Soot trap or cat?

[w6bauer]

I just removed my nearly new stock exhaust system on my 96 and am looking at what some call the soot trap and the inside looks an awful lot like a cat. I do have the f vin engine which is not supposed to come with a cat. I am wondering if the dealer I bought it from replaced the exhaust system with an s code style. How do I tell the difference just by looking at it?

The reason I ask is I will be trying to sell the old system and have no idea what, if any, the price difference would be for a cat vs a soot trap. Any help would be greatly appreciated! Just installed straight pipe for cheap and need to get rid of the nearly new (15,000 mi) old system, behind downpipe.

Thanks

Will

[Hubert]

Soot trap is just what diesel guys call it. Its nearly the same thing as a Catalytic converter. Or Catalyist converter or Cat I can't spell and my chemistry is so rusty I barely remember H2o is water. Anyway its a honycomb looking material that gets hot in the exhaust and reacts with the exhaust gases to react and remove some oxide or other. Something about the Nitrogen in air getting so hot in combustion and reacting and creating Nox's etc. Not sure how different it really is from a gasser CAT similar but probably slightly different. You might find a technical post on it. But CAT is used commonly in a lot of post and is too short so not sure of good search word phrase.

It surely doesn't keep a diesel from belching black smoke or trap soot from escaping by intent. More or less it does restrict the exhaust gasses and is kinda like a trap maybe why its called a soot trap because it seems to soot up and foul over time with a very poorly running engine. Or maybe that it traps the exhaust gas to increase heat for the catalyst reaction?

[6.5 Detroit Diesel]

Get rid of it. You and your truck will be happier. :D

[w6bauer]

Its already off of My rig. I was going to punch the inside out and put it back on but searching online they run almost 400 bucks brand new. I figure there's someone out there who might want it so I decided not to destroy it.
The burb wasn't as loud after I pulled the cat and muffler as I thought. Will a larger pipe give me more sound or just a deeper tone? I do have noticeably better throttle response and I got an extra 2 mpg on My last tank. also I can actually hear the turbo spool now which was never audible with all that restriction.

[More Power]

The "cat" as used in a light-duty diesel is more accurately defined as a Diesel Oxidation Converter (DOC). The DOC is a ceramic honey-combed structure that is washcoated with a layer of catalyst materials (Platinum, Palladium and other rare-earth base metals). These catalysts chemically react with the exhaust gases to convert nitrogen oxides (NOx) into nitrogen dioxide and to oxidize (burn) hydrocarbons and particulate matter (PM = soot).

Jim

[6.5 Detroit Diesel]

Going to 4" is as big as you will need. Anything bigger is kinda pointless. Big tips are fine, but if you start going with to big of pipe the whole way, the 6.5 will sound a little tinny, IMO.
Throttle response, better mileage, and the sound of your turbo, all are a good payback for opening it up.

[w6bauer]

yeah i will definitely be going with a 4 inch system. I need to get a new downpipe though, i see what all the talk is about how it is basically almost crushed in half from the factory.
Good to know about the diesel cat and the fact that it does contain basically the same elements as a gasser which means i will be able to get a good price for it at a scrap yard, and even better if someone is looking to buy one.

Will

[rameye]

Hey be careful the way it looks when your done, the emissions guys look for it!

How to cloak it is th ecause for another post!

[w6bauer]

I haven't consulted the law book but eveyone ice asked in indianapolis tells me there are no regulations for diesel powered vehicles as far as emissions. Almost every diesel pickup at My school has straight pipes and monster stacks in the bed.

Also, apparently there is no set maximum decibel level for any vehicles. They can write you a ticket for disturbing the peace for an extremely loud exhaust.

[rameye]

Good for you!

Here in the great communist state of Ct. if a cat/soot trap was original equipment, you'd better have one for inspection!

Enjoy your much enhanced performance..

[Robyn]

The F codes trucks after 93 came with a "CAT" or whatever you choose to call the things.

They do use rare earth metals to react with the exhaust and to limit the Nitrogen Oxides.

Issue is that iver time and use these units lose their ability to do the job and then they plug up with carbon.
As the units plug up the back pressure goes up and the power goes down.
Also the efficiency of the turbo falls off as the exhaust stream slows.

EGT's go up too as the engine works harder to push the spent gases out and the incoming air flow lessens.


Vicious circle it is.

The "Cats" do eliminate some of the crap but the cost is not effective to replace these things.

If you have to pass inspections then you need one there.


Robyn

[6.5 Detroit Diesel]

Good for you!

Here in the great communist state of Ct. if a cat/soot trap was original equipment, you'd better have one for inspection!

Enjoy your much enhanced performance..

i read that in CA they are going to be requiring a DPF setup. Is that true? If so, I think a rebellion is in line..... :D

[DmaxMaverick]

i read that in CA they are going to be requiring a DPF setup. Is that true? If so, I think a rebellion is in line..... :D

No. When/if (I'm being optimistic) the new Diesel emissions testing begins, only originally equipped emissions components will be required. There will be no required retro-fitting. Meaning, if a truck came with DPF, it will be required. Not required if it never had one.

[6.5 Detroit Diesel]

glad to hear for you guys! ;)

[w6bauer]

If any requirements do come into effect like that I will try to stay under the radar as long as possible. I'm really diggin the increased fuel economy and power. I feel like my rig is actually making less harmful emissions because I'm going through far less fuel per mile. Seems to me that that means I'm burning fuel more completely in the combustion chamber and not dumping excess to burn in the cat. I'm no scientist but I know I'll never put another cat or muffler on my rig. It's nowhere near as loud as my gasser suburb was with with strait pipes. I like the deep grumble better than the crackle of a gasser at high rpm. I talked my roommate into replacin the turbo on his dodge and letting me get his hx 35. Can't wait for even better fuel economy


Will

[SaGutz2005]

The loons in CA will get either Pitchforks and Torches or Spears and Machetties....... and Arnie is going to have His cashews removed with a dull pen knife!............they are so screwed up here in Ca that that they will require something that isn't invented yet......and then wonder why people are all pissed off!