making some decent power for CAM ONLY still on stock 241 heads and stock ls6 intake
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Old Oct 3, 2009 | 11:32 PM
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Anybody got good quality soundclips of their exhaust with the GMMG catback?

Here is my situation. I just bought a GMMG catback. I have a set of hooker longtubes sitting in the garage for my car also. I have been debating selling the longtubes because I hear from everyone that GMMG sounds good with stock manifolds/stock cats but gets too loud and raspy when you go with longtubes and offroad Y. I want to hear some different exhaust setups with LTs, GMMG and cats or bullet in the Y pipe.
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Old Oct 3, 2009 | 11:35 PM
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Here is my idle clip.. My exhaust components are in my sig

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Old Oct 3, 2009 | 11:40 PM
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Wow it has pretty much no rasp at all. Nice car btw
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