bob320fa

So, after much dabate and saving I sunk the $850 into my new GMMG. After three weeks it arrived last night. I was so thrilled! I ran out as soon as i could today to get it put on. The downside is that after the install I wasn't quite as thrilled.
I watched the installers put it on and I will say that there was nothing they did wrong. My gripe is that for $850 plus $100 I got a cockeyed exhaust. The left side looks like it is the right height and I am generally happy with it although the exhaust pipe angles more to the right and is not centered on the facia opening. The right side is tucked as close as it can get to the gas tank without touching and it's exhaust is angled downward. On the plus side it is centered in the opening. They tried fudging with the hangers and BFMing the gas tank shield but in the end there wasn't anything to be done with the right side and the only fix was to lower the left which then would point it towards the ground. I didn't do it because I wanted to see if anyone here had any fixes and I also wanted to contact GMMG. In the end there is a 1/2" difference in height and angle. Looking at it it's VERY noticeable.
On top of it being cockeyed and pipes angling differently I paid $150 for the oval tips and got them with rust inside. Now, tips rust, I got it., but for $150 I don't think unrusted tips are too much to ask for. On the bright side they fill the openings pretty well. If they could be lined up and raised more it would be even better.
As far as sound goes I was surprised in many ways. I did know that it would be quieter on stock manifolds. It's REALLY quiet compared to my old flowmaster. It does have a nice rumble to it that I think would turn awesome with headers. It also does not have a drone on the freeway like the flowmaster which is REALLY nice.
My final review is: install - easy,
fit & finish - so/so, cockeyed
sound - good, definitely needs headers
sound level - tame
value - not worth $850 again for me. Possibly if I added the headers and a y. I just don't have the cash yet since the catback was so expensive.

8a8mfh

iTrader: (3)

A good installer could have fixed it all. Who installed it? or more specific what type of work do they usually do?
If an exhaust shop can make a whole system from scratch they can surely tweak a kit.

cookba

iTrader: (10)

i had no problems with my GMMG. and i even did it myself. the installers must have half assed it. GMMG is top notch. i like the sound of it with stock manifolds, but your right it wouldnt hurt having LT's and a catted Y to help

melchoir

iTrader: (4)

Those tips look like total ***. I wouldn't have paid an extra $150 for those, and with the rusting I can see why you would be disappointed.

GR33N GoblinM6

iTrader: (14)

umm dood what rust are you talking about?? inside the tips? thats doesnt look like rust.. looks like its discoloration from the welding of stainless..

but then again im not there in person to see it...

SIK02SS

iTrader: (11)

unless you take some time and wire brush, thas why stainless looks like after welding....b/c its going to turn black inside the tip or anything anyways


that is kind of dissapointing, hopefully you can get it figured out. and GMMG+LTs+catted y sounds great!

bob320fa

I hate to say I'm disappointed but, right now I am. As I said, i know tips rust but, would you want to pay for rusty tips? Look inside the right tip on the right side. Hard to see but, it's not discoloration. It's bright rusty....well...rust.
As far as how it sits, I didn't want the shop to do anything crazy before I contacted GMMG or, knowledgable people on this site. I watched the install, (not that I'm any kind of expert) and I couldn't see them do anything wrong. It looked pretty straight forward. The only thing I could see to do was bend the exhaust but, how hard is it to do with it on? How would you do it? We're talking significant bends. up to 1/2" or so. Soundwise it's much quieter than I hoped without spending another grand on headers/y but, I do like the tone. Much smoother. I REALLY want to be totally happy. I just need to figure out how to get there.

HAMRHEAD

iTrader: (8)

Sorry to hear about your issue. The worst part is it being cockeyed. I had a GMMG and it seemed it was a little off but never got it installed and then sold it so I couldn't be for sure. It is a quality exhaust but will sound better with LT's. With LT's you should save the money and go with a loudmouth! Hope things start going better for ya.

wannafbody

iTrader: (2)

for that price those tips should be stainless. My $25 autozone tips look just as nice.

8a8mfh

iTrader: (3)

Stainless steel rusts, ask anyone with a loudmouth. (well it stains like rust but won't pit)
I've worked with stainless quite a bit. DO NOT touch it with anything other than stainless! thats in wire brushes, steel wool, etc. You wire brush it with a steel brush and it'll never be the same.

And how do they bend the exhaust with it on the car? They don't, they take it back off.
When I was 16 I watched a guy put true duals on my friends 351W powered pinto. The pipes go on, come off get bent, go on, come off get bent, etc, etc, etc, until it's done and fits perfect.

01pewterbird

That's hanging pretty low, I thought my borla was bad. I don't see the rust though, just discolored stainless from welding, besides that will all be black in there soon enough. Have somebody adjust those pipes(or do it yourself), if it doesn't work send the pics to GMMG and see what they have to say.

JL8Jeff

iTrader: (14)

The tips are clamp on and you should be able to adjust them yourself. Unless the shop welded them crooked. If they did, I would make the shop straighten them out. You can also adjust the hanger on the passenger side by simply loosening the nut, adjust and then re-tighten. People really need to do more hands on with their cars so they know what's involved. I can't imagine paying a shop to install a cat-back. Try adjusting it yourself if they didn't weld the tips on.

SweeTbone

iTrader: (8)

Mine took a little adjustment, no more than 5 minutes and every was centered and level. Did you go to Midas or something? As for the tips, the inside will turn black real quick, so I wouldn't worry about it. I know you say it's rust, but I'm with the fellas on the welding part. Does it feel rough and crusty like rust? Hopefully you'll get squared away. Good luck.

TheSecretFormula

iTrader: (2)

That is not rust in the tips. As the other guys said when you weld stainless it discolors. It will be black in a few days. Also you should easily be able to adjust it. Any muffler shop should be able to hang a catback straight. It's pretty darn easy. Especially a top notch system like GMMG. I'll trade you my brand new SLP Loudmouth 2 if you dont like it. It's still in the box

2_wacko

iTrader: (2)

I installed my gmmg and had one problem. One side hanging lower but fixed it with a new rubber deal that go's on the hanger. I could not be happier with mine.

wild thing

iTrader: (2)

Yeah, that is not right at all. The tips are adjustable and you should be able to crawl under there and adjust them your self. They are hanging down way too low and I hate to say it but any "good" exhaust shop should have been to tackle that easily. I installed mine without a glitch. Good luck with getting everything settled out though!

STRETCH'S T/A

iTrader: (13)

I had the same issue with my left side pipe, when I installed it, it was crooked as well, I tried adjusting it on the car but it didn't help. I ended up going to a reputable exhaust shop and they took it off and heated up the left tailpipe and bent it some more. It took a couple tries, cause they went to far bending it, but they finally got it. I would contact GMMG about those tips, I know welding stainless can leave some discoloration, but I would call, or email them these pics.

ProjectCamaro

iTrader: (26)

I'm the one that bought his GMMG. Yes it was crooked, I had to do some customizing to make it straight. It's still not perfect but I haven't welded it up as it's not completely installed right now.

The only part I was dissapointed in was the welds. I don't know if it was just me but they seemed messy. I'm not a pro by any means but my welds are much cleaner than that.

02silvaZ

iTrader: (12)

someone else here posted a pic after gmmg install and it also was crooked, from what i have seen on this sight, i am not impressed for $850, gmmg can keep it

RevGTO

iTrader: (12)

Same here - my left side was crooked and had to be heated up and bent. I think the oval tips are a rip for the price - I skipped those. And the OP is right; it's a lot quieter than a Flowmaster 80 even though a lot of guys think otherwise.