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New Exhaust System Plans


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My OEM muffler is starting to rust out.  Rather than put it back the way it is I am considering building up a "weed burner" so that I can take advantage of the space gained rear of the cab.  Looking at materials available it appears to me that a 6' section of 5" stainless steel flex pipe should work well from the turbo outlet to an inside mounting position for a new OEM style muffler pretty much equally distant from the fuel tank and drive shaft on the passenger side.  I would use a couple of feet of the existing chrome stack as a tailpipe that points straight down at the ground (not out the side).  All clamps will be stainless steel band clamps.  I will, of course, need to make my own pipe hangers and supports.   Charlie has mentioned to me on several occasions a restriction similar to a washer with a 2" opening welded in behind the turbo.  I do not know if my truck has the same.  It would seem that taking this out (if mine does indeed have it) would create better exhaust flow but at the expense of what?  EGR, exhaust brake, turbo spin-up????  I've never paid much attention to how others have plumbed their weed burners.  Any additional thoughts or ideas will be appreciated.

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I don't know the particulars on your truck, a guy I know with an older Pete 359 had an OE muffler with a restrictor  in the muffler.      There should be no detriment to a full flow exhaust with regard to engine braking or turbo spool up.    

The fella mentioned had issues with coolant temps in hot weather in city traffic, the engine stays at more consistent temps since the change.   



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17 hours ago, mr. cob said:

Howdy Randy,

The exhaust straight down could be nasty if it’s a dusty area, just something to think about.


I second this. My truck has a weed burner that points down. Two things, the dust and the right rear tire temps go high in slow traffic.  I do hope to change my setup eventually it's just not real high on my priority list right now.

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No regen on this truck. It is a 2004 D12D with EGR. I do agree that pointing the exhaust down could create a dust devil - might be better to just go straight back if I don't turn it.  My main problem with going out the side is my Volvo has the full fairing that covers the fuel tanks.  I would end up cutting a hole in the fairing and need to drop the exhaust system lower to the pavement.  Also more bends and band clamps.  I'll have to work on this.  Actually, the comments are now making me wonder if a weed burner is what I really want to do.  It could put more soot on the lower front of the fiver.  The other issue is the doughnut that Charlie reported finding inside his 2006 Volvo exhaust.  I am "assuming" I have the same restriction in mine. If anyone has experience with this thing, good or bad, I need to know.  I do remember reading something awhile back about the metal gasket used between the turbo and exhaust manifold was restricted so as to boost pressure in the exhaust for the EGR.  The suggestion was to enlarge the opening in the gasket if one had the turbo off and screw the EGR.  Doing so increased turbo performance.  If the doughnut is there for a similar reason I would think it needs to go.  I could be opening Pandora's Box with this project - you know how one thing leads to another.  The EGR system on this engine is working OK but failure of the valves or cooler can become very expensive.  The EGR delete kit from OTR remains in the back of my mind.  Ghee Wiz, all of this thinking started with a little rust hole appearing in the top of the stack muffler.  Maybe a glob of exhaust putty is all I need.  I think I feel a headache coming on.  Oh, BTW, I'm close to week 8 from my back surgery.  I feel good and am beginning to resume my normal activities.  The only problem is my muscles are weak from 3 months of inactivity and I have picked up a few pounds as well.

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Randy,   I purchased a 2006 with 500K mile in 2010, and was disappointed with the MPG, so did the EGR delete, and at the same time, did the weed burner thing.  Ran a straight pipe (a few bends & turns) with a turn down @ about a 1/3 turn. Removed the donut still got 6 1/2 MPG, and no change in power. I think the slight turn really helps with the dust, we live in the country, and 3 miles off the payment.   After a year or so, I had to replace the cooler ($$).  So, I removed the plug, but retained the weed burner.  I'm 76 years old now, and can't hear so good, plus I had back surgery 12 weeks ago, soooo, I'm now in the process of reinstalling the stack.  I saved everything, muffler, brackets, etc., but everything seems much heavier than it did 9 years ago.  I hope after the reinstall I will be able to hear the "Top dog" better.  OH WAIT, is that a good thing??  BTW, I was surprised your 2004 had a EGR, I didn't think they had them until 05, or 06 at the cost of a mile or two MPG.  Good luck with your truck, and your back as well.    Dick T      

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3 hours ago, oletimer said:

BTW, I was surprised your 2004 had a EGR, I didn't think they had them until 05, or 06 at the cost of a mile or two MPG.   

EGR came with the EPA04 emission package engines, which, for most manufacturers, went into production in the fourth quarter of 2002, per a consent decree.  They can be found even in some late 2003 model year trucks.

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On 8/25/2019 at 11:55 AM, Big5er said:

Randy, I don't think OTR makes or sells that kit anymore.

I did not know that.  I Iooked at their web page and could find noting but the reset tools.  I wonder why it is not listed?  Did they get in trouble with the EPA?  I do know someone that bought one a couple of years back when they had a sale but has yet to install it.  Lucky guy - he is sitting on a gold mine.  I often wondered how the EGR Delete software was set up.  Many years ago I wanted to eliminate the O2 sensor on a car when I was doing autocross.  I bread-boarded up a little device using a 556 timer that would give the ECM random levels of low voltage to allow a richer fuel mixture without making the ECM go into limp mode.  From what I have read the same type of variable voltage readings are generated by the EGR on the Volvo.  If there is NO voltage variation to the ECM you get the fault PID and perhaps the derate.  Now, I want to know more and will shift my attention to exploring what the EGR sensor is doing.  I have a recording digital pocket o'scope with a SD card that I can use to capture the EGR data from the sensor over an hour or more of on the road mileage.  I don't know, but maybe I can put together a device that will fool the Volvo ECM into thinking the EGR is operating.  But, keep in mind I am sorta half-fast when it comes to such a project.  BTW - the exhaust system change project is now on hold.  I bought a can of ceramic exhaust putty at Autozone and patched up the current rust holes in the top of the muffler.  A few shots of silver high temp exhaust paint and  it looks like new.  It is still in the way of what I want to use the space for behind the cab but further changes are not imminent.  Thanks to everyone for their input.

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I was considering a weed burner setup awhile back (still have not done it yet) and Roger (Hewhoknowslittleshared with me what he did on his Volvo.

Picture link:

https://s42.photobucket.com/user/rogerjones218/library/Bed Build?page=1

Parts list:

(1) Donaldson muffler part number M120749

(1) 90 degree x15" inches long elbow #L590-1515A

(1) 45 degree X8 inches long elbow # L545-0808A

(3) band clamps # PF-5SS

(1) Curved chrome pipe #K5-18sbc


Mounting bracket for the muffler we made out of the old stack mounting bracket, welded them to the fairing mounts and made straps to hang the muffler.

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