Another Magnaflow Cat-back Installation!

[Rick]

I just installed my new Magnaflow cat-back dual exhaust system. I bought it about 10 days ago from www.premiertruckaccessories.com. I shopped around and found the best price there. $458.95 plus shipping. (You have to add the item to your cart to see the lower price!)

The install was a breeze! It only took about an hour and a half. I did have to go to Sears to buy an offset 15mm box end wrench to get the nuts off the cat connection. It was the only way I could find to access the nuts holding on the system... This is the type of wrench you need...



After taking off the two nuts that hold the pipe on... The hardest part was getting the mounting points out of the rubber keepers. You'll definitely work up a sweat doing this! It helps to use a small screwdriver to help pry it off... Then rock it back and forth and pull like hell! They are greased so after you get it started it's just a matter of working it back and forth to get the mount out.

After removing the mounts and taking off the nuts... You need to cut the exhaust pipe in order to be able to take the pipe out. (It's one unit and WAY long! I used a Sawzall with a metal blade but you could use a hacksaw.) The directions are pretty good about explaining this... And you'll see why when you take off the stock exhaust.

So now you have the stock system removed. The directions say to start at the front. I started at the rear and hung the muffler. (I really wanted to see what the tips look like!) After mounting the rear I mounted the front... Then added the connection pipe in the middle. I am very impressed with the fit of the Magnaflow system! It is a little off from the stock system as far as how the hanger line up but not by much... But the system really gives you a lot of leeway in order to move things around to make them fit. I left all the clamps loose until I had everything where I wanted it then I tightened them down. The rear tips are perfectly even and very shiny! And man do they look nice! Yeah... The hardcore wheelers are going to say they stick out too far... But I'm mainly a street driver with occasional offroad useage. If it bothers me... I'll make them removable!

Now... Starting it up was music to my ears! It sounded EXACTLY like my wifes BMW 325Xi! There is absolutely no droning while driving down the road.. Just a slight, sweet sounding rumble when you punch it off the line. The tips look SWEET on the back of the truck! I'll post pictures soon!

The only issue was the syrofoam beads that clung to the inside of the muffler and pipes. (Part of the packing broke loose and got inside. Static cling kept them in there.) After running it for a few miles I pulled over and the stink was incredible. The exhaust was smoking with the burned styrofoam. There wasn't a whole lot so I'm not too worried about it. Tomorrow I'll be putting 250 - 300 miles on it... That will definitely blow the system out! The instructions are clear in telling you that you need to make sure you adjust the pipes so that they are more than 1/2 an inch away from the body. The only place that was close was the primary muffler up front... And Hummer has a heat shield to protect the sheet metal so everything should be okay.

I'll post again tomorrow after a long road trip to fill everyone in on the performance, sound and general comments.

[ChevyHighPerformance]

"After taking off the two nuts that hold the pipe on... The hardest part was getting the mounting points out of the rubber keepers."

Push rubber back, lube post and rubber face, use channel locks from metal tip to back of rubber and squeeze, they'll come right off.

"After removing the mounts and taking off the nuts... You need to cut the exhaust pipe in order to be able to take the pipe out. (It's one unit and WAY long! I used a Sawzall with a metal blade but you could use a hacksaw.) The directions are pretty good about explaining this... And you'll see why when you take off the stock exhaust."

Jack up (not off) the rear passinger frame to lift the body (don't need to lift the rear wheel off the ground). You want to gain clearance between the rear axle and the frame. This will give you enough clearance to take the stock exhaust off in one piece from the back over the rear axle. This lets you reinstall the stock system easily incase you don't like the new exhaust.

[Idaho-Hummer]

so is there any gain to, mpg power/throttle responds, to the new exhaust so far?

[Rick]

CHP... Good points... Both of them! I thought about jacking it up. I ended up cutting it in a place that would be easy to reconnect, either by welding or by using a sleeve and clamps.

Idaho... I love it so far. I did a 300 mile trip today. I decided to take it a little easier than I usually do. Normally I'm plowing down the highway at 80 - 85 MPH. As a result I've been getting about 16.8 MPG. Today I decided to take it a little slower. Most was between 75 - 80 MPH with a few parts doing 70MPH. I filled up at the end of the day and was shocked to see 18.6 MPG!!! I'm sure a lot of it had to do with the slower speed and not "hot-dogging" the Hummer. (Not that you really can.) The "Butt Dyno" says I picked up about 10 - 15 HP minimum from the Volant CAI and dual exhaust. It is a lot peppier and has (seemingly) a lot more torque. Which is what they advertise. The throttle response is a little better but still has that slight lull before it picks up.

I reported no "droning" at speed. Well... That's not entirely true. If you are plugging along at speed on a flat surface... You really can't tell too much difference. If you are headed up hill or hit the throttle to pass or to speed up... You have a little droning. It's not offensive... But it's there. It's more of a hum than anything else. I used to ride in a Corvette that had an exhaust that would give you a headache if you drove/rode it longer than 45 minutes. The Mangnaflow is NOTHING like that.

All in all... It kinda sounds like my wifes BMW 325Xi. (Minus 1 cyclinder. heh heh) It's not quite a ricer sound but not even close to a V8. I could go for a deeper burble to the exhaust.

If you are unsure... See if you can ride with someone that has one. I'd offer to post sound clips but I don't think it would capture the essence of what this really does.

I'll keep it. I'll cap off the ends of the stock system so no critters can get in it and throw it under the deck for now... Just in case.

Rick,

Magnaflow sounds like a great deal at $458, a lot cheaper than most of these systems.

I'm running the Corsa dual outlet exhaust system with stock air cleaner. Similiar observations with the Corsa also. On the outside kind of a nice inline BMW 6 banger sound. Inside quiet at cruise on flat ground, more sound when accelerating and a bit of droning under load climbing long hills. I only feel some power increase when accelerating hard in the 4-6K rev range.

Looking forward to seeing your pics later.

S.

2006 H3
2004 986 S

[menuserve.com]

i'm curious how much the magaflow exhaust weighs compared to the stock?

[StarsnBars]

I installed my Magnaflow system myself and didnt really notice a weight diff. Muffler was about the same size as stock. same for tubes.

SnB - Magnaflow looks great on your H3. Give us some feedback when you get a few miles in.

S.

[StarsnBars]

Ive had it on for about 4 months now. The tone deepened just alittle and its holding up well. Couldnt be happier.. bUtT,, Im noticing quite alot of black carbon inside the tailpipes. Kinda seems more than normal. I dont put many miles a day on it. I guess I need to get it out and open it up more. Not sure if the muffler has changed the back pressure that much to cause more carbon buildup or possibly the motor needs serviced. I never really noticed the build-up on the stock system , but the tailpipe angled down on it. Anyone else seeing alot of carbon buildup ?? Maybe its that damm corn gas Im burning