New MCI MC-5C muffler today.

[bevans6]

Well, the job du jour was to install the muffler that I picked up yesterday.  I picked a Donaldson M120131, which is inlet/outlet on the same end to suit the MCI pattern, 26" long which is 2" longer than the stock muffler, and a lot smaller in cross section.  The MCI muffler is about 22" wide and 15" tall, while the Donaldson is 15" wide and 10" tall (all of their oval mufflers with in/out on the same end are that cross-section).  It weighs probably half or less what the MCI muffler does.  The M120131 is the lowest restriction muffler they have that would fit, it is 2913 CFM and lowest attenuation as well, to suit the turbo engine I am running.  The install was pretty painless, the straps that hold the stock muffler in are stainless steel so were in almost perfect shape, the bolts are into stainless steel so they undid, all I had to do was modify the straps to suit the way smaller OD of the new muffler.  I kind of mounted it at an angle to get the inlet into the right position so my downtube would fit without any changes.  The new muffler is far less restrictive than the old one, you can tell just by looking.  It's basically a 5" diameter tube about 20" long full of 1/4" holes open at the end into a cap and exactly the same on the outlet.  The stock muffler inlet tube was about a 15" long tube with the same holes but fully closed at the end - everything had to go through the tiny holes.  Sound level, frankly, sounds exactly the same to me.  The turbo obviously does a good job of quieting thing down at an idle, anyway, so most of the sound is the engine and not the exhaust.  Sorry, no pics.  I was done before I thought of that.  I thought this might be useful to the other MCI guys, since I suspect they all use exactly the same muffler.  I might take a few pic's tomorrow.  I had to lose my stack though.  It's a 4" stack and the new outlet is 5"...  I will get a simple chrome turn-out for it.

Brian

Pic of my old stack.  Maybe I will cut it down and put it on my smoker (not the bus, the one that smokes pork butts, bacon, turkeys, etc...)

Brian

[wg4t50]

Brian,
Looks great if you want the vertical exhaust, being a true red neck, I would be thinking maybe with the turbo engibe, using a 5" short resonator hang vertical from turbo with elbow at bottom, just a thought.
Not real familiar with the 5 series, but being a lover of power, I tend to take some short cuts.

I had the MC7, with the 8V-92, just ran out the driver side.
Anyway I do like your thinking.
Cheers
Dave M

[bevans6]

There is about 11" of space vertically between the elbow out of the turbo and the elbow out of the engine bay - but that's lots of room for a straight pipe...    I think, given that I need to pass an annual DOT, that this will work very well indeed.

Brian

[RJ]

Brian -

IMHO, your 5C will look better w/o the exhaust stack, it's a bus, not a truck!

Also, if you can put a 45^o on the outlet such that it exits under the bumper corner, it will be a LOT easier to monitor the exhaust if/when you encounter Rocky Top climbs.

Altho the rubber flap hanging off the bumper helps keep crud off your toad, it does tend to trap heated air coming off the engine.  GM installed a full-width flap behind the rear axle to create a low-pressure area under the engine while cruising, thus helping to cool the compartment.  Consider the same?

FWIW & HTH. . .

[bevans6]

Rear flap is long gone...  didn't work, got recycled a couple of years ago.  I am a big fan of high exhaust outlets, but I kind of agree that they look a little redneck on a bus unless you can hide them.  I was trying to keep oil off the towed car, didn't work, but after you spend $700 for the shiny bits you seem to keep putting them back on...

Brian

[TomC]

That is exactly the muffler I'm running on my turbo and air to air intercooled 8V-71. It puts out a really nice tone when pulling a hill and just about zero back pressure. You look inside the muffler and all you see is one baffle separating the right from the left side. I like that muffler so much, I bought one also for my Caterpillar 3406B truck conversion. Good choice! Good Luck, TomC

[Stormcloud]

Brian:

I was about to put a full-width flap across the back of my -7 for the same reason.
Maybe I will have to buy a car cover.....

Mark