How bad is the noise level inside the car with a GMMG catback??

I have been looking for a system for the Z, and GMMG seems like the most favored option.
I do a lot of highway driving, so this is a valid concern.

So what do you who actually own a GMMG think? How much louder is it inside the car than the stock exhaust?

Also,
Are there any other exhausts that aren't too loud, but have a great low rumble at idle, and an awesome roar at WOT??

 

I can't tell you much about the GMMG, except what you already know...most people seem to really like it.

I'm not going to tell you to get Corsa but I think you should consider it. I'm very happy with mine; I like the tone, the tips look great, it's very quiet when I'm just cruising on the hwy. and it screams at WOT...but I do have LTs and an ORY so that kinda changes things. I installed the Corsa just after I did the LTs & Y. The only other folks that I know (local to me) that have a Corsa catback also have full exhaust with no cats so I honestly have no idea what it sounds like with the stock manifolds and Y.

Good luck with your choice. I really don't think you could wrong with either but if there's any chance that you can hear (whatever) exhaust in-person, do it. If you're leaning towards one the higher priced systems, it'd suck to spend 600-800 bucks and end up being disappointed.

 

I heard a '99 Trans Am with the GMMG, LT's and a ORY it was insanely loud. Sounded Great though I have been told that the system w/ stock manifolds causes a drone around 2k but this is just what I have heard.

 

The GMMG sounds nice at idel and WOT, but does drone alot at cruise.
I had the GMMG now have a dynomouth. There is less drone and resonance from it. It still has the nice rumble at idle (not the same tone though)and screams at WOT.
Also considerable cheaper. The GMMG intimedator tips are awesome though.

 

The GMMG sounds absolutely awesome at cruise, highway and WOT!! Heading out to my car every morning to start it is very exciting Best sounding catback you can buy for the LS1. You can get it for $650 shipped through group purchase at http://www.f-bodyhideout.com Contact SleeperZ96BT for details.

GMMG

 

You should consider milder catbacks if highway drone is a concern. Corsa or Hooker would probably be better choices for someone who spends a lot of time at 2k rpms and is bothered by drone.

Good Luck

 

One question....

Would dynamatting everything behind the rear seats solve the problem of the "drone"???

 

There is no drone. It depends on how you drive it. Driving it normally has no drone. Trust me, you'll love the GMMG. Not obnoxious like the loudmouth

 

All loud exhausts including GMMG have some degrees of drone. Some are worse then others but you will notice it on any of the louder setups especially if you have LT's and are catless.

The real question is can you live with a little drone. Most people drown it out by cranking thier sterio but if you spend a lot of time on a cell phone that would cause some issues I suppose.

I'm not sure how much dynamatting would help or not. Believe me when I say drone gets annoying real fast when you are cruising on a highway at 2000-2500 rpm's with the windows up and radio off. It's tolerable but after 30 minutes you'll find yourself wishing you had ear plugs. Anyone with an A4 car and loud exhaust knows all too well what drone is all about. M6 guys get away with it easier because 6th gear is a blessing on the highway to keep them out of drone rpm's.

I really think you'd be happier with Corsa or Hooker if drone bothers you a lot. You could always add an electric cutout so you can be loud when you want and peaceful quiet when you don't.

Good Luck

 

Its not a bothersome drone that will hurt your ears. It sounds awesome. Corsa = too quiet :blah:
Loudmouth = too loud/raspy
GMMG = just right

 

I would expect that from an M6 guy. No offense to the GMMG. I agree it's an awesome sound and probably the best catback for a LS1. But drone from the perspective of a M6 car with a 6th gear that allows you to cruise well under 2k rpm's is way different from the drone an A4 hears when his rpm's are up in the 2200-2500 range. It's not bad with the windows down and or tops off. But when you got the windows up and the radio down a 75-85 mph cruising speed can be annoying in the A4 if you have a long trip ahead of you.

I love my dynomouth setup very much but I have to admit the highway drone can be a bit annoying. Just like the GMMG it's no where near as bad as the loudmouth but it still exists and is far more annoying in automatics then manuals.

If at all possible I would go to the local track (if you live in an area where one is still open) and talk to all the ls1 guys there. Find one with an A4 and GMMG and ask to go for a ride where he puts up the windows and cruises at 70ish mph. That's probably the only way to know before you buy it if you would mind it or not. Like omega said it's no where near as loud of drone as the slp loudmouth but it does have some as do all louder exhaust setups.

The drone won't be too bad but at 2500-3000 rpm's it kind of makes your ears feel like they do when you go swimming and get water in them. It's like a preasue that's hard to describe. It's not loud where you can't have a conversation but it's annoying because it feels wierd.

But hey, you can always try the GMMG and if you find it's drone too much for you then pull it off asap and sell it. You'll either love it and keep or or you'll get most of your money back and can get a hooker catback or something.

Good Luck with your car

 

out of the catbacks i have heard the gmmg has little interior noise even with headers and cats it isn't much with off road pipes though holy **** that thing is loud everywhere.

 

Maybe with the stock manifolds and Y it is but with LTs and an ORY...quiet is the last thing Corsa is. It can be quiet when I want it to be (that's what I like about it) but at WOT, this car is every bit as loud as my '96 with LTs, ORY and Borla (w/ no plate) was.

 

Here are some sound clips while driving inside the car.

Mods were longtubes, cats, and GMMG.

I don't think it drones.

There's another one after the cam and stuff. It got a lot louder.

 

I don't care for my SLP cat back