Replace catalytic convertors

[fnawesome15]

I have a 2004 Workhorse Chassis. Has anyone used the replacement convertors on Workhorse Parts or Ultra RV Products? It looks like a relatively straight forward bolt on installation. Thanks.

[John.W]

I would make sure any aftermarket converters you purchase will be compatable with your factory emission system. Some aftermarket cats do not play nice with factory equipment. Perhaps someone on the forum can make a recommendation based on personal experience. You might also consider the old trick of using sparkplug extensions to space the downstream O2 sensor out of the exhaust flow resulting in a more favorable reading. I have read this can work if the factory cats are performing marginally but throwing a code. Google this idea for a better explanation of how this idea works. I have no direct experience doing this only having read about it.

[Arch Hoagland]

Why are you replacing them?

[Daveinet]

I trust Ultra RV to know what they are doing. I'm running their Ultrapower on my W22 chassis, with the trans shift modifications. Since they have been into the programing of the ECU, they will know what is compatible with your engine. The is a pretty strong history here of folk using their products and be very satisfied with them. These are one of the good guys in the biz.

[Tom17]

I also have 2004 W22 chassis. The following is information I collected regarding finding replacement cats when mine were stolen. While I was at it I also replaced all flange gaskets, donuts, mufflers and installed an H-pipe in front of the cats. That was over a year ago and it has been great. Also running the Ultrapower ECM and TCM.

Catalytic Converter Selection
2004 Workhorse W22

Vehicles over 14,000 pounds were not typically tested. Instead, emission standards were tested and assigned to a family of engines.

The EPA Emission Standards for Heavy Duty Engines (HDE) were set at:
From 1987 to 2007 HC (g/bhp-hr) for > 14,000 lbs is 1.9
From 1987 to 2004 CO (g/bhp-hr) for >14,000 lbs is 37.1
NOx + NMHC (g/bhp-hr)
1987 = 10.6
1988 - 1990 = 6.0
1991 - 1997 = 5.0
1998 - 2004 = 4.0

Per the emissions label the engine is in the 4GMXH08.1503 family.

The 2004 CARB/EPA emission standards for the 4GMXH08.1503 engine family are:
NOx+NMHC CO
Standard CARB/EPA 1.5/4.0 37.1/37.1
Certified Level 0.6 3.9

The emissions equipment listed on the emissions label for this engine family are: SFI 2TWC 2HO2S (sequential fuel injection, 2 three way converters in parallel, and 2 oxygen sensors (one on each side before the converter). The single oxygen sensor for each cylinder bank is used by the computer to control fuel mixture. There is no sensor after the converter to monitor its performance. A 3 way catalytic converter (TWC) oxidizes carbon monoxide and hydrocarbons, and reduces nitrogen oxides.

Typically OBD1 applied for vehicles years 1988 to 1995 while OBD2 was used in 1996+ vehicles.
There was no EPA OBD requirement for HDEs > 14,000 GVW prior to 2010.

From the 2005 Workhorse Owner’s manual for P and W Series Chassis (page 1-66):
“Your vehicle is equipped with a computer which monitors operation of the fuel, ignition and emission control systems.

This system is called On-Board Diagnostics-First Generation, (OBD I for Federal) and On Board
Diagnostics Second Generation (OBD II for California less than 14,000 lb. GVWR), and is intended to assure that emissions are at acceptable levels for the life of the vehicle, helping to produce a cleaner environment.”

Note that it says OBD2 for less than 14,000, 2004 W22 has no post catalytic converter O2 sensor and is over 14,000 hence not really a full implementation of OBD2. For Federal EPA emissions purposes, it is OBD1. However, it should be noted that per EPA there was no requirement for even OBD1 for HDEs in 2004.
The emissions label does not say OBD2 compliant or even OBD1. It only has the engine family and says it meets CARB and EPA requirements.

CA, CO, ME, and NY require a CARB compliant converter. So, if registered there, you have no choice but to purchase and install a CARB converter.
From Walker Exhaust web site regarding replacement converters in all but CA, CO, ME, and NY:
“In all other states that are not mentioned above, EPA-compliant aftermarket catalytic converters may be used for all repairs regardless of whether the vehicle was certified as legal for sale in the state of California. Select the appropriate catalytic converter for your vehicle based on the recommendations in the published Walker application data or catalog.”

From Magnaflow regarding Standard Load EPA Pre-OBDII converters:
“Designed to meet EPA emissions standards, this OBDI-compliant converter is offered in a universal-fit configuration and is available for both gasoline and diesel applications. MagnaFlow makes this catalytic converter with a traditional clam shell design as well as a more compact, spun-body design.”

The converter selected should be sized properly for both engine displacement and GVW.
The W22 has 8.1 liter engine and a GVWR of 22,000 pounds. For purposes of towing a vehicle, the CGVWR is 26,000 pounds.

Magnaflow 95509 catalytic converter:
95509 displacement: The converter is listed for use in a 1995 7.4 liter equipped vehicle. Therefore, two of them in parallel should be capable of handling 14.8 liters.
95509 GVW: The converter is rated for a vehicle up to 13,000 pounds GVW. Two in parallel would be capable of handling 26,000 pounds.
Conclusion: The Magnaflow 95509 catalytic converter will meet the requirements to install on a 2004 Workhorse W22 equipped motorhome under Federal EPA standards.

[fnawesome15]

Cats were cut off and stolen. The ones I mentioned are oem. It is the cat plus a section of pipe, flanged on each end. Looks to me that it's just remove the old and bolt in the new. Just wanted to make sure I wasn't overlooking something. O2 sensor is before this section of the exhaust.

[Tom17]

Yep, that's the part. I considered them when I was looking for replacements. But at about $1700 each I decided to research what was a suitable replacement that met Federal standards. The Magnaflow 95509 cats are less that $500 each. The $2400 difference for two of 'em buys a lot of gas for that thirsty 8.1 big block.

[CamJam1]

Magaflow 94009 is what I put on my W22 when my converters were stolen two years ago. 10k miles on them since then and no problems whatsoever. They're currently $138 each on Amazon. I did the installation myself. Fortunately the thieves did a clean cut on both pipes and new converters bolted straight up without any further cutting or welding. Just be sure to buy the right clamps for the 3" pipe.

Insurance paid me based on cost of buying the original Workhorse replacements, so I made close to $2k by doing it myself.

[fnawesome15]

Originally Posted by CamJam1

Magaflow 94009 is what I put on my W22 when my converters were stolen two years ago. 10k miles on them since then and no problems whatsoever. They're currently $138 each on Amazon. I did the installation myself. Fortunately the thieves did a clean cut on both pipes and new converters bolted straight up without any further cutting or welding. Just be sure to buy the right clamps for the 3" pipe.

Insurance paid me based on cost of buying the original Workhorse replacements, so I made close to $2k by doing it myself.

So, do the Magnaflows have a 3" inside diameter that you could just slip over the existing pipe? Or did you use a different connection?

[CamJam1]

Originally Posted by fnawesome15

So, do the Magnaflows have a 3" inside diameter that you could just slip over the existing pipe? Or did you use a different connection?

Yes, they were a slip fit. All I needed was muffler clamps. Would be another story of course if the thieves cut off too much of your exhaust pipes.

[Tom17]

The cats you installed are only rated for 6000 GVW so two would be 12000. They may be fine and they may not. Under extended heavy loading they may overheat and fail then again they may not, depends on where and how you drive. However, they do not meet the Federal requirements for sizing of the cats based on engine displacement and vehicle GVW. Hope they continue to work for you.

[CamJam1]

Originally Posted by Tom17

The cats you installed are only rated for 6000 GVW so two would be 12000. They may be fine and they may not. Under extended heavy loading they may overheat and fail then again they may not, depends on where and how you drive. However, they do not meet the Federal requirements for sizing of the cats based on engine displacement and vehicle GVW. Hope they continue to work for you.

I'm pretty sure we looked into this before buying, but now I do see 6,000 GVW quoted at JEGS and Summit, but I also see 8,500 and 15,000 at other sites. Unfortunately, the link to specifications on Magnaflow's site-- which would be straight from the horse's mouth-- doesn't work, at least on my computer.
In any case, since installing them we've been over both Wolf Creek Pass and Vail Pass, and Arizona to Oregon and back twice and they're holding up fine. If in fact the GVW rating is only 6,000, I guess I screwed up, but I'm pretty sure I looked into this previously.

If in fact 6,000 is the true GVW rating of the 94009, I would certainly opt for the 95509 mentioned above, even though twice the price.

[George Schweikle]

Another connection scheme is to use band clamps. Look at any 18 wheeler truck exhaust for an example. No pipe overlap is necessary, and a band clamp will even connect slightly different size pipes. Just butt the two ends together and wrap the clamp around the joint.

Another advantage of using band clamps, is the capacity to disconnect if needed; which is almost impossible if a traditional muffler clamp has tightened and distorted the joint.

https://www.amazon.com/Evilenergy-Jo.../dp/B076J5HSNJ

Originally Posted by fnawesome15

So, do the Magnaflows have a 3" inside diameter that you could just slip over the existing pipe? Or did you use a different connection?

[Larry JV]

Tom, did you look into simply not replacing the stolen cats and go with a straight piece of pipe? In my area emissions test is no longer a requirement. I might consider no cats as long as it does not affect the engine's performance.