GMMG vs. True duals

**Deaton52** · 09-17-2007, 08:40 PM

My car is bone stock right now. I really wanted to do true duals on my car. I wanted LT, no cats, h-pipe, flowmaster 1-chambers all the way out the back. However, it has been rather difficult finding an exhaust shop close to me that will do true duals. So as an alternative I was thinking of the Gmmg. Compared to the true dual system; I wanted to know how much louder would the duals actually be over the catback. I realize performance will be better with the duals but, I want to know if there is a big difference in decibal level and tone between the two.

**0rion** · 09-17-2007, 08:59 PM

There was a local cammed car running a GMMG with LT's and no cats. At WOT it made grown men wet their pants. If I ever replace my current catback with something other than duals it'll definitely be a GMMG.

**SIK02SS** · 09-18-2007, 09:31 AM

GMMG sounds awesome on stock manifolds. with LTs its a quiet rumble at idle, quiet with normal driving, and screams at WOT. TDs are loud at idle, loud at normal driving, and screams louder at WOT (think racecar loud..at least mine is)

**Blue_98_ws6** · 09-18-2007, 10:11 AM

wait i know this is pry a dumb question but whats a gmmg

**secondgearscratch** · 09-18-2007, 10:42 AM

Originally Posted by Blue_98_ws6

wait i know this is pry a dumb question but whats a gmmg

just a brand of catback exhaust. they use bullet style mufflers. great quality and sound.

**Blue_98_ws6** · 09-18-2007, 10:55 AM

never heard of them i was gonna go with flowmaster but i just found another thread about true duals thats like 5 pages long and i think im gonna do that now it definitely seems better

**jd2002ss** · 09-18-2007, 04:31 PM

My car has GMMG w/ cats, Kooks headers and Y pipe. Comp 228/230 112 cam. It dyno'd at 405hp after tuning. The sound at idle is as sweet as it gets. At mild acceleration they know your coming, at WOT they run for cover!!! Highway speeds in 6th gear is very tolarable, I'm happy with my choice.

**blue02Z** · 09-19-2007, 06:48 PM

can we get some sound clips please? i like gmmg and would like to hear it on your ride

**SSwt00SS** · 09-20-2007, 06:18 AM

Originally Posted by blue02Z

can we get some sound clips please? i like gmmg and would like to hear it on your ride

www.ls1sounds.com

**nomorefords** · 09-20-2007, 07:45 AM

i have true duals w/gmmg muffs they aren't loud at idle but give a great sound under load and at WOT they're beautiful! Mandrel bend out through the back! I love them, they're low so if you're going with suspension NO lower then a pro-kit, but well worth the time and $$$ for GMMG!!!!