Restrictions from mufflers

08Monster · Jun 11, 2019

Does anyone have any real world data backing up what they gained/lost by adding or removing a muffler to one of these pickups. I'm just wondering if I am living in fairy tale land thinking I should have a muffler on mine.

It's a 2014, 363sxe, dual fuelers, MPD piping kit, etc.

It has 5in exhaust and the drone when towing after the sxe swap was unbelievably unbearable. So I threw on a 48in donaldson muffler, it's a big pig.

My mileage has always been ****, and EGTs seem higher than others with my comparable setup, and just overall just seems to run hotter than it should.

Doesn't feel like a loss of power, it's an absolute animal and is a blast to drive, just wondering if I'm leaving a ton of mileage and heat loss on the table by running this muffler?

Thanks in advance.

Sent from my XT1585 using Tapatalk

Jonnydime · Jun 11, 2019

Compounds are the best muffler. Does your muffler have a diffuser or it it straight through?

08Monster · Jun 11, 2019

Jonnydime said:
Compounds are the best muffler. Does your muffler have a diffuser or it it straight through?

I wish I could afford a 4k muffler right now. Haha

It's got a diffuser of sorts. It's got slots cut in the side, and in the center it crushes down to nothing to force it through the packing in the sides.

Sent from my XT1585 using Tapatalk

08Monster · Jun 11, 2019

Like this.

Sent from my XT1585 using Tapatalk

Jonnydime · Jun 11, 2019

All the big truck mufflers I have ran were straight through with no diffuser.

08Monster · Jun 11, 2019

Jonnydime said:
All the big truck mufflers I have ran were straight through with no diffuser.

These are the ones we ran on semis when I worked at CAT.

Sent from my XT1585 using Tapatalk

Sterling6.7 · Jun 11, 2019

That seems like it would be pretty restrictive. I put on a 42” and it was straight through and the inside of the pipe kinda resembled a cheese grater. It is a lot quieter, but still louder than stock.

lincolnlocker · Jun 12, 2019

I wish i ran an egt gauge. It might be due to others doing what i ended up doing on comparable rigs that didnt show anything to be concerned about on a dyno run heat wise but i put a resonator in front of a 40" Donaldson and going down the road it is quiet as a stock setup and all you hear is the turbo whistle when accelerating. At idle or mall crawl speeds it is still a little louder with a nice rumble. My muffler is basically a straight through with cheese grader looking holes but there is a section cut out of the center that is completely open. Probably 8 inches or so.

I would think that the style that 08monster put on would be more restrictive due to the design but it is the style what goes on big tucks. But with that said, there are a gazillion lil holes for it to go through.

Did you notice a egt change when adding it?

Any sort of turbulence in the exhaust stream is considered a restriction in my book but if it isnt a noticeable restriction and the end result is how you wanted it then rock on!

live life full throttle

08Monster · Jun 12, 2019

lincolnlocker said:
I wish i ran an egt gauge. It might be due to others doing what i ended up doing on comparable rigs that didnt show anything to be concerned about on a dyno run heat wise but i put a resonator in front of a 40" Donaldson and going down the road it is quiet as a stock setup and all you hear is the turbo whistle when accelerating. At idle or mall crawl speeds it is still a little louder with a nice rumble. My muffler is basically a straight through with cheese grader looking holes but there is a section cut out of the center that is completely open. Probably 8 inches or so.

I would think that the style that 08monster put on would be more restrictive due to the design but it is the style what goes on big tucks. But with that said, there are a gazillion lil holes for it to go through.

Did you notice a egt change when adding it?

Any sort of turbulence in the exhaust stream is considered a restriction in my book but if it isnt a noticeable restriction and the end result is how you wanted it then rock on!

live life full throttle

I wish I would have paid attention when I put it on, but I didn't ever take note of EGTs before and after. Until recently when I'm pulling and it's fairly warm out, I'm running about 1000 degrees constant on the flat doing 72 in 6th. That being said, I can drop to 5th and go to 750 degrees, but than my mileage is like 6mpg.

I can pull a hill and it only gets to about 11-1150 for EGTs so it's not like I'm in the danger zone yet. Just hotter than I would like and the mileage is awful. Pulling 7k at 72 I'm only getting about 8mpg. Might as well run a 6.2 gasser.

Sent from my XT1585 using Tapatalk

lincolnlocker · Jun 12, 2019

08Monster said:
I wish I would have paid attention when I put it on, but I didn't ever take note of EGTs before and after. Until recently when I'm pulling and it's fairly warm out, I'm running about 1000 degrees constant on the flat doing 72 in 6th. That being said, I can drop to 5th and go to 750 degrees, but than my mileage is like 6mpg.

I can pull a hill and it only gets to about 11-1150 for EGTs so it's not like I'm in the danger zone yet. Just hotter than I would like and the mileage is awful. Pulling 7k at 72 I'm only getting about 8mpg. Might as well run a 6.2 gasser.

Sent from my XT1585 using Tapatalk

Have you ever pulled the same load prior to now?

live life full throttle

08Monster · Jun 12, 2019

lincolnlocker said:
Have you ever pulled the same load prior to now?

live life full throttle

Yeah over a year ago, and I just can't remember what the EGTs were like before. Mileage was definitely better if I remember right. It's awesome how quiet it is, but damn it's gotta be what's making this ole girl run so warm and mileage so bad. I can only get 14 on the highway. Stock tires, stock height, not even leveled.

Sent from my XT1585 using Tapatalk

lincolnlocker · Jun 12, 2019

08Monster said:
Yeah over a year ago, and I just can't remember what the EGTs were like before. Mileage was definitely better if I remember right. It's awesome how quiet it is, but damn it's gotta be what's making this ole girl run so warm and mileage so bad. I can only get 14 on the highway. Stock tires, stock height, not even leveled.

Sent from my XT1585 using Tapatalk

Sounds to me like a boost leak. Try a different muffler or go back to straight pipe and see how it does. Do you have a back pressure gauge?

live life full throttle

08Monster · Jun 12, 2019

lincolnlocker said:
Sounds to me like a boost leak. Try a different muffler or go back to straight pipe and see how it does. Do you have a back pressure gauge?

live life full throttle

I can't hear a boost leak at all, and I'll make 40+psi when I lay into it.

No EBP gauge, the MPD budget kit doesn't have a provision for it. I might pull my passenger side pipe and weld in a bung. I have lots of extra sensors from 15+ swaps anyway.

Sent from my XT1585 using Tapatalk

lincolnlocker · Jun 12, 2019

08Monster said:
I can't hear a boost leak at all, and I'll make 40+psi when I lay into it.

No EBP gauge, the MPD budget kit doesn't have a provision for it. I might pull my passenger side pipe and weld in a bung. I have lots of extra sensors from 15+ swaps anyway.

Sent from my XT1585 using Tapatalk

You wont hear a boost leak. But id definitely go back to straight pipe and check egts after.

A minor boost leak at light throttle will add to the egt and drop mpg.. Just because it is still running strong up top with 40+ psi doesn't mean it doesn't hinder it at light throttle while cruising.

Im guessing it is the muffler being that is the only thing you changed correct?

With all the crap i have done to my old dually with a 38r on it, i could tell it had a boost leak just by egt and boost reading.

Make a boost leak tester or swap in a straight pipe.

live life full throttle

farm boy · Jun 12, 2019

May be apples to oranges since I'm running a VGT but...
I run a Jones Turbine 5050XL by itself on my 5" exhaust. Sounds good and no drone in the cab even when towing heavy. Not stock sounding but not loud and annoying either.

Cruising empty 800-850 EGT
Cruising loaded 1000ish EGT

Driving 70 the lie-o-meter reads 16-17mpg and my girl is on the heavy side with a flatbed, tools, 3" lift and 295's.

Pulling my camper (14k) I only get 8mpg or so running 75-80.

Good Luck!

08Monster · Jun 13, 2019

farm boy said:
May be apples to oranges since I'm running a VGT but...
I run a Jones Turbine 5050XL by itself on my 5" exhaust. Sounds good and no drone in the cab even when towing heavy. Not stock sounding but not loud and annoying either.

Cruising empty 800-850 EGT
Cruising loaded 1000ish EGT

Driving 70 the lie-o-meter reads 16-17mpg and my girl is on the heavy side with a flatbed, tools, 3" lift and 295's.

Pulling my camper (14k) I only get 8mpg or so running 75-80.

Good Luck!