Community Forums

deSanford · 11-28-2011, 04:24 PM

I have a ISB 6.7 Cummings (Monaco Cayman by Navastar) one of the last of that series that doesn't use "cow piss" for the catalytic muffler. Can the muffler be removed (off road of course) and the engine computer not miss it? The muffler on my MH gets cleansed every so often automatically with HIGH heat. Other then that I don't know too much about it. Would like to put a straight pipe 4" instead of what is there.

Pusherman · 11-28-2011, 07:15 PM

No. If you do remove this system, you may be in violation of EPA laws clean air act. My understanding is that any engine built after 1/1/2007 has diesel treatment systems (DPF's for example) which cannot be altered.

(Some) Engines built after 1/1/2010 use a urea injection system to meet 2010 diesel emission requiremet systems. Cummins for example.

deSanford · 11-28-2011, 09:23 PM

Thanks I believe that I must have a DPF system. What is a DPF treatment system. So that system can't be "altered". Would the engine run without the DPF system? My Cummings was built after 1/1/2007 and before the UREA system.

CJScepter · 11-28-2011, 10:34 PM

I know of some that have removed the particulet filter on diesel pickups, they had to reprogarm the engine module and remove the unit, it made tremendous difference in power and mpg. Also..... the reason they do this is to stop the "washing" of the cylinders when it adds fuel for the "burn cycle" This has caused excess fuel in the oil pan as it washes by the rings. the result can be quarts to gallons of crankcase liquid, causing many engine failures in Ford Dodge and GM. Always watch your dipstick, keep engine serviced and if oil level grows,,, CHANGE THE OIL!
Now, those that removed the filter used a programer for the engine they had, don't know whats out there for yours.
John G

deSanford · 11-29-2011, 08:12 AM

Thank you CJScepter........any idea where one might go to possibly have this program done. I'm sure it would be where they have a computer etc for the ECM.. I might call "BANKS" and see if they know a shop that can handle this.

CJScepter · 11-29-2011, 10:21 AM

I sent you a PM

accumack · 11-29-2011, 10:53 AM

A. Federal Law
The federal tampering prohibition is contained in section 203(a)(3) of the Clean Air Act (Act), 42
U.S.C. 7522(a)(3). Section 203(a)(3)(A) of the Act prohibits any person from removing or rendering
inoperative any emission control device or element of design installed on or in a motor vehicle or motor
vehicle engine prior to its sale and delivery to an ultimate purchaser and prohibits any person from
knowingly removing or rendering inoperative any such device or element of design after such sale and
delivery, and the causing thereof. The maximum civil penalty for a violation of this section by a
manufacturer or dealer is $25,000; for any other person, $2,500. Section 203(a)(3)(B) of the Act
prohibits any person from manufacturing or selling, or offering to sell, or installing, any part or
component intended for use with, or as part of, any motor vehicle or motor vehicle engine where a
principal effect of the part or component is to bypass, defeat, or render inoperative any device or
element of design installed on or in a motor vehicle or motor vehicle engine, and where the person
knows or should know that such part or component is being offered for sale or is being installed for

such use. The maximum civil penalty for a violation of this section is $2,500.

Perry White · 11-29-2011, 11:09 AM

$2,500 if you do it $25,000 if dealer or Manu. I'd go for it.

sc3283 · 11-29-2011, 01:07 PM

Muffler is NOT an emissions control device.

Drifter · 11-29-2011, 01:24 PM

Muffler IS an emissions control device.

moisheh · 11-29-2011, 03:17 PM

Loits of misinformation. A DPF technically is not a muffler. It is a Diesel Particulate filter. Any added fuel does not go to the cylinders. There is a fuel line running to the DPF. When the system calls for a regen cycle fuel is injected into the DPF. Nowhere near the cylinders!!! I have never read in any truck mag( they have billions of miles of experience with DPF's) about cylinder washing. If this were the case we would all know about it. The coach mfr. cannot alter the DPF. It comes from the engine mfr. with a specific inlet pipe and that cannot be altered. Our Dynasty has that system and I would not fool with it. If you ever had a warranty problem that has anything to do with fuel delivery your warranty would be void. Why would anyone fool with a 2011 MH worth a bundle? I do not like the heat that is given off but in 32,000 miles I have only had 3 full regens. Your computer will record any changes you make.

deSanford · 11-29-2011, 03:44 PM

Well Moisheh is the most informed on this subject. CJScepter gave me a GREAT lead on how to get more power. He suggested I call Brazel's RV in Centrailia, Wa. They confirmed everything Moisheh said and told me about a TS Performance MP8 that plugs into the fuel CPU (or something) on the engine. It increases the HP and the Torque. I might be mistaken, but I think you dial in more HP and Torque when you would like it (passing trucks). Going up a hill the trucks pass me. Thanks for all the responses. P. S. I'm going to leave the DPF attached where it is.

deSanford · 11-29-2011, 08:17 PM

I forgot to ask has anyone tried the TS Performance MP8? If you haven't look it up on line and see what you think of it. Before I make any engine Mods I'm doing my due diligence.

CJScepter · 11-29-2011, 10:16 PM

In checking deSanford's Coach I see moisheh is right, it uses the "in stream injection" to the Particulate Filter, ie separate line and an injector probably just before the filter. Particulate Filters trap the soot diesels make, they have to clean themselves every so often. If the exhaust temp reaches 1100 degrees it pretty much takes care of it, thats why moisheh has had only 3 regens in over 30k miles. A heavy coach gets temp up pretty easy.
Now from 2007 to 2010 most diesel pickups used what they call "cylinder post injection" When needing to regen, it injects diesel (using present injectors) into the cylinder on both the compression stroke and exhaust stroke, sending the unburned fuel out the exhaust port to the Particulate Filter to be burned that way. The drawback is promoting fuel dilution of crankcase oil. As the fuel is injected on the exhaust stroke the fuel is able to pass by the piston rings and wash down the cylinder walls as well.
Good thing is I don't think any of our Larger coaches ever used post injection, but my diesel mechanic friend has seen broken rods,pistons and holes on blocks caused by this! He said those that ran the rig hard had no trouble, but some that putted around town and idled alot seemed to have more trouble.
Sorry I didn't check closer before I spoke.
John G.