Muffler vs. Full Exhaust

[Bulldogger]

My question is: Is there anything to be gained as far as lowering EGT's by just replacing the stock muffler with a high flow one vs. replacing the entire exhaust system? Somebody posted that their higher flow less restrictive muffler lowered EGT's by 100-200 degrees which also seems to be the claim of most complete muffler systems. Any help would be appreciated. Thanks Dave

[Paintdude]

I am starting to think the same way..Just replacing the muffler will be good enough..

[ski]

You have to ask yourself how much a 1/2" will do for flow when the downpipe is 3 ". If you change this then the restriction ( again 1/2 ") moves to the exhaust system.

The only problem I can see is if you change the muffler, what does this do with respect to tuning ? Some have complained about irritating resonance at certain speed/rpms. I myself am planning on changing only the muffler also, when I finish the research and find one built add to the stock system.

[Idle_Chatter]

I did a "mufflerectomy" on my truck. There's no doubt that a full exhaust system will flow better than what I've got, and actually would probably be about the same amount of work to install. I spent a lot of time cutting with a chain-type hand cutter, not only to make the two cuts to remove the stock muffler, but a cut on each end of the replacement muffler and one end of each of the adapters to get the package short enough to go between the hangers. I also had to expand both ends of the stock pipe at the cuts to make them round again, because they were bends and the factory bends are ovalled. Then there was fitting everything up and tack welding, dropping it back out and finish welding and then rehanging and reclamping the system. The free flowing muffler makes a huge difference over the factory muffler in the factory pipes. But the factory pipes are still 3-1/2" before and after the muffler and don't have the nice smooth mandrel bends of a full system. My job was done with about $250 worth of parts and a lot of work.

[hoot]

A true mufflerectomy is removing the muffler and welding in a straight pipe. :D

A little loud at times but I like it.

[MaxRock]

Hoot,

I'm having the age old battle of good vs. evil! Over Christmas break, I had made up my mind to straight pipe the truck, but the good exhaust fairy was saying "No it will make the truck to loud, it may upset the neighbors" and the evil exhaust fairy was saying "do it, screw the neighbors"!

Well, once again, good won out over evil. I've decided to install EGT and boost gauges before I make any mods, that way I will have some base line to judge the effect the mod has on the truck.

Maybe after the gauges...STRAIGHT PIPE!

MaxRock

[hoot]

When I straight piped mine, we cut the muffler off with a sawzall. We left some pipe on both ends of the muffler in case I wanted to weld it back on.

Needless to say, it's still in the crawlspace.

It's not loud under light loads. You can start it in the morning no problem. Has a mild rumble. The only time it's really loud is on hills and hammering it.

On the highway it's fine.

You can always change it easily if you don't like it.

[Toddster]

Mufflers resonate, it's just the nature of the beast....This is why companies like Flowmaster offer a choice of different mufflers with different resonance levels. Example....My 98 short bed regular cab 4x4....Gibson exhaust (fake duals) slight rumble around town, slight in cab resonance @ 70mph....Went to my buddies muffler shop, ran "true" duals from the cats, to dual flowmasters (the loud ones) to the dual Gibson tailpipes running strait out the back. Nicer rumble around town, Chinese water torture @ 70mph ! Back to the shop, cut off the flowmasters, clamped in 2 strait pipes in thier place....OBNOXIOUS around town, that thing would BLAT like a sick calf looking for momma ! But, cruising @ 70mph, only SLIGHTLY louder than the stock exhaust...Go figure....Warning ! Do NOT try this on your truck ! The combination of strait pipes, burning/squeeling rubber and smoke @ 2am is NOT your neighbors idea of an alarm clock ! :mad:

[Rebel_Horseman]

Hey Toddster, maybe that's why my neighbors didn't like me. Had a '96 with true duals and glasspacks that would set off car alarms without problem then when I bought my '01 Z with the 5.3 I put a straight pipe on it and WOW was that truck loud. The stop signs in my neighborhood looked like the starting line at a drag strip with all the burnouts, most of which were done about 2 a.m. after having a night on the town. :rolleyes: ;)

Reb [><]

[srubrn]

I replaced just my OEM muffler with one from Flo-Pro and I am happy with it. The shop here installed it for $150. The muffler was the most expensive part.

[ski]

The info here is good. I have to wonder for you you muffler replacement guys, sounds like the cost of the muffler plus install (or the amount of time for a quality install) would be close to replacing the whole thing. The cheaper exhausts start around 300 (aluminized, but not sure how big a deal this is in my mild climate) and go 600 to 800 for quality stainless. Does any one know how much effort is put into the design of the exhausts so to avoid the "drone" effect ?

[LarryM]

A local shop quoted me $375 to install a Dynafolw muffler. Another local shop put on a 4" Walker straight through muffler for $100! This same shop would have done a complete 4" system for $400. Obviously the Walker is not stainless, but in the areas I operate my truck, plain steel lasts 20 years so that is not a concern for me.

[afp]

Magnaflow offers both mufflers and full exhausts. The guy at Magnaflow told me 75% of the restriction was in the muffler, and the stock DMax pipes were pretty good. So I went with just the muffler. When I start towing, if my EGTs don't stay where they should, I'll install a larger exhaust system.

Blaine

[sixl]

Just go with the 4" it has a better sound and looks really cool :cool: I first cut just the muffler off then I heard 4" straight and had to have it temp. wise about 100 deg. diff.

[HK 3]

I have a 4.31 (90 HP) Juiced Duramax and have replace the stock muffler with a MagnaFlow galvinized 30" "catback" muffler. I have noticed the drop in EGT's of around 200 degrees. I pull a 6,500 lbs. Sundodwner horse trailer and a 6,500 lbs. boat up Parley's Canyon out of Salt Lake City to Park City over a 7,800 pass, which is a constant 8 to 9 mile grade from 5,200 feet to 7,800 feet. I can go over the top of the grade, easily at 85 MPH pulling these loads and have only seen a maximum 1200 on the EGT. Obviously, the 4" down pipe from the turbo back through the muffler would be nice, however, my experience suggests that if you are not hauling huge loads that the muffler switch out to a free flow "catback" type muffler is more than adequate on EGT's when engaged with a Juice and don't require the replacement of the entire exhaust system. With my Juice and have never used the tow/Haul mode and have continually used the 90 horse power setting. Additionally, I have never had a down shift in the Allison transmission going over this grade, however I am typically driving up the grade in the 75/80 mph range. Another thought, although the stainless steel mufflers come with lifetime guarantees, the standard galvinized steel muffler is more than adequate sells for 1/3 the cost and will last as long as you typically will own your truck.

[sixl]

Empty I Have got over 1200deg, I have the hot box but in level 2 I hit 1350 with 4"exh. :confused: and in level 4 I have got 1607deg not sustained but never the less hit them :eek:

[hoot]

I've seen 1600+ very rarely. Only mods are air filter/box, straight pipe and propane.

[ 02-03-2003: Message edited by: hoot ]</p>

[Paintdude]

Talked to a muffer shop guy(kid) today ,he said I needed to have a custom muffler because the engine needs the back pressure.. :rolleyes:

Guess I will call someone else who has a CLUE..

[Lone Eagle]

HK 3, Where did you get the Magnaflow and how much? Later! Lone Eagle

[afp]

My magnaflow was the 20" SS version. It required 3.5-4' adapters to make it work, and a slight tweak on the tail pipe to get evreything lined up right.

Blaine

[Paintdude]

I am going with a Jardine system.. smile.gif It is ordered..

[TSimpler]

straight piped mine today.

Sounds VERY GOOD

I also noticed the go pedal responded faster

Trent

[Paintdude]

I decided there is no capable exhaust shops around here..They just do not have a clue..One guy wanted 225 bucks to put on a muffler..

:rolleyes:

I can get Jardine-Pinnicle systems for 450 bucks inc shipping to you in the lower 48 states if anyone wants one..

[ 02-06-2003: Message edited by: Paintdude ]</p>

[Silver Bullet]

I went with the Dynomax. I ran me about $185 installed here in the Dallas area. I must say it sounds better JUICED. Couldn't justify the full 4" system for my useage. I have heard Kennedy 4", Banks 4", stock, and mine. They all sound very similar, but a little different. If I was going to spend the money on it based on sound alone I would go with the Banks. I am helping a friend install one this weekend...I hope it installs as easy as the Kennedy!

[Buck]

Kennedy's 4&gt;5" exhaust is the cats a$$. ;) tongue.gif Very happy :D :D :D

Sweeeet :cool:

[Mike O.]

PaintDude,
Same up here in Santa Fe - the muffler shops are either clueless or jerks when you start asking questions about their systmes/work. What did you decide to do?

[Paintdude]

I became a Jenkins-Pinnicle dealer and can have Matts systems drop shipped to customers..450bucks inc shipping.. paintdude1@yahoo.com ..I even sold one today..4in system with magnaflow muffler..

[TSimpler]

Mike O

I found a shop in Albuquerque that does a great job, Jim's 66 Muff on Central ave.

Did my straight pipe for me in about 25 min and cost $55

Trent