3" straight pipe exhaust modification... initial impressions.

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DRTDEVL

Active member
I had my exhaust guy build a custom, one-off exhaust yesterday... it took him several hours, and $500 later, I am a happy camper.

The original exhaust behind the OM647 was a 3" bell fitting on the down pipe that immediately necked down to 2.5", where it went to a flex pipe that reduced to 2.25"... and then through 2 cats, a muffler the size of a kitchen trash can, and then out the back.

Now it's a 3" bell, a 3" flex, and 3" straight pipe all the way through to a mandrel-bent 3" 45* angle tailpipe at the end. It is clamped together and has removable, color coded hangers in case I ever move somewhere that requires diesel emissions checks. He asked me to grab the down pipe off of my parts van to scavenge the bell fitting and hanger, along with making it easier to mock up a 3" replacement. The downpipe is made from stainless steel, while the rest is aluminized pipe. I'll probably give it a few days, and then clean it up and hit it with ceramic coating header paint all the way back in order to prevent any corrosion.

It kind of sounds like a deleted Cummins 6.7, only not nearly as loud. It will probably change a little more when I install the aluminum turbo resonator delete pipe and get the Green Diesel Engineering tune. My only worry thus far would be the placement of the O2 sensor bung... the sensor is about 1/8" farther out of the exhaust stream from stock. I am hoping this doesn't throw the van into confusion nor cause it to add too much fuel and kill the economy.

I'm tearing the van apart today for the 120,000 mile cooling service and the 60,000 transmission service, installing a 120a alternator, installing a power inverter, and several other smaller tasks, so it will be a couple weeks before I truly know how it runs and feels with the new exhaust. I only have Wednesdays totally off, and I don't think I will finish everything today, so it will be a week before its back on the road. I'll revisit this post with more driving impressions at tht point, and again in a month when the GDE tune is added.
 

Attachments

New Mexico Statutes - 66-3-844 — Mufflers; prevention of noise; emission control devices.

66-3-844. Mufflers; prevention of noise; emission control devices.

A. Every motor vehicle shall at all times be equipped with a muffler in good working order and in constant operation to prevent excessive or unusual noise, and no person shall use a muffler cutout, bypass or similar device upon a motor vehicle on a highway.
 

LS1K5

Member
I'm sure there's some law about removing the DPF also but I would totally do that if I wasn't in California!

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DRTDEVL

Active member
New Mexico Statutes - 66-3-844 — Mufflers; prevention of noise; emission control devices.

66-3-844. Mufflers; prevention of noise; emission control devices.

A. Every motor vehicle shall at all times be equipped with a muffler in good working order and in constant operation to prevent excessive or unusual noise, and no person shall use a muffler cutout, bypass or similar device upon a motor vehicle on a highway.
It's not loud at all... It makes just enough noise that you know something has been done, but it's still one of the quietest vehicles on my block.
 

lindenengineering

Well-known member
I'm sure there's some law about removing the DPF also but I would totally do that if I wasn't in California!

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For info it HAD a Cat on it, now eliminated.
Which is fine unless you try to register it in a state that requires an E test.
Then it will fail on a visual.
Dennis
 

Nautamaran

2004 140” HRC 2500 (Crewed)
... it's still one of the quietest vehicles on my block.
And THAT, dear friends, is perhaps why 66-3-844 was passed in the first place?

I'm not a big fan of the "loud pipes save lives" motorcycle crowd either...
or of anti-vaxers... though for different reasons.

-dave

(in fairness, 15 feet of crooked 3" pipe probably has enough fluid mass to provide a fair amount of damping while at idle, but I suspect you'll rattle somebody's fillings going down the freeway at 70+% LOD...)
 

LS1K5

Member
For info it HAD a Cat on it, now eliminated.

Which is fine unless you try to register it in a state that requires an E test.

Then it will fail on a visual.

Dennis
Thanks for the clarification, I'm fairly new to modern diesels and the difference between a cat and a DPF wasn't very clear to me. I wouldn't even own a diesel if it didn't have a cat on it, can't stand the exhaust smell! Probably from years of commercial fishing boat trips what's the smell of cigarettes, fish guts and diesel exhaust combined with rough seas[emoji2961]

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Nautamaran

2004 140” HRC 2500 (Crewed)
Mine has some sort of DPF because it doesn't smell like diesel exhaust.
Nope, just cleaner exhaust, which is the combined result of very high pressure fuel atomizing to improve combustion and reduce sooting, a Carbon Monoxide / Hydrocarbon-burning catalytic converter, and a NOx-reducing EGR system.

NO2 is that brown-coloured exhaust component that "smells like diesel exhaust".
It becomes Nitric Acid and contributes to ground-level ozone levels, which kills lakes and eats your lung tissue when you inhale it. That's why public health officials around the world have been enacting tighter NOx emission controls... big coal plants, oil furnaces, and vehicle emissions all continue to cut their NOx output.

So PLEASE leave your EGR and catalytic converter on your van so they can do their job...

The DEF/Bluetec urea-based catalytic system for scrubbing NOx out of the engine exhaust is required to meet the latest emission targets, but was never fitted to OM647 Sprinter engines.

OM647 engines never got the soot-filtering DPF systems either (nor the headache of failed "regeneration" cycles - my reason for choosing the T1N platform despite its age).

I spent quite a few years afloat, sleeping next to various Detroit Diesel 4-, 6-, and 8-71 Series two-stroke diesels... simple and dependable but their smell was indeed memorable.

-dave
 
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LS1K5

Member
Nope, just cleaner exhaust, which is the combined result of very high pressure fuel atomizing to improve combustion and reduce sooting, a Carbon Monoxide / Hydrocarbon-burning catalytic converter, and a NOx-reducing EGR system.



NO2 is that brown-coloured exhaust component that "smells like diesel exhaust".

It becomes Nitric Acid and contributes to ground-level ozone levels, which kills lakes and eats your lung tissue when you inhale it. That's why public health officials around the world have been enacting tighter NOx emission controls... big coal plants, oil furnaces, and vehicle emissions all continue to cut their NOx output.



So PLEASE leave your EGR and catalytic converter on your van so they can do their job...



The DEF/Bluetec urea-based catalytic system for scrubbing NOx out of the engine exhaust is required to meet the latest emission targets, but was never fitted to OM647 Sprinter engines.



OM647 engines never got the later soot-filtering DPF systems either (nor the headache of failed "regeneration" cycles - my reason for choosing the T1N platform despite its age).



-dave
Thanks, I love my t1n and would never run a straight pipe but larger diameter exhaust and possibly a more free-flowing cat would be nice. I also have a 2007 Duramax LBZ which has a cat and egr but none of the other crap, I plan on avoiding DEF and DPF as long as possible but I do love the turbo diesel.

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It's not loud at all... It makes just enough noise that you know something has been done, but it's still one of the quietest vehicles on my block.
New Mexico Statutes - 66-3-844 — Mufflers; prevention of noise; emission control devices.

66-3-844. Mufflers; prevention of noise; emission control devices.

A. Every motor vehicle shall at all times be equipped with a muffler in good working order and in constant operation to prevent excessive or unusual noise, and no person shall use a muffler cutout, bypass or similar device upon a motor vehicle on a highway.
:2cents:
 

Midwestdrifter

Engineer In Residence
The T1Ns turbo is well sized and spools quickly enough for my needs. Adding a slightly large exhaust will have slight improvements with throttle response at the middle RPMs. It will be louder though. Not crazy loud thankfully. The turbo does a good job of blocking most noise on its own. So a good sized resonator will do the trick, especially with a full body length exhaust. Generally speaking a 2 1/2" exhaust is good for about 230HP before you start seeing significant restriction.

Personally I would still install a universal diesel CAT. A 2.5" diesel specific unit is around 100$. It may not last 300k miles like the factory units, so slip joints may be a good idea.

Other than some very strict locations (some parts of California for example). The authorities don't care what you do to your muffler as long as its not loud enough to cause disruption. If you have ever heard an exhaust straight from the header, you know what I am talking about.
 
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Nautamaran

2004 140” HRC 2500 (Crewed)
"Disruptions" take many forms...

My grandparents had a place on a lake in British Columbia that I visited often during the summer months.
Once or twice a year, someone (usually with USA plates) would arrive with a jet-boat with a 350 or 454 fitted with straight header pipes.
They would generally get about 5 minutes before the RCMP patrol boat had them rowing back to the launch ramp... :whistle:

-dave
 
"Disruptions" take many forms...

My grandparents had a place on a lake in British Columbia that I visited often during the summer months.
Once or twice a year, someone (usually with USA plates) would arrive with a jet-boat with a 350 or 454 fitted with straight header pipes.
They would generally get about 5 minutes before the RCMP patrol boat had them rowing back to the launch ramp... :whistle:

-dave
Good. :thumbup:

Muffler-less Harley-Davidson "lifestyle enthusiasts" are a major nuisance too. I fully support citing/arresting/impound towing them to the fullest extent of the law. :thumbup:
 

Midwestdrifter

Engineer In Residence
For a while (~2000-2006) the Import performance crowd was the primary offender in my area. Over the last 5 years or so the number of "bro" trucks has increased significantly. Cheap bolt-on "performance" exhausts with no muffler are not very pleasant. The "cold air intakes" and K&N filters don't help either. The more flu$h folks drive the 1 ton trucks with diesels. Straight pipes with 6" flare tips, coal rolling with 8" lifts, wheels 6" outside the body, and low profile A/T tires. Its a brave new world...
 
For a while (~2000-2006) the Import performance crowd was the primary offender in my area.
I support enforcement of existing motor vehicle equipment laws on the fart-can enthusiasts.

Over the last 5 years or so the number of "bro" trucks has increased significantly. Cheap bolt-on "performance" exhausts with no muffler are not very pleasant. The "cold air intakes" and K&N filters don't help either. The more flu$h folks drive the 1 ton trucks with diesels. Straight pipes with 6" flare tips, coal rolling with 8" lifts, wheels 6" outside the body, and low profile A/T tires. Its a brave new world...
And I support enforcement of existing motor vehicle equipment laws on the micro-penis set also.
 

Nautamaran

2004 140” HRC 2500 (Crewed)
Happily that stuff doesn’t tend to get very far down the road up here, but I still have to navigate under the occasional RAM 3500 crew cab with a 10” lift kit... I’ll be VERY upset if one ever kills my family by running a red light and putting their bumper through the side window. I take a different approach: show us why you need to modify it and we’ll allow it for that purpose... but you can’t use your mud-buggy as a daily driver.
</rant>

-dave
 

Gabe Athouse

New member
"Disruptions" take many forms...

My grandparents had a place on a lake in British Columbia that I visited often during the summer months.
Once or twice a year, someone (usually with USA plates) would arrive with a jet-boat with a 350 or 454 fitted with straight header pipes.
They would generally get about 5 minutes before the RCMP patrol boat had them rowing back to the launch ramp... :whistle:

-dave
it seems like you’re comparing a straight piped sprinter with a OTH jetboat. That’s, well, I won’t say what because it will sound even more obnoxious than either one.
 

Gabe Athouse

New member
Happily that stuff doesn’t tend to get very far down the road up here, but I still have to navigate under the occasional RAM 3500 crew cab with a 10” lift kit... I’ll be VERY upset if one ever kills my family by running a red light and putting their bumper through the side window. I take a different approach: show us why you need to modify it and we’ll allow it for that purpose... but you can’t use your mud-buggy as a daily driver.
</rant>

-dave
Ah so you operate under the theory of “unless it’s allowed, it’s not allowed”. That’s a slippery slope my friend.
 
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