MACKS Posted March 27, 2009 Share Posted March 27, 2009 Doe's anyone here have any experience with dynaflex mufflers,I'd like to hear your thoughts on the sound reduction of these mufflers as compared to a straight pipe,I'm running a straight single 5 inch pipe on my 96 cll only because there is not enough room for a regular muffler between the cab and the dump body and I'm not real crazy about installing anything under to cab.Thanks in advance for any help. Quote Link to comment https://www.bigmacktrucks.com/topic/8806-dynaflex-muffler/ Share on other sites More sharing options...
mackcl96 Posted March 27, 2009 Share Posted March 27, 2009 Doe's anyone here have any experience with dynaflex mufflers,I'd like to hear your thoughts on the sound reduction of these mufflers as compared to a straight pipe,I'm running a straight single 5 inch pipe on my 96 cll only because there is not enough room for a regular muffler between the cab and the dump body and I'm not real crazy about installing anything under to cab.Thanks in advance for any help.Heard them on Cat's they were 6" and helped, gave them a deeper tone Quote Thanks for hearing me out.You can have the soap box now---------JIM Link to comment https://www.bigmacktrucks.com/topic/8806-dynaflex-muffler/#findComment-32674 Share on other sites More sharing options...
Dlock13 Posted March 28, 2009 Share Posted March 28, 2009 We installed the GrandRock QP internal mufflers in our 6" exhaust. It has a good sound but not too loud. Quote Link to comment https://www.bigmacktrucks.com/topic/8806-dynaflex-muffler/#findComment-32704 Share on other sites More sharing options...
MACKS Posted March 28, 2009 Author Share Posted March 28, 2009 We installed the GrandRock QP internal mufflers in our 6" exhaust. It has a good sound but not too loud.Thanks for the info,but what is a qp internal muffler,never heard of them,do they add a lot of back pressure,thats what Im looking for not to loud.Also could you tell me how much they cost.Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/8806-dynaflex-muffler/#findComment-32706 Share on other sites More sharing options...
mackdaddy1911a1 Posted March 28, 2009 Share Posted March 28, 2009 Thanks for the info,but what is a qp internal muffler,never heard of them,do they add a lot of back pressure,thats what Im looking for not to loud.Also could you tell me how much they cost.ThanksI hear commercials on my XM radio everyday and customers stories on the trucking shows when guys call in about the Q.P. mufflers on their trucks. They claim not only do they get better fuel milage but that the "Quiet Performance" mufflers are quieter than O.E.M. mufflers. I would like to have a set of them myself if the frieght ever picks back up. Do a little research online before you buy. I understand that they can even custom build anything even for old trucks. Good Luck. Quote THE GREATEST NAME IN TRUCKS MACK TRUCKS Link to comment https://www.bigmacktrucks.com/topic/8806-dynaflex-muffler/#findComment-32725 Share on other sites More sharing options...
jzack Posted March 28, 2009 Share Posted March 28, 2009 Thanks for the info,but what is a qp internal muffler,never heard of them,do they add a lot of back pressure,thats what Im looking for not to loud.Also could you tell me how much they cost.ThanksI ordered a QPM (Quiet Performence Muffler) for my truck a while back but haven"t had a chance to install it yet. SUPPOSEDLY, they will relieve backpressure yet remain just as quiet as stock. They also claim to lower EGT's and get you better fuel mileage. In fact they guarranty better mileage or your money back. I have heard that your Jake is quite a bit louder with a QPM though. It looks like a big auger system stuffed into your stack. It is patented so there may be something to it.....The mfr. is Grand Rock, I ordered mine through Berube's.Jeff Quote Link to comment https://www.bigmacktrucks.com/topic/8806-dynaflex-muffler/#findComment-32726 Share on other sites More sharing options...
MACKS Posted March 28, 2009 Author Share Posted March 28, 2009 I did a search on line and read up on them a little,they state on there web site that you can only use them if you have duel exhaust so I guess back pressure is a problem with single exhaust. Quote Link to comment https://www.bigmacktrucks.com/topic/8806-dynaflex-muffler/#findComment-32739 Share on other sites More sharing options...
jzack Posted March 28, 2009 Share Posted March 28, 2009 I did a search on line and read up on them a little,they state on there web site that you can only use them if you have duel exhaust so I guess back pressure is a problem with single exhaust.I never heard the duel exhaust thing, could you provide a link to that page? If we are looking at the same product I actually read that they decrease your back pressure. This is why they have been popular on school buses that have that extremely long, restrictive pipe that runs the length of the bus body. Quote Link to comment https://www.bigmacktrucks.com/topic/8806-dynaflex-muffler/#findComment-32741 Share on other sites More sharing options...
mackcl96 Posted March 29, 2009 Share Posted March 29, 2009 I did a search on line and read up on them a little,they state on there web site that you can only use them if you have duel exhaust so I guess back pressure is a problem with single exhaust.Glad you did the research a Friend tried them on duel strait 5" and was to much back pressure (he is turned up)if you call Grandrock they will tell you the minimum pipe size for your HP you may have to go up to 6" duels to use QP Quote Thanks for hearing me out.You can have the soap box now---------JIM Link to comment https://www.bigmacktrucks.com/topic/8806-dynaflex-muffler/#findComment-32748 Share on other sites More sharing options...
Rob Posted March 29, 2009 Share Posted March 29, 2009 Damned metal munchers got to my exhaust. Guess I'll need to get a new one. Thing is, you couldn't see this behind the burn guard. The pipes were readily apparent.This is a Donaldson muffler. Are there rules that you have to run a muffler at all? My R795 did not have a muffler and it sounds nice but is not objectionable through five inch stacks.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/8806-dynaflex-muffler/#findComment-32760 Share on other sites More sharing options...
MACKS Posted March 29, 2009 Author Share Posted March 29, 2009 Rob, you can go with straight pipes if you want,I love the look of the crome straight pipes but driving all day the noise gets to be annoying especially in a dump truck with all the stop and go and accelerating thru the gears thats why i was looking at the dynaflex it's got that nice clean look of a straight pipe,but I can't find any info on the actual sound reduction,I might have to take a chance and order one and hope for the best. Quote Link to comment https://www.bigmacktrucks.com/topic/8806-dynaflex-muffler/#findComment-32782 Share on other sites More sharing options...
Rob Posted March 29, 2009 Share Posted March 29, 2009 Rob, you can go with straight pipes if you want,I love the look of the crome straight pipes but driving all day the noise gets to be annoying especially in a dump truck with all the stop and go and accelerating thru the gears thats why i was looking at the dynaflex it's got that nice clean look of a straight pipe,but I can't find any info on the actual sound reduction,I might have to take a chance and order one and hope for the best.Hi Macks, I can certainly agree that a dump truck would be annoying if noisey. My R795 truck has dual stacks with turnouts about a foot above the cab roof. I think the engine makes more operational noise than is emmited from the exhaust but I've never "worked" the truck. I also say this unknowing as to the true exhaust tone because I've always driven, and not heard the truck drive off. I'm not one that is into a lot of "flash" and chrome. A nice single chrome stack 18-24" out of the top of the muffler is fine with me and a stainless burn guard is about all that is required.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/8806-dynaflex-muffler/#findComment-32784 Share on other sites More sharing options...
jzack Posted March 29, 2009 Share Posted March 29, 2009 I did a search on line and read up on them a little,they state on there web site that you can only use them if you have duel exhaust so I guess back pressure is a problem with single exhaust.Just looked at Grand Rock's site again and seen the "duel exhaust only" disclaimer. I ordered their single exhaust but I suppose it works differently because it is not a straight pipe but an OEM style muffler. I think its curious how a product that claims better MPG would also increase back pressure????? Good luck in your search for a quiet straight stack MACKS. Quote Link to comment https://www.bigmacktrucks.com/topic/8806-dynaflex-muffler/#findComment-32786 Share on other sites More sharing options...
MACKS Posted March 29, 2009 Author Share Posted March 29, 2009 Thanks to everyone for all the input,I'm pretty sure I,m gonna go with the dynaflex rather then try to stick something in the pipe,I know the dynaflex will fit in the limited space I have and it will quiet it down a little,maybe just enough to make driving the truck more enjoyable while still having a nice sound to it.I still have a few more things to do to the truck before work starts but when I get to the exhaust I'll post back here with a few pictures and let you all know what I think of the dynaflex.Rob I agree the muffler with a nice guard and chrome top stack looks great,I just don't have room to fit the muffler. Quote Link to comment https://www.bigmacktrucks.com/topic/8806-dynaflex-muffler/#findComment-32799 Share on other sites More sharing options...
mackcl96 Posted March 30, 2009 Share Posted March 30, 2009 Thanks to everyone for all the input,I'm pretty sure I,m gonna go with the dynaflex rather then try to stick something in the pipe,I know the dynaflex will fit in the limited space I have and it will quiet it down a little,maybe just enough to make driving the truck more enjoyable while still having a nice sound to it.I still have a few more things to do to the truck before work starts but when I get to the exhaust I'll post back here with a few pictures and let you all know what I think of the dynaflex.Rob I agree the muffler with a nice guard and chrome top stack looks great,I just don't have room to fit the muffler.If you want a muffler use ser#4370 it has the the brackets turned really close and more to the side of the cab It is so close the grab handle is in the cab Quote Thanks for hearing me out.You can have the soap box now---------JIM Link to comment https://www.bigmacktrucks.com/topic/8806-dynaflex-muffler/#findComment-32810 Share on other sites More sharing options...
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