Muffler Options?

uncle ned · April 28, 2015, 05:54:45 PM

At times like this being a good friend with Ken Arnold might be a good idea

uncle ned

Lostranger · April 29, 2015, 06:10:32 PM

New muffler arrived today. UPS damaged it, of course, but nothing I can't straighten:

Tomorrow I'm gonna attempt to swap it into this space:

And silly me, I finally paid enough attention to see that I had been measuring the lower end of an adapter clamp rather than the muffler inlet. In my defense, it's been dark and I was in a hurry both times I measured, but mea culpa. My new muffler has 5" inlet, and that MAY be perfect:

More tomorrow night. Wish me luck.

Jim

P.S. I hate TinyPic. All of these images were rotated 90 degrees left, and I can find no way around it.

TomC · April 30, 2015, 08:40:42 AM

That's going to be a hard switch over. Why didn't you buy an oval muffler like what you have? That long muffler is going to be a PITA to try to get in. I would return that muffler (the damage is a good excuse) and look again for a more suitable one. Good Luck, TomC

Jim Eh. · April 30, 2015, 11:38:20 AM

Where is the outlet on your original muffler?

They usually don't make catalytic mufflers in an oval format but it is possible I guess. Navistar added in a catalytic section to their in use mufflers in the beginning (early 2K) to experiment with which were 8.3" x 11" but switched to round for the actual production models.

That OEM muffler is double wrapped (outer jacket is crimped onto the edge of the body) meaning it is quieter than your chosen one both noise transmission through the muffler body itself plus higher exhaust noise level out the pipe. Some like it that way though.
This is due to the fact the original runs through a series of baffles (not a direct flow with possible one baffle like your Donaldson vertical version).

Most any 10x15 oval muffler is going to run you close to $200.00 and if it is double wrapped add some more. In the long run it may be better to spend some extra now and enjoy a quieter drive later but like I said, some like it loud(er).

Lostranger · May 07, 2015, 07:39:38 PM

Finally, 8 days after starting, I have the muffler job finished. Wasn't working on it all that time, of course, but it was certainly on my mind while I attended to other stuff that jumped in my face.

Tom and Jim, thanks for posting. I certainly appreciate your help.

I've posted the full update on my build blog: http://nomadicista.org/viewtopic.php?f=4&t=2541&p=20880#p20880

Here are the highlights. I started with this:

And ended with this:

Once again, TinyPic is rotating my photos 90 degrees left. Sorry. Nothing I can do.

I love the new muffler. Maybe a bit louder — only time I notice is when I'm driving beside a building — but it fits the space better, and the acceleration is dramatically improved. Can't wait to check MPG.

New upper mount came out well:

With the hatches closed, no one would know it isn't stock.

I saved at least 70 pounds in this swap. I spent $120 on parts/shipping, and best of all, any future muffler swap will be quick, easy and inexpensive.

Glad the old one blew. It was an excellent excuse for an upgrade.

Jim

Oonrahnjay · May 09, 2015, 08:30:31 AM

Quote from: Lostranger on May 07, 2015, 07:39:38 PM... Glad the old one blew. It was an excellent excuse for an upgrade.

Jim

Good looking work, Jim. I hope to be there in a few weeks and I'm bookmarking your photos.

Dave5Cs · May 09, 2015, 11:26:43 AM

Great job Jim looks clean, mea maxima culpa, lol

Dave5Cs

Jim Eh. · May 12, 2015, 09:25:28 AM

Nice work. If heat gets to be an issue you can install a diffuser upstream of the muffler, given sufficient straight tubing section.

Lostranger · May 12, 2015, 11:11:42 AM

Jim, where are you thinking heat might be a problem?

Jim Eh. · May 13, 2015, 04:43:31 AM

Just based on the fact the OEM was double wrapped. Not only does it reduce noise it reduces the heat of the surrounding area. If that was one of the original design criteria then some concideration may need to be given to the heat issue.

luvrbus · May 13, 2015, 05:47:59 AM

Bluebird owners have had a few fire problems replacing the double wall muffler with a single wall, I am happy you told Jim I stayed out of it

as i know the series 40 (DT466) can reach EGT in excess of 1100 degrees under a load

Lostranger · May 13, 2015, 06:47:56 AM

I could easily wrap this muffler with header wrap. Would that be a good idea? What is a diffuser?

Jim

luvrbus · May 13, 2015, 07:34:56 AM

Blanket insulation is the best if Mike (Lowtide) didn't take it all I may have enough left I can send you for shipping to wrap your system I'll check and see

Lostranger · May 13, 2015, 07:46:10 AM

Thanks, Clifford.

Lostranger · May 13, 2015, 04:23:24 PM

I realize that what I'm about to report is in no way scientific or definitive, but I find it interesting. Had the bus on the interstate today for the first time since the muffler swap. Ten miles at 65 mph. Engine up to temp the entire way.

When I arrived at the tire shop, I immediately went back to the access panel beside the muffler. It's the closest thing to the muffler in any direction. Used palm of my hand to feel this panel from top to bottom. It was barely warm to touch. The original muffler got this panel much warmer to touch, but only on the lower half.

When I got back home, I did the same test again and also opened the rear hatch so I could feel the inside of the access panel between the muffler and the side. Same story. Barely warm to touch.

I need an IF temp gun anyway, and I'll try to get one soon, but so far, I see no indication that excess heat from the new muffler will be a problem.

Jim

P.S. The coolant temp seemed to run a few degrees lower than it did with the old muffler, but I can't be sure without further observation. Ambient was about 90 degrees F.