Home » Public Forums » GMCnet » muffler and placement
| muffler and placement [message #159583] |
Tue, 07 February 2012 19:37  |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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Well the body and paint work is finally finished on the WarPig. Rear suspension rebuilt(with new Sullybilt plates of course). Bogie pin and bushing kit(Applied). Rebuilt house windows with powder coated frames and new rubber(Alex Sirum for all window hardware). Rebuilt high efficiency dimpled core radiator(Seattle Radiator). New transmission lines. New roof vent covers and bathroom fan assembly(Alex Sirum). New led clearance lights(Alex Sirum). Stainless reproduction T handle latch assemblies for hoods and rear compartments(Alex Sirum). Led tail lamp bulbs(Alex Sirum). Patterson distributor with Howell E.F.I. and EBL <not yet installed>(Applied).
Next on the list will be replacement of the decrepit exhaust system and install bung for o2 sensor. Engine is a fairly fresh 455 with headers of unknown make. Currently the headers dump into a large resonator type thing under the house floor directly behind the cock pit step then dumping into one 3" pipe which runs through the cross members and out the back of the coach(passenger side). I have read on here that the "ideal" set up is one muffler toward the rear of the coach. I have very little room toward the rear due to placement of black and grey water tanks then further back, the hitch. I had a friend from a mechanical/exhaust business nearby stop by and look under the coach to see if he would be able to hook me up. He was in agreement with me that insufficient space exists in the rear for a muffler and was concerned about placing a two into one muffler where the resonator type thing is due to the extreme heat from being so close to the engine(his initial thought was to use a Camaro style muffler which would work well perpendicular to pipes coming off the headers but seemed worried about frequent replacement due to heat). So, who can suggest options or maybe links to some photos of systems which have been successful??
Thanks!
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: muffler and placement [message #159588 is a reply to message #159583] |
Tue, 07 February 2012 20:04  |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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| sgltrac wrote on Tue, 07 February 2012 19:37 |
Well the body and paint work is finally finished on the WarPig. Rear suspension rebuilt(with new Sullybilt plates of course). Bogie pin and bushing kit(Applied). Rebuilt house windows with powder coated frames and new rubber(Alex Sirum for all window hardware). Rebuilt high efficiency dimpled core radiator(Seattle Radiator). New transmission lines. New roof vent covers and bathroom fan assembly(Alex Sirum). New led clearance lights(Alex Sirum). Stainless reproduction T handle latch assemblies for hoods and rear compartments(Alex Sirum). Led tail lamp bulbs(Alex Sirum). Patterson distributor with Howell E.F.I. and EBL <not yet installed>(Applied).
Next on the list will be replacement of the decrepit exhaust system and install bung for o2 sensor. Engine is a fairly fresh 455 with headers of unknown make. Currently the headers dump into a large resonator type thing under the house floor directly behind the cock pit step then dumping into one 3" pipe which runs through the cross members and out the back of the coach(passenger side). I have read on here that the "ideal" set up is one muffler toward the rear of the coach. I have very little room toward the rear due to placement of black and grey water tanks then further back, the hitch. I had a friend from a mechanical/exhaust business nearby stop by and look under the coach to see if he would be able to hook me up. He was in agreement with me that insufficient space exists in the rear for a muffler and was concerned about placing a two into one muffler where the resonator type thing is due to the extreme heat from being so close to the engine(his initial thought was to use a Camaro style muffler which would work well perpendicular to pipes coming off the headers but seemed worried about frequent replacement due to heat). So, who can suggest options or maybe links to some photos of systems which have been successful??
Thanks!
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FWIW, this is what I did on our 78 Royale with Grey and Black water tanks.
http://www.gmcmhphotos.com/photos/showgallery.php?cat=3604
I kinda built the system myself, but if I had it to do over, I'd just buy the kit from Jimmy K and be done with it. JMHO
Larry 
78 Royale w/500 Caddy
Menomonie, WI.
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| Re: muffler and placement [message #159592 is a reply to message #159583] |
Tue, 07 February 2012 20:55 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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Todd,
Here is one version of a single front muffler... I believe Miguel has a shop do something similar for him.
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4690
Dennis
| sgltrac wrote on Tue, 07 February 2012 19:37 |
Well the body and paint work is finally finished on the WarPig. Rear suspension rebuilt(with new Sullybilt plates of course). Bogie pin and bushing kit(Applied). Rebuilt house windows with powder coated frames and new rubber(Alex Sirum for all window hardware). Rebuilt high efficiency dimpled core radiator(Seattle Radiator). New transmission lines. New roof vent covers and bathroom fan assembly(Alex Sirum). New led clearance lights(Alex Sirum). Stainless reproduction T handle latch assemblies for hoods and rear compartments(Alex Sirum). Led tail lamp bulbs(Alex Sirum). Patterson distributor with Howell E.F.I. and EBL <not yet installed>(Applied).
Next on the list will be replacement of the decrepit exhaust system and install bung for o2 sensor. Engine is a fairly fresh 455 with headers of unknown make. Currently the headers dump into a large resonator type thing under the house floor directly behind the cock pit step then dumping into one 3" pipe which runs through the cross members and out the back of the coach(passenger side). I have read on here that the "ideal" set up is one muffler toward the rear of the coach. I have very little room toward the rear due to placement of black and grey water tanks then further back, the hitch. I had a friend from a mechanical/exhaust business nearby stop by and look under the coach to see if he would be able to hook me up. He was in agreement with me that insufficient space exists in the rear for a muffler and was concerned about placing a two into one muffler where the resonator type thing is due to the extreme heat from being so close to the engine(his initial thought was to use a Camaro style muffler which would work well perpendicular to pipes coming off the headers but seemed worried about frequent replacement due to heat). So, who can suggest options or maybe links to some photos of systems which have been successful??
Thanks!
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: muffler and placement [message #159597 is a reply to message #159583] |
Tue, 07 February 2012 21:51 |
gbarrow2
Messages: 765
Registered: February 2004
Location: Lake Almanor, Ca./ Red Bl...
Karma: 3
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Senior Member |
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Sully,
Call Miguel at MGM-GMC 909-229-7508.
His muffler shop installs a single, flat, rectangular, 2 in 1 out muffler aft of the cock pit and continues with 3" pipe out the end. He has done many many over the years including my 76 Palm Beach. Relatively inexpensive, easy install.
He can tell you what to use and your exhaust shop can do it for you.
Much easier than the rear single muffler. I've been running mine behind Thorley headers for 60,000 plus miles with no issues.
Gene Barrow
Lake Almanor, Ca.
1976 Palm Beach
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| Re: muffler and placement [message #159598 is a reply to message #159583] |
Tue, 07 February 2012 21:52 |
GeorgeRud
Messages: 1380
Registered: February 2007
Location: Chicago, IL
Karma: 0
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I have JimK's dual muffler system running off headers in my coach, and have been quite happy with it. With each muffler coming off of one of the headers, then dumping into a Y fitting, it fits nicely into the area under the floor.
The pipe then swings to the passenger side of the coach and dumps out behind the rear wheels.
It was an easy project at home with Jimk's kit.
George Rudawsky
Chicago, IL
75 Palm Beach
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| Re: muffler and placement [message #159604 is a reply to message #159583] |
Wed, 08 February 2012 01:42 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Emery Stora has a Royale. 1978 I believe. He was the first one, to my knowledge, to go with the single rear muffler. If he does not post here, then contact him. I copied what Emery did on my 1976 Palm Beach. Jim K. sells the fully system all the way to the rear. I did not buy Jim's kit because I already had the 3" exhaust. It would have saved me a lot of time had I bought the parts I needed from Jim.
Contact Emery for advice and then Jim K. for the parts or the full kit as required.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: muffler and placement [message #159617 is a reply to message #159583] |
Wed, 08 February 2012 08:08 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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I tried the hush power muffler before trying the flowmaster 70.
The hush power is loud.
The flowmaster has a rumble to it, but is,'t too bad. sounds tough while the hushpower sounded cheap. If anyone want it, it's theirs for shipping!
It's a tight squeeze to get the muffler in the rear, but definitly worth it. It's the right way. really quiets down the coach inside.
The advantage of doing it myself is the main tube is one piece.
lot of running around buying parts tho.
But what else do I have to do on weekends?
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: [GMCnet] muffler and placement [message #159623 is a reply to message #159622] |
Wed, 08 February 2012 10:08 |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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Senior Member |
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Forgot to say that I later bought the rear outlet from Jim Kanomata because he has the bends just right to get around the back of the body and beneath the bumper.
Emery Stora
On Feb 8, 2012, at 9:06 AM, Emery Stora wrote:
> Actually I have a 1977 Kingsley.
>
> There were at least two others that had a rear muffler but I am the first to put it in line with the tail pipe along the frame.
> I also believe that I was the first to use the Flomaster 70 muffler.
> It has a rumble at idle but when the engine revs up there are internal reflectors that cancel out the sound waves so while driving it is relatively quiet.
>
> The others used quite a bit of bends in tubing to get the muffler mounted under the rear in the area of the trailer hitch.
>
> Jim K. asked me permission to duplicate my setup and he sells a kit.
>
> My writeup can be seen at: http://www.gmcmhphotos.com/photos/showgallery.php?cat=3123
>
> Emery Stora
>
> On Feb 8, 2012, at 12:42 AM, Ken Burton wrote:
>
>>
>>
>> Emery Stora has a Royale. 1978 I believe. He was the first one, to my knowledge, to go with the single rear muffler. If he does not post here, then contact him. I copied what Emery did on my 1976 Palm Beach. Jim K. sells the fully system all the way to the rear. I did not buy Jim's kit because I already had the 3" exhaust. It would have saved me a lot of time had I bought the parts I needed from Jim.
>>
>> Contact Emery for advice and then Jim K. for the parts or the full kit as required.
>> --
>> Ken Burton - N9KB
>> 76 Palm Beach
>> Hebron, Indiana
>> _______________________________________________
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>
> Emery Stora
> 77 Kingsley
> Santa Fe, NM
>
>
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Emery Stora
77 Kingsley
Santa Fe, NM
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| Re: muffler and placement [message #159628 is a reply to message #159583] |
Wed, 08 February 2012 12:04 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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Thanks to all who replied. It seems that there are two camps of thought on muffler placement, front and rear. There also seem to be single muffler and dual muffler groups.
I spoke with Miguel moments ago and he is adamant about single muffler for this application due past problems with one side plugging(was it passenger??) and forcing exhaust through the crossover which we all know is a bad thing. I cannot fit a suitable muffler in the rear of my coach without substantial modifications to the frame,muffler or both and there is a ton of room for a muffler in the original location. Although Keith's mod looks interesting I do not have any extra time to perform open muffler surgery. Emery's install looks really good as well but he has much more clearance inboard of the frame than I due to the placement of my waste tanks.
I mentioned the noise issue stated by Larry to Miguel and he thought that Larry must have had one of the smaller "short" versions of the SpinTech and that the larger version which he recommends is the quietest muffler he has been able to find for our coaches. Quieter than the flowmaster 70 "by a lot".
So I am waiting for Miguel to MMS me a photo of the muffler he is suggesting and will go from there. I will take photos of the install
Emery, I see you put the oxygen sensor in one side of the exhaust before the Y. Is this the ideal placement for good readings(one half of the motor) or would install down stream of the Y be better???
Thanks
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: muffler and placement [message #159632 is a reply to message #159628] |
Wed, 08 February 2012 12:47 |
PETEinLongBeach
Messages: 90
Registered: June 2007
Location: Long Beach, CA
Karma: 0
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I am also dealing with the eventual replacement of the original mufflers on my coach. Externally they appear quite intact, the running temperatures are about the same on each side, however due to the possibility of internal degradation and resulting backpressure issues, I want to proactively replace them.
Since the coach is very low mileage and original, I want to keep the system in its original configuation and exhaust sound. Which new mufflers would be most compatible with my original system? Should they be welded-in, or can I get away with the original-style clamp assemblies?
Pete Smay
Long Beach, CA
1977 Kingsley
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| Re: [GMCnet] muffler and placement [message #159633 is a reply to message #159631] |
Wed, 08 February 2012 12:48 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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| emerystora wrote on Wed, 08 February 2012 12:34 |
Sully
The way that the intake manifold crosses from one side to the other means that the fuel from both injectors is going to pistons on the left and on the right of the engine. So, taking a O2 reading on one side of the exhaust means that I am really getting both "sides" of the engine. I think that you will find that most people hook up their TBI system this way.
The farther you get from the engine block the more that you might need a heated O2 sensor. I have always used one.
Emery Stora
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My O2 sensor is just after the header.
it's too hot there, keeps over heating, so I'll have to move it back a ways.
BTW, I really didn't want to cut down the muffler, but it was the second one I had paid for, and wasn't about to go 3 for 3
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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