Massive GMMG drone problem
Thread Starter
Staging Lane
Joined: Mar 2011
Posts: 63
Likes: 4
From: Chicago Area
Massive GMMG drone problem So I'm a little confused. I installed a GMMG catback on my bone stock 2001 trans am yesterday and the drone is terrible. My ears actually ache from just 2 days of driving just 20 miles round trip. It's not a loudness problem. It's just that pressure you feel in your ears over 1500rpm.
This isn't my first GMMG. I also have a 99 trans am with shorty headers and it sounds great on there. I just sold my 2000 Trans am that also had a GMMG catback on it. It was stock as well and had no problem. I don't understand why my 2001 is so much different. The car came with a LM1 and it was okay, just the typical 2500rpm drone everyone mentions. I converted it to a borlamouth...bad drone. Next I put a TSP catback on which was okay but too quiet. Zero drone though. Now I have the GMMG. I might be going back to the TSP and just live with the slightly too quiet exhaust. At least my ear drums won't bleed. Lol
This isn't my first GMMG. I also have a 99 trans am with shorty headers and it sounds great on there. I just sold my 2000 Trans am that also had a GMMG catback on it. It was stock as well and had no problem. I don't understand why my 2001 is so much different. The car came with a LM1 and it was okay, just the typical 2500rpm drone everyone mentions. I converted it to a borlamouth...bad drone. Next I put a TSP catback on which was okay but too quiet. Zero drone though. Now I have the GMMG. I might be going back to the TSP and just live with the slightly too quiet exhaust. At least my ear drums won't bleed. Lol
btw, if you like the way it sounds and the volume of it.....its just the drone thats messing you up, look up helmholtz resonator. i built some for my car and they got rid of 80-90% of the drone. Or you could put a turbo on it. That eliminated the drone 100% LOL
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Staging Lane
Joined: Mar 2011
Posts: 63
Likes: 4
From: Chicago Area
The bushings are all good. The trans am only has 13k miles on it. It's definitely not touching anywhere. I ran my hand along the pipe. It's really close to the heat shiled where it clears the panhard rod but definitely doesn't touch.
Thread Starter
Staging Lane
Joined: Mar 2011
Posts: 63
Likes: 4
From: Chicago Area
Never heard of that. I'll look it up. Yeah a turbo would be nice. 😃
Thats crazy, my GMMG doesnt drone at all now. It did some with stock Y and cats though! Im going to get a Magnaflow 14419 to try and tone down the rasp a bit. Gonna cut the 2.75" reducer off the end of the ORY, cut down my intermediate pipe and use the muffler to couple my exhaust to the Y and be a full 3".
Thread Starter
Staging Lane
Joined: Mar 2011
Posts: 63
Likes: 4
From: Chicago Area
Thats crazy, my GMMG doesnt drone at all now. It did some with stock Y and cats though! Im going to get a Magnaflow 14419 to try and tone down the rasp a bit. Gonna cut the 2.75" reducer off the end of the ORY, cut down my intermediate pipe and use the muffler to couple my exhaust to the Y and be a full 3".
Let us know how that works. I did email Gary about that same pipe. Only thing that I was was worried about was the ID of the pipe after it gets crimped is a tad tight.
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Thread Starter
Staging Lane
Joined: Mar 2011
Posts: 63
Likes: 4
From: Chicago Area
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.
Thread Starter
Staging Lane
Joined: Mar 2011
Posts: 63
Likes: 4
From: Chicago Area