New Member, some questions....

[kevin21]

Hey all!!

Finally paid my $20 and got on here. I'm usually on pickuptruck.com, and a "visitor" over here.

I have a 2003 GMC Duramax, I mean Sierra, and have some associated toys. I posed a question over there but I'm sure it is more applicable to this board.

Does switching out the muffler for a high-flow one, keeping the stock system, reduce the egt's? Is it that much better to go to a 4" system? Doesn't seem like .5" of diameter would help that much, but a less restrictive muffler would help??


Also, a side note, Is there a member on here with a pewter 2002-ish crew cab chevy 4x4 with a 5" chrome tip and a propane kit that lives in the Houston area?? I had an encounter with this guy on FM 2920 in Spring, TX and we both had Sh!t eatin' grin about how fast our "heavy duty" truck were!!!

Oh, and, when we both took off at the light we were at, it looked like somone started a brush fire!!! A large Black Cloud looming in the intersection!!! heheheheehehe!!!


Sorry if this is too big, but here's my truck (and 4 wheeler) at the yard.


http://img.villagephotos.com/p/2003-8/320125/DCP_1595.JPG

[Idle_Chatter]

Welcome, Kevin. Some of us have opted to just replace the stock muffler and maintain the factory 3-1/2 pipes. I did that, cut out the factory "oil drum" oval muffler and spliced in a Magnaflow 4" straight-through one with 3-1/2 x 4 reducers. The stock muffler is about 75% of the restriction in the stock system and my EGTs went down about 150 degrees with the open muffler. Pics are in the "mufflerectomy" folder in my link below.

[DMAX Daddy]

Going from 3 1/2 to 4 inch is a 30% increase in area. It doesnt seem like much, but it is.

But the muffler is the big culprit.

[sdaver]

welcome

[a bear]

Can anyone recommend a good low restriction muffler with a nice deep but rather quiet sound?
Or am I asking for too much rolled up into one?

[mackin]

Wonder if it's PEANUTGRWER ???

Oh ya welcomme ...

Mac

[Idle_Chatter]

abear, I've been happy with my Magnaflow, but I have to admit to not having anything else to compare it to.

[afp]

I did the Magnaflow thing too, and also have nothing to compare it too but I do like the low mellow rumble.

Blaine

[kevin21]

Where did you guys order the Magnaflow from and how much was it? Did they offer the reducers??

Was the install difficult?

[Idle_Chatter]

Kevin, I bought mine on the internet from www.henschelandsons.com (http://www.henschelandsons.com) in Connellsville,PA. The muffler was the Magnaflow 14771 - $149.42, the adapters were 15441 - $22.33 each. I bought 4" band clamps from a local International truck parts supplier. The job wasn't so tough, I did it in my driveway without even jacking the truck. I cut the stock muffler outlet pipe as close to the muffler as possible with a chain cutter. This allowed me to get the muffler and inlet pipe out, as well as the tailpipe. I then cut off the stock inlet as close to the muffler as possible. This left "stubs" of stock pipe inside the factory hangers. A trial fit of the muffler and clamps indicated that the adapter/muffler combo was a bit too long for the gap vacated by the stock muffler, so I trimmed about 1" off the Maganflow inlet and outlet and the same off the 3-1/2" sections of the adapters. The stubs were also oval due to both of them being in bends in the factory install. I rounded them back out for a better fit to the adapters with a 3-1/2" pipe expander tool. I then clamped the adapters to the Magnaflow and fit the three pieces back up under the truck. When I got it where I wanted it - in the factory hangers and the tip of the tailpipe supported on a floor jack, I tack welded the 3-1/2" end of the adapters to the stock pipes. Then I released the band clamps, brought out the three pieces, full welded the adapters to the pipes and put everything back. Whole job took about 4 hours.