I got my gmmg installed this morning. On my way to speed inc I got on it a bit once it was warmed up and it seemed so sluggish compared to how it feels now. I never would have imagined the stock catback was so restrictive. Headers, CHECK!... Catback, CHECK! ORP, CHECK!... but it does sound raspy above 2500 rpm. Just gives me a reason to put the catalytic on and avoid trouble/fines.

I would recommend it to anybody who wants a new exhaust. While I was waiting for them to bring the car out there were a few people who waiting for a dyno and they thought it sounded really good too.

The only problem I have with it is that the tips arent even since its an ls1 catback. Has anybody else had problems with this? Currently the tip on the drivers side is a couple cm behind the passenger side, and is causing soot to accumulate on my rear bumper. (Im also running pretty rich)

 

Great choice man. I had the hooker cb before and when i got my gmmg installed damme what a difference. I couldn't believe how deep and mean it sounded. For about a week i wasn't getting any rasp or popping now the exhaust pops and little What makes you think your running rich? How can you tell?

 

I have a slight exhaust leak from when i installed my header gaskets, im just too damn lazy to fix it, plus i dont have a cat so i dont have to worry about clogging that. but yeah im thrilled with it so far. I just cant rev it in my driveway (i told my mom it wasnt much louder than stock) hahahaha

 

My driver's side tip sticks out a few cm more as well. I have the LT1 system so it should fit. No biggie though. I use the removable tips to fine tune the look. I slide the drivers side tip on further and the passenger tip on less.

Kyzer: I had a Hooker catback before GMMG too. And yes...what a difference.

I've had people ask me if I'm running a straight pipe. It's a little loud. I can't wait to hear it with LT's.

 

I have midlengths, I now wonder how much quieter it would be with the stock manifolds...

 

I ran the car without a muffler when I was going between the hooker and gmmg. It sounded pretty mean. I could feel the sound in my chest when I was accelerating. My exhaust now isn't nearly as loud.

At idle it's louder than stock but not as loud as the open pipes obviously. It's more of a refined sound with that good old V8 rumble.

 

Glad to hear that..I just cant justify spending that much for a catback

 

I used to say that too...

 

I hear you antz I bought my gmmg used for $500...... not bad price.

 

Hey Kyzer,

How did your sound change with the LT's? That is if they were done after the catback.

Also, did you pass the sniffer with the LT's? I know they don't have a carb number but that can be over looked...

 

Terlox I had the lt's on already when i installed the gmmg. I had a hooker cb and lt's then switched to the gmmg. I haven't had a smog yet so i'll keep you posted. Im not to worried about it theirs so many CA people with lt's and passing.