I installed my Magnaflow Cat Back Exhaust (Twin Tips) this weekend on my 2007 H3.

Here's some pics below... I unbolted the stock exhaust from the front flange, worked my way back popping off the rubber damper/hangers one at a time and pulled the entire one piece system out the rear. Getting over the axle is a little tricky... You MUST lift the right frame in front of the rear wheel to get clearance. Be careful pulling it out. There is a brakeline going across the top of the axle and if you're careless you could damage the brakeline. I twisted the retaining band forward so the brakeline was flush with the axle as best I could.

It was pretty straight forward. The flange bolts are 15mm. you need a deep well socket to install the factory nuts on the Magnaflow pipe. They have longer studs than the factory studs.

The exhaust is nice and mellow, not as loud as I thought it might be. I've only done some tooling around town, haven't got it on the freeway yet so I can't tell you how quiet or loud it is at interstate speeds but I think it will be fine.

Here's a few pics.

 

Thats good stuff Hummer Driver. Nice job with the install and the pictures too! UPS says my intakes arives tommorow and my Magnaflow on wednesday, wooooo hoooo!

 

Looks good..How's it sound? ...Did you have any trouble with the hangers?

 

Dennis, it's actually quieter than I expected. It's a straight through exhaust system and I was worried it would rumble too much. It really doesn't, my wife said it didn't sound that different to her. I tooled around town a bit today, had my window down part of the time and I could tell a much deeper, mellower sound. Just right in my book. You do hear it when accelerating but once you're cruising it's pretty quiet.

Removing and installing the rubber hangers were the expected challenge. I dabbed some grease on the posts and rubber hangers and used a screwdriver to pry the hanger off the post while tugging on it with my other hand.

I did it by myself and it only took a couple of hours to remove and install.. It isn't easy getting the stock pipe out in one piece but like hotrodtom said, just jack it up on the frame in front of the rear tire and you'll have room to get it out between the axle and frame. If I had an extra set of hands I'm sure it would have been a little easier getting the stock exhaust out.

Thanks Obie1, you're gonna like yours too, really nice looking unit for the price. The tips are really nice with the etched logo on the top of the tips. Nice touch indeed. They say to run it of a few days and check the flange and pipe clamps. So far mine is working fine, not rattles or anything like that. It's surprising how rigid the exhaust is considering it only has two bolts at the front flange and just four rubber hangers to hold 7 feet of mufflers and exhaust pipes tucked up under the Hummer.

 

I used the screwdriver and grease bit too...What a pain...
I had the same effort to get my stock system out, I wrapped a towel around my axle so as to not screw up the brake lines....I had a set of feet and toes to help me too..LOL


Anyways, Like I said..Nice job..

I noticed in the forsale section this person selling his...seems like a good price..

https://www.hummerforums.com/m_52799..._/tm.htm#52799

 

Hmm that's weird they accepted my offer of 400 shipped... lol....

 

I got the Gibson Back Cat for $383 shipped. I plan on doing it myself. I will post pics once done. I hope it will be here Friday.

 

So is there no welding required?

 

2luke2,

No welding required on the Magnaflow, can't speak for the Gibson but I doubt it would require any welding.

My Magnaflow came in three large pieces. The front piece bolted with two bolts to the front flange. The Magnaflow has male/female tubing with two clamps to hold it together. Gotta torque'em up to about 65ft. lbs.

 

Sweet thanks that's the only reason I was even asking a shop to look at it... they are going to make me a custom pipe to knock out the 2nd cat.