Does removing the muffler on a stock exhaust reduce EGT's enough to run a mild tune? Maybe 70hp or less.

I would say yes, the stock muffler is very restrictive. At one point it is reduced inside to 2 1/4".

I cut out my OEM muffler and spliced a Magnaflow 4" straight-through muffler into my OEM pipes and EGTs went down 150-200 degrees "across the board."

Can't tell you about EGT's, but after I took the stock muffler off of the truck and put on a magnaflow muffler I noticed a 1-1.5 mpg increase. The magnaflow sounds just as quiet as stock. I was going to straight pipe it, but I was worried about how loud it would be.

Tony P.

I think I will go for it then. A cat-back sounds great but a new muffler is much cheaper. I would think the difference in MPG and in lower EGT's would be great for the truck and for my wallet. Thanks for the replies.

What I have found after running a stock muffler, gutted stock muffler, straight pipe and MBRP muffler is that for the most part cruising EGT's stay the same no matter what you are running... where the straight pipe or performance muffler comes in is when you floor it and keep on it, that is when it becomes effective and EGT's don't get quite as high as a stock system...

Dan

Idle Chatter and Pesty3782,

Do you remember the model number of the Magnaflow muffler you used, or what the length of the muffler is? I noticed that they have different length diesel mufflers, and was wondering if it's better to use one length over another.

Thanks,

Joseph

Before removing the OE muffler and replacing it with a 4" straight through design, while towing my trailer up moderate grades in cool weather I would frequently see 1100 - 1200+ degrees on the pyro. Now, I’ll see that on a hot day with the AC on climbing similar grades with the Juice set at level 1.

TC

I have been thinking about this approach too, I like it! Can anyone tell me if someone makes a 5"-4" reduction collar, so you can use straps to do the install? Otherwise, I will probably take it to Mighty Muffler here in Phoenix and have them weld a performance muffler in place with the stock exhaust.

Has anybody noticed and difference in HP/torque values? I don't really care if I get significant gains, but I don't want any reductions. I thought this could be a concern since the performance mufflers are usually designed in conjunction with the pipe.

Thanks!

Out!

Idle Chatter and Pesty3782,

Do you remember the model number of the Magnaflow muffler you used, or what the length of the muffler is? I noticed that they have different length diesel mufflers, and was wondering if it's better to use one length over another.

Thanks,

Joseph

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 Magnaflow 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.

Just another thought...

If you bought a "straight pipe" kit from a vendor here, would that allow you remove the stock muffler, use the pieces from the straight pipe kit but put the muffler in place of the straight pipe? I'm thinking this would eliminate welding the pipes together at a slight angle. The draw back, could be that the straight pipe kit could be too long, and not allow enough room for the muffler.

I might be completely out to lunch here, and if so, let me know.

Thanks,
Steve

I checked with 2 local mufflers shops about getting duel straight pipes.I would settle for a muffler back duel setup but I was told I would have to remount my spair because they couldnt bend around it.Well that was a deal killer,I dont want the spair in my bed.So I ask about a single straight 3.5" pipe and was quoted $95.00.I thought that was way to much for so little work.I called around and the price is the same everywhere.
Something I've been wondering about , is there any reason I can't come off the driver side manifold and go straight back for my duels?The only thing I can think of is that it mite interfear with the turbo or something.
Any ideas?

Yeah they want a lot at shops for a 3 1/2" piece of pipe.I got mine free at a scrap yard one day when I was looking for some truck parts.

Replacing the stock muffler is good for 10-15 HP, if using a tuner.

I happen to have a new 14772 SS Magnaflow, 6" longer than the 771. I won't be using it. I will let it go for $95. Posting here on opportunity.

Beekiller@cox.net.

I cant believe some vendor hasnt jumped on this and marketed a "muffler delete" pipe. It cant be that expensive to make, seems like some budget horsepower to me.

The muffler delete pipe is $45 on e-bay. Clamps are $5 more and shipping is $15.

Went to local shop and had mufflerectomy today. They charged me $70 even and I was on my way in about 1/2 hour. Truck is still stock and don't notice any difference in power or spool up. It sounds good and can't even tell anyhting was changed from inside the cab. The only diiference I can tell from stock is now the pressure coming out the tailpipe is much lower. With the stock setup it seemed to be thrown out the back and now it is at a much slower velocity. Didn't expec that but I guess if there is less backpressure then it won't shoot out quite as hard? Ayway it seemed like a good deal seeing as how on the '05 the muffler is offset and the pipe needed two bends. That and the fact that it is now welded instead of straps I'm pretty pleased.