Generation III External Engine LS1 | LS6 | Bolt-Ons | Intakes | Exhaust | Ignition | Accessories
Sponsored by:
Sponsored by:

Massive GMMG drone problem

Thread Tools
 
Search this Thread
 
Old Mar 31, 2019 | 07:15 PM
  #21  
99TransAmDude's Avatar
Thread Starter
Staging Lane
 
Joined: Mar 2011
Posts: 63
Likes: 4
From: Chicago Area
Default

Originally Posted by wannafbody
Might have to do with the different cams used in 98-00 and 01 and 02.

Yeah, 2001,2002 have different manifolds, cat converters, and intake manifold. Might be something to do with any one of those. I'll see how it goes when I get the custom I-pipe and put it back on.
Reply
Old Mar 31, 2019 | 08:22 PM
  #22  
99Silver6.0's Avatar
TECH Veteran
20 Year Member
Liked
Loved
Community Favorite
iTrader: (2)
 
Joined: May 2002
Posts: 4,440
Likes: 93
From: Spring Hill, KS
Default

Originally Posted by 99TransAmDude
I'll definitely update to say how it goes. Gary is a great guy. He makes a really nice quality system. I'm still confused though why my 2001 is so different than my 2000 and 1999 with this cat-back. Oh well, we'll see how it goes.
Not sure man. Im sure the muffler I-pipe will work well for you. Post some pictures of it too! I still might try one. I love My setup I got from him. I’d have a hard time parting with it to be quite honest. Little raspy but sounds mean as hell!
Reply
Old Apr 3, 2019 | 11:02 PM
  #23  
RevGTO's Avatar
Pontiacerator
20 Year Member
Photogenic
Liked
Loved
iTrader: (12)
 
Joined: Nov 2003
Posts: 6,216
Likes: 236
From: Wichita KS / Rancho San Diego
Default

2000-2002 manifolds and converters are the same, except for the right manifold EGR provision in 2000. I can't see that, the LS6 intake, or the slightly different cam having any noticeable effect. Your symptom is very strange.

My 2000 with GMMG had zero drone at highway speeds with stock manifolds and converters. LT's and ORY was a different story
Reply
Old Apr 8, 2019 | 07:57 PM
  #24  
99TransAmDude's Avatar
Thread Starter
Staging Lane
 
Joined: Mar 2011
Posts: 63
Likes: 4
From: Chicago Area
Default

Originally Posted by RevGTO
2000-2002 manifolds and converters are the same, except for the right manifold EGR provision in 2000. I can't see that, the LS6 intake, or the slightly different cam having any noticeable effect. Your symptom is very strange.

My 2000 with GMMG had zero drone at highway speeds with stock manifolds and converters. LT's and ORY was a different story

Yeah, I had a GMMG on my 2000 Trans Am as well. I had it with stock manifolds and cats, then I swapped it out for Edelbrock shorty headers and high flow cats and had zero drone issues. My 99 is the same boat, no problems. That's why I'm so confused on this car since it's 100% stock.
Reply
Old Apr 8, 2019 | 07:58 PM
  #25  
99TransAmDude's Avatar
Thread Starter
Staging Lane
 
Joined: Mar 2011
Posts: 63
Likes: 4
From: Chicago Area
Default

Gary sent me a new I-Pipe with mini muffler built in. Looks just like the normal GMMG with the pushed in sections. It also has a small baffle inside as well. I'm going to install it tomorrow night.
Reply
Old Apr 8, 2019 | 08:52 PM
  #26  
99Silver6.0's Avatar
TECH Veteran
20 Year Member
Liked
Loved
Community Favorite
iTrader: (2)
 
Joined: May 2002
Posts: 4,440
Likes: 93
From: Spring Hill, KS
Default

Originally Posted by 99TransAmDude
Gary sent me a new I-Pipe with mini muffler built in. Looks just like the normal GMMG with the pushed in sections. It also has a small baffle inside as well. I'm going to install it tomorrow night.
Post up a few pics of that thing if you can!!
Reply
Old Apr 11, 2019 | 05:49 AM
  #27  
99TransAmDude's Avatar
Thread Starter
Staging Lane
 
Joined: Mar 2011
Posts: 63
Likes: 4
From: Chicago Area
Default

Originally Posted by 99Silver6.0
Post up a few pics of that thing if you can!!
What do people use to post pictures on forums now a days? I haven't used Photobucket in like 5 years and looks like they want you to pay now.
Reply
Old Apr 15, 2019 | 08:51 AM
  #28  
99TransAmDude's Avatar
Thread Starter
Staging Lane
 
Joined: Mar 2011
Posts: 63
Likes: 4
From: Chicago Area
Default

The new i-pipe with mini chambered gmmg muffler worked out. The car is just as loud but it got rid of the intense drone at 2200rpm. It's still slightly there but I'd say 85% gone. It's definitely liveable. It actually gave the exhaust more of a rumble too. When I accelerate really slowly (maybe 1/4 throttle) it has a super deep rumble. I really like the tone. It wasn't like that before the modified i-pipe. This weekend I'll try and make a YouTube video if the weather cooperates.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
Old Apr 15, 2019 | 09:27 AM
  #29  
Kfxguy's Avatar
TECH Veteran
5 Year Member
Liked
Loved
Community Favorite
iTrader: (1)
 
Joined: Apr 2017
Posts: 4,582
Likes: 758
From: Louisiana
Default

Originally Posted by 99TransAmDude
The new i-pipe with mini chambered gmmg muffler worked out. The car is just as loud but it got rid of the intense drone at 2200rpm. It's still slightly there but I'd say 85% gone. It's definitely liveable. It actually gave the exhaust more of a rumble too. When I accelerate really slowly (maybe 1/4 throttle) it has a super deep rumble. I really like the tone. It wasn't like that before the modified i-pipe. This weekend I'll try and make a YouTube video if the weather cooperates.

So you added a helmholtz to it?
Reply
Old Apr 15, 2019 | 10:57 PM
  #30  
wannafbody's Avatar
TECH Senior Member
20 Year Member
Community Builder
Liked
Loved
iTrader: (3)
 
Joined: Apr 2006
Posts: 5,605
Likes: 1,150
From: Pittsburgh
Default

No he had a chambered stick muffler added to the single I pipe
Reply
Old Apr 16, 2019 | 01:32 PM
  #31  
99Silver6.0's Avatar
TECH Veteran
20 Year Member
Liked
Loved
Community Favorite
iTrader: (2)
 
Joined: May 2002
Posts: 4,440
Likes: 93
From: Spring Hill, KS
Default

Originally Posted by 99TransAmDude
The new i-pipe with mini chambered gmmg muffler worked out. The car is just as loud but it got rid of the intense drone at 2200rpm. It's still slightly there but I'd say 85% gone. It's definitely liveable. It actually gave the exhaust more of a rumble too. When I accelerate really slowly (maybe 1/4 throttle) it has a super deep rumble. I really like the tone. It wasn't like that before the modified i-pipe. This weekend I'll try and make a YouTube video if the weather cooperates.
Did the ID of that pipe look decent? Didnt choke down really small did it? They way the he constructed the pipe made it sound like it would have an ID of like 2.4".

"Yes, I take a 2.375" SS louver and wrap it in SS wool, which then goes into a 3" tube. Size and crimp."

Just seemed a bit on the small side. This is a picture I found on Tech a few months ago.

Reply
Old Apr 16, 2019 | 07:20 PM
  #32  
99TransAmDude's Avatar
Thread Starter
Staging Lane
 
Joined: Mar 2011
Posts: 63
Likes: 4
From: Chicago Area
Default

Originally Posted by 99Silver6.0
Did the ID of that pipe look decent? Didnt choke down really small did it? They way the he constructed the pipe made it sound like it would have an ID of like 2.4".

"Yes, I take a 2.375" SS louver and wrap it in SS wool, which then goes into a 3" tube. Size and crimp."

Just seemed a bit on the small side. This is a picture I found on Tech a few months ago.

I do have a picture, just not sure how to add it to here since photobucket doesn't seem to be free anymore. It does choke down a bit. I'd guess maybe 2.6" ID where the baffling is. Not crazy about that part but it does sound pretty cool with it. If I lost 5-10hp, I really don't care. At least my ears wont bleed. lol. I already ordered up a medium powerstick. I might get it made into an I-pipe and try it out to see what the difference is. The only thing I don't like about the powerstick is it's not stainless and I daily drive this TA, even through the winter.
Reply
Old Apr 30, 2019 | 08:44 AM
  #33  
99TransAmDude's Avatar
Thread Starter
Staging Lane
 
Joined: Mar 2011
Posts: 63
Likes: 4
From: Chicago Area
Default Update 2

I bought a medium powerstick and had an exhaust shop build it into another I-pipe. I pulled the gmmg custom i-pipe with mini muffler and installed the powerstick one....what an amazing difference. The gmmg one still put out more of a constant tone around 2300rpm with a little drone. The powerstick mated to the gmmg catback gives a nice rumbly sound. It reminds me of an old school muscle car. Around 2300 rpm there is zero drone and it does not put out the annoying constant tone. It's a super deep rumble that I can actually feel in my seat. I absolutely love it. The setup is pretty quiet at a constant speed on the highway but if I give it just a hair more gas, you can hear it come to life. WOT is music to my ears. I'm finally done. Gmmg muffler setup and a medium powerstick...the perfect combo on a stock 2001 WS6.
Reply
Old May 3, 2019 | 05:59 PM
  #34  
Majestic9C1's Avatar
TECH Fanatic
10 Year Member
Liked
iTrader: (19)
 
Joined: Jun 2013
Posts: 1,667
Likes: 22
From: Cincinnati, OH
Default

got a part number by chance on the Powerstick?
Reply
Old Jan 28, 2021 | 08:16 AM
  #35  
PunisherSS01's Avatar
Teching In
 
Joined: May 2006
Posts: 27
Likes: 1
From: San Antonio
Default

I just put a GMMG on my '01 SS with 14k miles on it that is bone stock and the Drone is Terrible. Really wish i could see what you put on yours so I could do the same to mine. What was the part number or size to the medium power stick that you put on?
Reply




All times are GMT -5. The time now is 08:33 PM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE