Re: Resonator and muffler replacement Reply #50 – April 15, 2012, 08:52:56 pm Well, as few miles as I put on, not sure this is worthwhile, but I needed a project! Note: There's a lot of difference in the different models but here is what I learned so far on mine.1. Taking the side panel off is pretty easy. I cut the top trim at the joint rather than take off the whole length. It was an easy job with a dremel cut off wheel. The biggest problem I had was the two screws on the underside of the panel that stabilize the radiator there (I don't know what this radiator is for). Allen head screws, size 5 I think. One side broke loose, the other side I used Mr Dremel again to square the head so I could get a vise grip on it. The panel on the right side does go behind the back piece about 6 inches, but just pulls out forward. Most of the fasteners were badly rusted and several were not holding anything. Also the caulking did not present any problem, the panel just pulled loose from it.2. To get the muffler out, I messed around trying to get the clamps loose with no luck. As it turned out, all I needed to do was put a support under the muffler, cut the two bolts that hold the clamps around the muffler. The whole works then just dropped down, separating itself where the top clamp hooks on to the solid pipe that comes from the turbo. Your results may vary if it doesn't want to separate there. Quote Selected
Re: Resonator and muffler replacement Reply #51 – April 15, 2012, 10:06:45 pm Interesting, you muffler looks different than mine did. Mine was squat and round. Quote Selected
Re: Resonator and muffler replacement Reply #52 – April 15, 2012, 10:22:37 pm Gayland, good for you to get into this. See how easy it is to work with the panel off? The rad' is for the a/c (it is on mine) and you may have a dryer attached to it. Good time to change this too if you are having any problems with the dash air. The pressure has to be released on the R134a. If the right end of panel was attatched the same as mine there is a strip of alum' moulding that the screws going thru' the 2 pieces act as a clamp to hold the panel and end cap together, you may want to clean it up real good and caulk it on the inside of panel prior to putting the panel in place to close up. Align the screw holes on the strip and let sit overnight. As John S said yours is so different than mine too, as it was a squat canister, 4" in and 5" out. Good luck with the rest and enjoy the resultsJohn H Quote Selected
Re: Resonator and muffler replacement Reply #53 – April 15, 2012, 11:49:59 pm Quote from: John S – April 15, 2012, 10:06:45 pmInteresting, you muffler looks different than mine did. Mine was squat and round.That looks just like the muffler on our 1997 U295.Gayland, thanks for the good pictures and description. Quote Selected
Re: Resonator and muffler replacement Reply #54 – April 16, 2012, 12:14:33 am My batteries aren't in this area so maybe that's what makes them different. I've seen estimates of these things weighing up to 100 lbs, but I doubt that this whole setup was 30 lbs. Quote Selected
Re: Resonator and muffler replacement Reply #55 – April 16, 2012, 03:10:29 am Interesting! Your rear panel and AC condenser setup looks just like ours, but the muffler is tiny, compared to the trash-can sized one I took off. I bet replacing that muffler with a resonator will net you some significant added power! Quote Selected
Re: Resonator and muffler replacement Reply #56 – April 16, 2012, 10:47:52 am Yes, I saw the picture of two of you lugging yours out. Most of the pictures I've seen of the area have a big black plastic item (air intake?) in the area my muffler sat. Mine doesn't have that. Did you stay with 4" throughout, or were did you convert to 5"? Quote Selected
Re: Resonator and muffler replacement Reply #57 – April 16, 2012, 12:49:39 pm On mine (like Dave's) was 4" in to muffler and 5" out so I stayed 4" from Turbo and after the flex from it I converted up to 5" by way of a coupling (custom made to suit) to go to Res which was 5" and on out. Our mufflers were quite restrictive in design, yours looks more of a flow thru one.John Quote Selected
Re: Resonator and muffler replacement Reply #58 – April 16, 2012, 11:53:12 pm And I did the same - 4" flex to 4"->5" to 5" resonator and 5" to the tailpipe. Quote Selected
Re: Resonator and muffler replacement Reply #59 – April 17, 2012, 07:57:12 am I was looking at mine yesterday and idly wondering if it might be possible to sweep the flex down and around from turbo, directly into resonator...maybe moving resonator back a bit if necessary. Those 90's and 45's are restrictive in their own right. Has anyone considered doing this? Quote Selected
Re: Resonator and muffler replacement Reply #60 – April 17, 2012, 09:06:52 am The exhaust could be rerouted directly out thru the left side of coach reducing the restriction even further and saving money too. Dave M Quote Selected
Re: Resonator and muffler replacement Reply #61 – April 17, 2012, 10:33:59 am What happens if we install a straight pipe and do not include the resonator? I expect it is a bit louder. Has anyone tried it?While we were traveling on Interstate highways yesterday, sometimes I would hear what sounded like the engine making more noise than usual. It was always that pickup truck in the left lane. They were often louder that our coach before they were even with the engine in our coach! I don't want to emulate those vehicles. Quote Selected
Re: Resonator and muffler replacement Reply #62 – April 17, 2012, 12:13:09 pm Chuck, I do not see the 45's and 90's as being as big a restriction as more footage of flex. If you look at the inside of flex, because of it's nature there are many "ribs" to allow it to change shape that untill they fill up with soot and carbon are more restrictive than a smooth elbow. You can, by "shaping" the flex right maybe get away with just a 45!!!JD, to answer your question of not using a resonator--try it!! I also have a feeling that changing the shape (ie instead of cutting the tailpipe end square-try a curved shape) may change the sound of the exhaust by altering the sound waves on exit!!Any scientists/engineers on board to figure that one out??John H Quote Selected
Re: Resonator and muffler replacement Reply #63 – April 17, 2012, 10:28:34 pm I did the sweep with 4" flex into a 4 to 5 increaser into a 5" turn down about 36" long,,,,bout 2 years ago (20k miles) quicker spool,,less heat..noticeable power increase,,little increase in noise... Quote Selected
Re: Resonator and muffler replacement Reply #64 – April 17, 2012, 11:11:59 pm Straight piped mine.. 4'' all the way out 2 my FT tip. Big diff in power and my egt runs around 200 to 300* cooler as per my dash gage. But the trade off is the engine noise.. I can not tell up front but if I open the window while driving under a overpass it's LOUD,,most of it sounds like the turbo spooling up and down.. I have a Dodge 6.7 Cummins diesel that's fixing to roll 200k and I straight piped it a long time ago, Never hurt anything Quote Selected
Re: Resonator and muffler replacement Reply #65 – April 18, 2012, 02:48:14 am Yes, the resonator takes the harshness away, leaves the straight pipe effect with zero restriction.I found the effect using a 8V-92, straight pipe was too harsh, with resonator, just right without the harshness.Cave M Quote Selected
Re: Resonator and muffler replacement Reply #66 – April 18, 2012, 08:54:23 am Thinking back to the hot rod days, a rule of thumb is that one short 90 bend equals the restriction of 25 feet of straight pipe. While not exact, that's a pretty well accepted number among exhaust tuners. Exactly how this translates into backpressure is anyone's guess. A few other design considerations:The perfect after turbo exhaust system for a diesel has zero restrictions giving the biggest pressure differential across the pump (turbo). Non turbo engines function best with a tuned exhaust with some backpressure which helps scavenge exhaust gases from the cylinders. Here's the Donaldson site with hardware info, calculators, and flow rates for pretty much every diesel engine. http://www.donaldson.com/en/exhaust/support/datalibrary/061237.pdfAccording to their charts, my 6C 300 hp Cummins will flow 2140 CFM at full bore at 3000 rpm. A straight pipe will flow approx 115 cfm per square inch of internal diameter with minimal restrictions.So, 2140 CFM/115 = 18.6 square inches of circular area needed for inside of exhaust pipe. A 4" pipe has 12.56, a 5" pipe has 19". These numbers are for minimal backpressure. Interestingly enough, looking at what looks to be the OEM Donaldson muffler presently installed, and the flow ratings for it, I'm showing that just the muffler is creating more than 3"Hg backpressure. I'm pretty surprised to see that 4" pipe is marginal, would have thought it was plenty. Based on these numbers, you guys sensing a power increase from the changeout are most definitely not imagining it. I'm going to go for less than 1"Hg backpressure. Looks like it will be 5" pipe, if I can do it without 90 ells, will do so. Quote Selected
Re: Resonator and muffler replacement Reply #67 – April 19, 2012, 09:59:24 pm Thanks Chuck, that was very informative. I do feel much more power and it is noticeable and you can see it on the silverleaf as well. I do not hear the resonator at all unless I am running next to a wall. If I am and it is close and high then I hear a low roar. I have a different sound at idle but not unpleasant and it runs so much better up the hills it is a shame FT will not figure out how to do this to all of the coaches. Quote Selected
Re: Resonator and muffler replacement Reply #68 – April 20, 2012, 10:44:38 am J.D I am running with a straight pipe mine is quiter inside the coach a little more noise outside. Quote Selected
Re: Resonator and muffler replacement Reply #69 – April 20, 2012, 12:04:41 pm Quote from: Dave M – April 17, 2012, 09:06:52 amThe exhaust could be rerouted directly out thru the left side of coach reducing the restriction even further and saving money too. Dave MThat got me to thinking back. A few years ago heading west from San Antonio in my Cummins powered pickup at a pretty good clip I started around a good sized coach. Apparently he wasn't having any of it because he hit the go pedal and absolutely left me in the dust. In addition, the driver had no fear of the law either as I could hang behind him but no way could I pass. I did notice it had a side exhaust, a big one. Very impressive. That was before my interest in motorhomes so I didn't note the make. It was a fiberglass body, not a conversion. Quote Selected
Re: Resonator and muffler replacement Reply #70 – April 25, 2012, 07:34:29 am I kept 50 mph up cumberland gap on I 68 and that was great. Out west on I 90 and in Montana and WY I never got below 60 on any grade and that one time I did, was because a truck was in front of me and was going slowly up the grade. I pulled over after the three cars passed and accelerated past him. Now, what I want to know is why there an be no cars around for 50 miles plus and right when you want to move over you have to wait for them to pass. Quote Selected
Re: Resonator and muffler replacement Reply #71 – April 25, 2012, 08:32:04 am Quote Now, what I want to know is why there are no cars around for 50 miles plus and right when you want to move over you have to wait for them to pass.The answer is simple...Murphy's Law of hill climbing and passing... Quote Selected
Re: Resonator and muffler replacement Reply #72 – April 25, 2012, 11:33:22 am The beauty of the ISM 450 or 500 with the resonator is that you can pickup and pass when the lane clears up. Ever been in that situation, lane clears and you can not pull out and pass ? That is not a joyful thought for me. My thoughts run to mo power. Happy thoughtsDave M Quote Selected
Re: Resonator and muffler replacement Reply #73 – April 25, 2012, 02:31:18 pm With the resonator conversion, it looks like the exhaust is closer to the rubber boot on what I assume is the air intake. Anyone have any problem with heat deterioration? Thanks Quote Selected
Re: Resonator and muffler replacement Reply #74 – April 25, 2012, 02:41:55 pm Quote from: Dave M – April 25, 2012, 11:33:22 amThe beauty of the ISM 450 or 500 with the resonator is that you can pickup and pass when the lane clears up. Ever been in that situation, lane clears and you can not pull out and pass ? That is not a joyful thought for me. My thoughts run to mo power. Happy thoughtsDave MWhat exact parts are needed to change my 97 450M? Quote Selected
Topic: Resonator and muffler replacement