Community Forums

Robar · 02-14-2013, 06:09 AM

I am considering purchasing a 2001 American Coach with an 8.3L Cummins ISC 330 hp and found that the muffler has a hole in the bottom of it and exhaust is escaping. The exhaust pipe looks good otherwise.

Has anyone replaced one of these? Can the rest of the system be saved or does it all have to go, and what did it cost? Should I consider an aftermarket muffler or go with the OEM version?

topdownman · 02-14-2013, 06:19 AM

I'd definitely look at the Aeroturbine unit. I replaced the one on my ISB. All I replaced was the elbow from the turbo, muffler and a new piece of pipe out the back. Your installation may vary but I think it cost me around $300 for all of it. Sounds nice too.

dennis45 · 02-14-2013, 06:28 AM

Quote:

Originally Posted by Robar

I am considering purchasing a 2001 American Coach with an 8.3L Cummins ISC 330 hp and found that the muffler has a hole in the bottom of it and exhaust is escaping. The exhaust pipe looks good otherwise.

Has anyone replaced one of these? Can the rest of the system be saved or does it all have to go, and what did it cost? Should I consider an aftermarket muffler or go with the OEM version?

You can replace the muffler only. There is an OEM muffler that the chassis manufacture Spartan or Freightliner would likely be able to supply. Requires no modification.
Or, you can get an aftermarket that will be different dimensions and will require some modification to the mounting bracket. It is said that it improves fuel economy and HP but I personally don't buy it.

As far as the rest of the system, have a close look at it. When I did mine, the pipe off the Turbo was rusted out and the Exhaust Brake Valve was seized up. The hole in the muffler was just the obvious.
All the exhaust parts were less than $600. I just cleaned and repaired the Exhaust Valve while I had it apart.

R2Home · 02-14-2013, 01:31 PM

Replaced the muffler in our MH last summer. No one here in AK had one so I ordered one from Summit racing, along with new band clamps. Lots of room to work and the change out was OK. Had very good service from Summit and the price was in the ball park of what I expected.
I was able to just replace the muffler as the rest of the piping was good. Expect to get dirty though with lots of rust flakes getting on you.

D M · 02-14-2013, 01:56 PM

Hi Robar I replaced my muffler last year with a aero muffler that I bought on eBay it was easy to install and looks good and sounds great.

dennis45 · 02-14-2013, 04:26 PM

Quote:

Originally Posted by D M

Hi Robar I replaced my muffler last year with a aero muffler that I bought on eBay it was easy to install and looks good and sounds great.

Nice install, looks great. Did it improve HP and or Fuel Mileage? As stated above, I have been told this happens but I don't buy it.

D M · 02-14-2013, 04:42 PM

Dennis I think it helped on both hp and mpg hard to tell. The last trip I took to the ORE coast pulling a car I got 9.75 mpg but the speed is 55 mph. But it sounds good. The wife even likes the sound it sounds more Manley. And the chicks dig it!

dennis45 · 02-14-2013, 04:47 PM

Quote:

Originally Posted by D M

Dennis I think it helped on both hp and mpg hard to tell. The last trip I took to the ORE coast pulling a car I got 9.75 mpg but the speed is 55 mph. But it sounds good. The wife even likes the sound it sounds more Manley. And the chicks dig it!

Right,
Well, better fuel mileage is always a good thing but having to beat the chicks off the back ladder when we stop would be a little overwhelming.

WILDEBILL308 · 02-17-2013, 02:30 PM

I changed out my stock muffler with one from Banks that I bought from Summit Racing on line.
http://www.summitracing.com/parts/gbe-53801
The installation was straight forward as it was the same length as stock. Make sure your exhaust pipe from the turbo is 4 inch as some of the older units came with a 3 in exhaust an upgrade to 4 in is available. The good thing is I don’t think I will ever have to replace the muffler again. The bad news is when I had the muffler out I spent about 5 hours cleaning and painting the area that is hidden by the muffler. The back of the battery racks and any thing that looked like it needed paint. I haven’t been on a long trip so I don’t know if my mileage has improved. I am getting 8.5 towing a Honda Civic on a tow dolly.
Bill

zmotorsports · 03-01-2013, 10:06 AM

When I purchased our 2003 Dynasty with the ISL400 engine in 2007, I noticed that the previous owner must have drug at some point in time and broke the small hanger that connected the 90 degree elbow from the downpipe to the muffler inlet. While I was under the coach fabricating a new hanger I got to looking at this huge, ugly and heavy muffler that Monaco (Roadmaster) installed on the coach. I started noticing all of the hear tracers on the muffler and thought how restrictive it looked.

I had several friends/relatives that had diesel coaches and they kept telling me to remove the muffler and run a straight pipe. I am not a fan of that as one, I don't think you get the gain that people think, and two, I don't like the loud droning sound that is produced without a muffler.

I did some research and ended up purchasing and installing a Dynomax 5" inlet/outlet muffler that I obtained from Summit Racing for around $100.00. Installation took a bit because while I was installing the muffler I also decided to snug the exhaust up a little tighter to the chassis and change the exit of the exhaust from the side of the coach. I ended up fabricating a completely new exhaust system from the turbo to the exit.

I love the sound it has and have gotten several compliments as I have pulled through campgrounds as to the exhaust sound, yet while driving down the road it is not noticeable.

Mike.

Robar · 04-20-2013, 05:24 AM

I also went with the Banks muffler from Summit even though it is made for the 5.9 Cummins and I have an 8.3L ISC.

http://www.summitracing.com/parts/gbe-53801

The installation was pretty easy as the new piece is the same length and has the same inlet/outlet as the stock one. I had to do something with the hangers but that is not a big deal. It looks great.

Haven't had it out yet but was wondering if anyone else had tried this on the larger engine. I couldn't get Summit to state that it was ok to use it, but I checked with someone from performance truck parts and they said that all of these aftermarket mufflers are straight through, so he couldn't see how they wouldn't work on a larger displacement engine. He was right, you can look right through the Banks muffler.

Genset · 04-20-2013, 07:29 PM

Having worked larger engines, such as truck etc all mu working life, when I purchased my new to me 2001 Foretravel 5 years ago, it has the ISM450 engine, I replaced the Cowl muffler with a Walker Resonator, and bingo, right off, it was very clear that it was much more power, as the turbo can spin up faster with so much less back pressure etc..
You can buy the fancy and costly chromed jobers, but me I just want it to run sweet. Now I have also up graded the ISM from the 450 hp @ 1450 torque, to the newer 500 hp @ 1550 torque. yes, it jumps just dandy, as for fuel burn, I am certain it would get better fuel mileage, however it is so hard to keep my foot out of it, that the fuel mileage is the same, it just runs quicker.
Dave M