slvrbird2000

IMHO there is no substitute for the real GMMG. It has been "duplicated" before with poor results. I would buy the system, $650 on the GP is the normal amount of other high quality catbacks out there like Corsa, Borla, Triflow...

Scott

ratio411

A couple guys over at LS1.com have done this... The labor was a little over $200. I don't see how it could be duplicated on one hand, but be called "poor result" on the other. Sounds perfectly reasonable if that is what you want.

FAST LS1

iTrader: (2)

I've almost decided on making my own after seeing how much the GMMG exhaust retails for, even in GP's <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />

I really looked into making a comparable exhaust and here's what I came up with.

Over the Axle Pipe = $49.99
Flowmaster Y-Collector = $37.99
2, 18in Chambered Pipes = $94.50
2 Stainless Mandrel J Bends = $51.98
Add about $20-30 for shipping and Handling
Good exhaust shop should be able to fab it all up from GMMG's pic for about $50-100.

Total = $305-365
I'm taking into account the use of the mandrel 90 degree bends on the stock exhaust for the tailpipes and using the stock tips.
To do the whole thing you'd need another J bend and your choice of tips. Still much less than $700.
Here's what the GMMG looks like for Reference GMMG Exhaust

<small>[ November 08, 2002, 12:09 PM: Message edited by: FAST LS1 ]</small>

Matt Johnson

I am looking to do the same thing but will not be using y-pipe and be using a true dual config and having some high flow cats near the headers.

FAST LS1

iTrader: (2)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by slvrbird2000:
<strong>IMHO there is no substitute for the real GMMG. Scott</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The only difference in the real GMMG and the parts list I made out are the chambered mufflers. I don't know how much they vary, but technically those parts that cost $230 are the same thing as the GMMG exhaust minus welding? After really looking at the chambered mufflers they look pretty restrictive compared to Bullets.
I'll probably end up with the Dynomouth style setup with 2 bullets in the I-pipe and stock tips. The GMMG does sound good, but I just can't justify $650 when the parts alone only cost $230 retail <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" />

Ron@Vengeance

iTrader: (51)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by FAST LS1:
<strong> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by slvrbird2000:
<strong>IMHO there is no substitute for the real GMMG. Scott</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The only difference in the real GMMG and the parts list I made out are the chambered mufflers. I don't know how much they vary, but technically those parts that cost $230 are the same thing as the GMMG exhaust minus welding? After really looking at the chambered mufflers they look pretty restrictive compared to Bullets.
I'll probably end up with the Dynomouth style setup with 2 bullets in the I-pipe and stock tips. The GMMG does sound good, but I just can't justify $650 when the parts alone only cost $230 retail <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">All Ive got to say is ya get what ya pay for.

230 parts+ 200 to weld it all up(hope the guy has as nice of weld beads as the chambered systems I have seen)+ shipping(about 65 bucks) Thats 500 bucks alone with the hope it turns out as nice as a true chambered. The system only retails for 700 to your door. I wouldnt risk it in my opinion.

BTW, I regarding your thoughts on the chambers being restrictive, I saw a back to back dyno the other night with a modded LS1. Car only picked up 6rhp with a 3" cutout over the chambered system. That says it must flow quite well.

BEst of wishes on your homemade masterpiece

FAST LS1

iTrader: (2)

I guess the welds won't look as pretty, but it's still technically the same exhaust. Just like a cutout is the same thing as a Borla with the open plate. It might look better, but it's same thing. I just looked into it as an option since even $650 is too much change for me.
6rwhp seems comparable to what most cat-backs loose when capped. That's enough hp for me not to get chambered mufflers and stick with bullets.

DinoZ

iTrader: (5)

I went with the Dynomouth... parts and labor for $125!!! The quality of the work excedes any premanufactured that I have seen yet! Two guys with Borla's heard my exhaust, and the next week were taking their Borla's off, because they want a Dynomouth! I also have a freind with a LM, who is pizzed off, because he spent over 3 times as much as I did, and mine sounds way better!

Good luck to you and your home made GMMG, sometimes custom work is just as good if not better than the original design!

Blue Meanie-

The Sweet Thunder Chambered pipes are very different than the chanbered pipes on the GMMG, I actually planned on making the cheap system through them, but passed because the largest chamber is 3" and only has a 2.5" inner diameter. The inside of the mufflers are different. I will be making my side exhaust on my LT1 with Sweet thunder pipes, since it would be true duals I can go to 2.5" exhaust. The sweet thunder pipes are awesome, its just that in order to do a stainless system, you would have to buy stainless intermediate pipes and exhaust pipes. Which would negate any cost savings. And I can tell you that a mirror polished GMMG is a beautiful thing. I just did mine yesterday.

scot

I can't tell you that the GMMG is worth the price in terms of flow or even sound.I can say that vibration, drone and rasp are so much better on the GMMG than all the loud systems I've heard that it made the price worth it to me.