Mkos1980

iTrader: (8)

Since GMMG is out of business, the maker who made the GMMG catbacks for them still is in business and gets a big thumbs up from me. I ordered their chambered exhaust from them on thursday and it was here this morning. Each one is made to order now so it took him a few days to get everything. A+

cookie21

iTrader: (2)

glad to hear this ive been in love with those chambered catbacks since i seen the videos of the 4th gens with them on GMMG's site.

coryprine

iTrader: (4)

I have been dying to hear a good sound clip of a third gen with the gmmg....

Mkos1980

iTrader: (8)

Youtube GMMG Formula and you will see my buddys 89 Formula with a Gen I 355 and the GMMG. My car is LSX so it will sound differant.

Justin89Formy

iTrader: (26)

Mr Car oldest to newest:


http://www.youtube.com/watch?v=h0FM5eVASdM

http://www.youtube.com/watch?v=uiIsvubpzl8

http://www.youtube.com/watch?v=hd3EbmJPhsI

http://www.youtube.com/watch?v=0QwasPy-h_I

This is my latest motor. The GMMG proved to be TOO LOUD and cackly so I went with a Magnaflow

http://www.youtube.com/watch?v=5cE1gOF7iLo

3.1EyeCandy

iTrader: (3)

Got any soundclips of yours Mkos? Also - did you call or place your order through the website?

Mkos1980

iTrader: (8)

The website seems real shady so I called and spoke to Gary first. They are build to order now. He then made me go online and buy it through there. I called him on a Thursday and he mentioned he would start building it Saturday and would be able to ship on Monday. Tuesday morning it was at my door! Bummer I had to pay sales tax as their company is in Xenia Ohio. No sound clips yet. Just pics.

Thirdgen89GTA

iTrader: (5)

I gave my friend a ring about this thread. His uncle has been looking hardcore for a GMMG exhaust for his 89 GTA convertible.

diablizzard

iTrader: (8)

those clips sound nice, just probably a little too loud for a dd

Mkos1980

iTrader: (8)

Finally got to take it on the road. Yes its loud lol. But I was VERY amazed on the highway manors. 55-75 ZERO drone or interior noise. You could barely hear it. I guess the stainless works did a good job on my Y pipe to not have any drone. WOT sounds absolutely breath taking lol. Nothing like an LS motor spinning to almost 7K on the on ramp! First stop I had today was the post office and I had 2 compliments already lol. In love!!

Mkos1980

iTrader: (8)

If anybody needs detailed pics on the hangers I fabbed up for the thirdgen let me know, as the 4thgen hangers have been discontinued by GM, SLP and every other company who used to supply them with a 4thgen exhaust sold to the 3rdgen customer. Accually fabbed them up in under 10 minutes.

Carlos773

iTrader: (3)

Anyone got any detailed pictures of where the stock straight intermediate pipe ends? Want to see what bends I need to merge it to my Y pipe.

KMK454

I tried contacting Madhammer and never got any responses...

Any idea on how loud GMMG will be with factory manifolds and cats? I put a Magnaflow muffler only and it was as quiet as stock, so I switched to a Flowmaster 80 series and it's a nice volume, but its tone and character aren't what I'm looking for.

Reid Fleming

iTrader: (2)

Stock manifolds and Y-pipe, no cat, Flowmaster American Thunder (80 series).
Idle 72 dB
70 mph 80 dB
WOT 88 dB

Idle is a cold start inside the garage. 70 mph is in O/D. WOT is measured at 5000 RPM under load. "A" weighted dB scale used. All are done inside the car with the windows closed, radio off, A/C set to OFF.

Stock manifolds and Y-pipe, Catco cat, GMMG with oval tips.
Idle 73 dB
70 mph 78-80 dB
WOT 90 dB

A bit louder at idle. Hard to get a good reading on the highway as the second you lift your foot off the gas it's ultra quiet. The Flowmaster was loud all the time on the highway. The WOT figure is misleading. Although 2 dB doesn't sound like much, consider that with the GMMG I'm getting 88 dB at 4000 RPM (the same as the Flowmaster at 5000 RPM)

So basically it's going to be louder than the Flowmaster even with a cat. What the dB numbers don't tell you is how deep the system sounds. It's much deeper than the Flowmaster was.

That's a darn shame. The old SLP hangers fit like a glove. Lined up with the same bolt holes as stock. Passenger side, just reused the stock rubber block. No change needed. I'm assuming the passenger side still fits the same?

(I should mention that A weighted dB scale is more midrange and upper frequencies. I find C weighting to be more realistic, as it takes into effect low/middle/high frequencies. However Car & Driver uses A weight figures at idle/70 mph/WOT, so I wanted something to compare it too)

TransAM Joe

iTrader: (6)

SLP Hanger kit was no more than them putting GM parts together

Here are the GM Part #'s that work with all LS1 catbacks including GMMG/Madhammer to our cars: All parts are still showing current inventory

Hanger Drivers Side 10407350
Bracket Pass. Side 10272958
Washer Pass. Side 11500323
Nut Pass. Side 11516071

Rubber insulators for both sides are readily available at any auto parts store.

Drives Side is specific to 98-02 LS1
Pass. side is same from 82-02

NCGuy68

Know what you mean. I love the sound of the system on my 01 Earnhardt Intimidator SS.

hawksthirdgen

Hi,
JUst a heads up any of you guys need a exhaust kit of the GMMG chambered we have them in stock and ready to ship!.
Thanks,Bruce
www.hawksthirdgenparts.com

formula forever

I love mine. get alittle on the loud side after 70 MPH but love how deep it is.

mickeypatches

are the tips listed on madhammer's website the same as the ones on gmmg?

The Project

iTrader: (6)

Sinister put the GMMG/Madhattter on his Yellow IROC.

Sound clips of his ride are near the bottom of this thread.

http://ccfbg.com/forum/viewtopic.php?f=1&t=13502