JOB3

What kind of horsepower gains cann you get with the GMMG exhaust? Does anyone know? I have read all the threads on the GMMG however, no one gives this info?

PWRTRIP

I would assume its like all the others, bout 10hp..I would like to see a dyno chart comparing all of the major cat-backs along with simply a cut-out ..that would be interesting.people usually get cat-backs mainly for look/sound ..
good luck! <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

BrettD

JOB3,
I see you're right down the road from me. Wanna sell that dual/dual?

Kevin

iTrader: (1)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 2001BlackHawk:
<strong> I had SLP dual-dual and put on GMMG and had a noticeable LOSS. Was pretty disappointed. Im keeping them because of the sound though, its top notch. Good luck... </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thats odd, on the dyno the GMMG made 4 more rwhp than the dual dual.

JOB3

BrettD It might B about a month before i put on a new exhaust, however I would Prob. sell it without the tips. Keep in touch

2000LS1Z28

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 2001BlackHawk:
<strong> I had SLP dual-dual and put on GMMG and had a noticeable LOSS. Was pretty disappointed. Im keeping them because of the sound though, its top notch. Good luck... </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Did you do a dyno before and after to verify this? If not, that statement doesn't have any validity. I'm not saying you didn't lose any power but you can't just go by how the car "feels" SOTP-wise. My completely bone stock car didn't feel any faster after I added a lid & GMMG cat-back but I picked up a good amount of power on the dyno over stock. See my point? <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Mike

2000LS1Z28

And just to add to that last reply:

My 2002 Z28 with 1,263 miles dynoed @ 298rwhp & 320rwtq BONE STOCK. I re-dynoed it with 2,057 miles after the addition of a Direct-Flo lid and GMMG exhaust @ 323rwhp & 342rwtq. That is roughly a 25rwhp & 22rwtq gain from both a lid & cat-back. Its pretty apparent that each modification(including the GMMG) gave my car a good solid gain. I realize it is not an individual dyno(but close enough to show that the GMMG flows fine).

BTW, both dyno's were done at Speed Inc and all #'s are SAE corrected.

Mike

JOB3

Well i have some good info, so far but i would really like to get some more input. 700.00$ is alot just tryin' 2 get the most for the money. <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />

Buckwheat

iTrader: (13)

$700 is alot to shell out for a mediocre power increase. Have you considered the Hooker catback? $250+shipping on a group purchase through Tybyrne right now. I think the Hooker is on the same page as the GMMG as far as decibles goes and may make a few more ponies as well. The Hooker is also set apart from the rest with the black muffler that I think really sets off a set of chrome/polished tips. As mentioned on another current thread, I have seen no Hooker owners post regrets.

ArcticFormula

I think in terms of power increase, save your money, my thoughts are people buy these for the sound. At least I did. I got my 2002 Formula in August of 2001 and the only thing I have had done to date is a GMMG and BMR subframes. I only have 2500 miles on the car, and when I take to Speed Inc. this spring I am going to have them dyno it and then throw on a Stealth airbox and dyno it again. I didn't notice much of seat of the pants increase with the GMMG, but it is quiet at idle and cruise and loud enough at wide open throttle to have my *** pulled over by a bored cop, and I have stock manifolds and cats. I think it is the best of both worlds, and was worth the money.
Regards,

2001BlackHawk

I had SLP dual-dual and put on GMMG and had a noticeable LOSS. Was pretty disappointed. Im keeping them because of the sound though, its top notch. Good luck...

JOB3

Really !!!!! I also have the Dual/Dual I dont want to lose power but do want a better sound and Performance

JOB3

I have not thought about the Hooker system, Let me look into that one. I am not really into sound over performance, however I would like something with a louder better sound then the SLP Dual/Dual on my car now. I guess about all the different exhaust systems out there will give 10-15 horse so maybe I will have to pick the best sounding one to me. <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />

Classic

iTrader: (3)

JOB3 - now you're talking. Most setups will give you about the same performance so pick the sound you like the best. The GMMG is loud, second probably only to the Loudmouth in that respect, however the GMMG has a nice sound and doesn't drone on the highway to bad unless you have gears or are cruising at 90mph. You just have to decide what you are looking for the most: power (most are similar), weight, sound etc.

I will say if you go with GMMG you won't regret it, of course I bought mine for less than 600 in a GP.

Just my .02

2001BlackHawk

[/qb][/QUOTE]Did you do a dyno before and after to verify this? If not, that statement doesn't have any validity. I'm not saying you didn't lose any power but you can't just go by how the car "feels" SOTP-wise. My completely bone stock car didn't feel any faster after I added a lid & GMMG cat-back but I picked up a good amount of power on the dyno over stock. See my point? <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Mike [/QB][/QUOTE]

I understand your point completely, and I have NOT dynoed both exhaust systems therefore i cannot prove anything, however i do believe that the GMMG could make better hp, (4hp as stated by Kevin) however this is peak power at top RPM. Where i notice a loss is mid-range where you usually drive. I believe you can feel hp gain or loss if it is of substantial amount. The GMMG may peak higer but i dont believe it makes more power (area under the curve). I like the exhaust just not sure if it has as much all around hp as the SLP.

2002 CE Conv. M6

IM staying with the SLP duel / duel exhaust...I think it sounds great with headers... This is my second Trans am with this set up ... Let me make a point here for everyone , dont buy anything unless you can see it and hear it...Do it once...

JOB3

2002 CE Conv. so u like the dual/dual, then maybe i should go with headers insted of a new exhaust? does that help with sound? <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" />

ratio411

Mild to moderately modded LS1s get the same gains from most cat-backs or even just muffler changes. The .25" larger pipe is not what gives a performance boost, it is a free flowing muffler that is needed.
Get any cat-back or muffler that fits your likes as far as sound goes. Anything else is big bux for fancy tips.
Good luck
Dave