Cat and Emissions

[WRB Diesel]

I have a complete 4" SS exhaust with no cat, getting ready to install the pipe I am starting to worry about passing emissions or having a sight check completed. I am wondering if any of you fellow TDP's have had any luck in the state of WA with a no cat system. How much would an installed high flow cat affect the overall performance of a 4" exhaust? Thanks for the help.

Aryn

[BigGun J]

I live in Seattle and have had my 93 7.3 ford tested at Renton three times in the past 6 years. It is stock but, they have never done a visual with any vehical I have owned. They just insert the pipe and try and blow up the truck. I give them two try and then shut it down in the booth and ask for the manager. If you will not move your truck and insist they are trying to blow up your old rid and want to see a manager they will give you a pass waiver. I have only done this with the diesel. If you do two pop test and they did not get a reading, shut it down in the line. The place has always been full and they get jumpy with all the cars waiting in line. When you hit the govonor in the booth almost all the car drivers about S###@ themselfs. I think they only look for smoke and not noise.?. My old ford has a muffler but it is loud a hell under that canopy. Give it a go. All they can do is fail you.

Jim

[DennisG01]

If it was me, I would call or, better yet, visit some inspection stations near you before you do the mod, if you're worried about it. Find out if they'll pass you without the soot trap. There's no harm in asking! This way you'll know for sure, rather than just taking our word for it.:)

[Robyn]

Hmmmm, why all the worries.

These guys at these inspection stations are niot going to scrutinize the cat up close and personal (as in with a microscope)

Before you install your system build a 4" throughput that looks like a cat but is nothing more than a heAVY SHEETMETAL can around a section of pipe.

Expand the ends so your new cat will fit over the pipe and either clamp or weld in place. (Clamp it and then tack weld it some so it does not get loose)

You can copy the shape of the original to a great extent and this will fill the need of the Visual.

Now the "lookers" will be happy and you wont be sweating the test and having a fit worrying about it.

There are a lot of diesels out there that have had the cat gutted.
On a gas rig the mods to the cat can be detected easily with the sniffer unless the little creature is in very good tune.

A sharp nose will however catch the difference on the diesel that does not have a working cat. The exhaust with the cat has a distinct odor with a sweet pungent smell that is not there without the cat.

Bottom line
The cat causes a lot of heat to be retained and overall is bad for your engine and your wallet in the long run.

Now you might look into the high flow 4" cats that the aftermarket offers.

This will not only satisfy the visual but will help reduce the emissions if your worried about such.

Im in Oregon just south of Portland. The diesels under 8600 GVW get inspected and the stuff over 8600 dont even have to show up, just pay your $$ and get your license.

This is why I always buy the HD rigs. NO HASTLE :D

Now you have some options.

Install the 4 inch without a cat and worry
Ask a few questions and maybe get blind sided
Install the 4 inch with a psuedo cat
Install the 4 inch and an after market 4 inch cat. Probably the best "Honest option" The 4 inch is so much overkill on a 6.5 that the slight restriction with the BIG cat is probably no biggy anyway

Depending on your mindset you can take your choice.
I know what I would do.

I am not in favor or altering things to the point that they are not somewhat clean in the way they run but by the same token we must maintain the health and well being of our little mechanical friends. :)

This same mindset applies to the wallet. :D

There you go, my 2 cents worth, ball is in your court.

Best as always

Robyn

[DmaxMaverick]

Simple solution....

Install your system, and fab a flange for your cat, and make a straight pipe with the same flange. Install the cat for your inspection, and switch it out for the straight pipe for your "off highway" use. It'll cost a little more up front, but you'll be legal, and everyone will be happy.

Keep in mind, it is unlawful to tamper with or modify an emissions system, so we should not recommend you operate your truck on the highway without a cat, if it came with one. Currently, there is no regulation for "off highway" or recreational use. They haven't smogged Nascar, yet! Actually, I think I'd rather see that, than restrictor plate races (at least there would be some logic to it).

[rameye]

I was in the same dilemma recently...new exhaust...to cat or not to cat??

I said screw it ..no cat... Then CT came up with a new diesel emissions test!! This to include a close visual (yes, they actually do crawl under that truck and look it over). Ok so I panic....I have the old soot trap...hmmmm Damn the torpedoes full steam ahead!. I cut the trap ...filet it lengthwise,, dump out the innards...open up the inlet and outlet to match new system...and tack it back together and new system...voila!!

Engine is original equipment for the most part...passes with flying colors...no visual snafus yet...

PS: I do troll for some of the dumbest looking techs..and bring my truck there ...the younger the better, I think they might lack some ambition. No offense intended if you are an emissions tech :0

[trbankii]

So, if one were to want to keep the cat, does it make sense to open things up every now and then and clean the soot out of it?

[16gaSxS]

I have another option.............MOVE TO MONTANA become a Dental Floss Tycoon. Here in Montana we have no emissions tests and cats are always getting lost! (here kitty kitty) :rolleyes:

[Robyn]

Speaking of Cats getting lost.

It has become the fav passtime of many a crook now to not only lift your air bag, they now hack out your cat too.

Just leave the truck sit downtown over night and your cat issue will probably be eleviated for you at no charge.
Now keep mind, the stereo and a few other things might also go missing too. :D

I think I would opt for the 4 inch Cat. The 4 inch system will flow so much more than a 6.5 ever thought about breathing that the little tiny difference with that huge Cat is not gonna make squat.

The sniff test as well as the visual will go fine, you can sleep nights knowing that you are doing your part to help something Global and all will live happily ever after. :D


Robyn ;)

[DA BIG ONE]

Speaking of Cats getting lost.

It has become the fav passtime of many a crook now to not only lift your air bag, they now hack out your cat too.

Just leave the truck sit downtown over night and your cat issue will probably be eleviated for you at no charge.
Now keep mind, the stereo and a few other things might also go missing too. :D

I think I would opt for the 4 inch Cat. The 4 inch system will flow so much more than a 6.5 ever thought about breathing that the little tiny difference with that huge Cat is not gonna make squat.

The sniff test as well as the visual will go fine, you can sleep nights knowing that you are doing your part to help something Global and all will live happily ever after. :D


Robyn ;)

Platinum can be found in many cats @ better than $2k an ounce they will really start to go south, now you know!

[Robyn]

Yup
The black market for parts is good but scrapping out cats for that kind of $$$ is sure inviting.

Robyn

[93GMCSierra]

I have another option.............MOVE TO MONTANA become a Dental Floss Tycoon. Here in Montana we have no emissions tests and cats are always getting lost! (here kitty kitty) :rolleyes:
yup North Dakota too, I dont know what a cat is really I have only seen them in piles in the mufflershop floor.

[BigGun J]

Wow what a head line for the news. Crack head breaking into muffler shops in North Dakota to lift cats! They are just stupid enough to do it, the news that is.

Jim

[DaveNY]

Another Battery powerd Saws-All in the wrong hands. Better license and register them tools!!!!!

[mrwilecoyote]

I was in the same dilemma recently...new exhaust...to cat or not to cat??

I said screw it ..no cat... Then CT came up with a new diesel emissions test!! This to include a close visual (yes, they actually do crawl under that truck and look it over). Ok so I panic....I have the old soot trap...hmmmm Damn the torpedoes full steam ahead!. I cut the trap ...filet it lengthwise,, dump out the innards...open up the inlet and outlet to match new system...and tack it back together and new system...voila!!

Engine is original equipment for the most part...passes with flying colors...no visual snafus yet...

PS: I do troll for some of the dumbest looking techs..and bring my truck there ...the younger the better, I think they might lack some ambition. No offense intended if you are an emissions tech :0
CT sucks. Yes they do visual. it is a violation of both federal and state laws to remove or tamper with any emissions device.
That said these so called "cats" are not catylitic convertors as you would think of in a gasser. They are really just soot traps. Since most diesels rarely get hot enough egts at the soot trap the don't work effiecintly anyway and clog. the exhaust systems stock on these trucks are like trying to breathe through a hollow coffee stirrer. Now I didn't remove my cat but if i did I would remove it. Carefully cut a nice square hole along the top side of it. Smash out ALL the guts including insulation. Neatly weld cut piece back in and reinstall cat . It will despite what some say not make any noticable sound difference and easily pass visual inspection. Also as far as passing emissions bear in mind, our trucks were designed to run on low sulphur and in some older cases high sulphur fuel. So when you load up with ULSD your truck will pass emissions with flying colors without that ulgy little kitty.