"faking" the cat. . .

ROGUE GTS

Member
Apr 30, 2008
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It seems the 5-0 are cracking down on moddified diesel trucks these days. I'm curious if anyone has given any thought into welding a cat-housing around a 4" front pipe?

Do they just look to see if SOMETHING is there? Would they know the difference between a 4" front pipe with a fake can welded on it, vs the crazy stock piece?

I have a corsa 4" setup and while it's not overly loud even w/o the cat, I hear we might be getting hassled soon. :mad:



On another note, as an engineer it really makes me wonder about the overall effect. No cat, open pipe, and very good milage, vs new truck with cat, dpf, stupid regen, and crap mileage. At what point does burning ~30% more fuel to "clean the filters" cause more pollution. :confused:
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
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Mid Michigan
It seems the 5-0 are cracking down on moddified diesel trucks these days. I'm curious if anyone has given any thought into welding a cat-housing around a 4" front pipe?

Do they just look to see if SOMETHING is there? Would they know the difference between a 4" front pipe with a fake can welded on it, vs the crazy stock piece?

I have a corsa 4" setup and while it's not overly loud even w/o the cat, I hear we might be getting hassled soon. :mad:



On another note, as an engineer it really makes me wonder about the overall effect. No cat, open pipe, and very good milage, vs new truck with cat, dpf, stupid regen, and crap mileage. At what point does burning ~30% more fuel to "clean the filters" cause more pollution. :confused:

1) Where do you live? Hopefully not Michigan.

2) Burning more fuel to "keep the emissions clean" had to be an idea straight from the oil companies.
 
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MAXLLY

No Lemming Here
Aug 15, 2007
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San Diego
Last i heard (from smog station Owner) complete Diesel smog testing is going to start in California in 2012... given the amount of time it takes us to approve a state budget... I would expect inspections and smogging in 2020.:joker:

Other people may know better/more but the only difference i saw between the pipe and the cat was a gold discoloration and a GM part sticker, color prolly due to heat. A person could gut the pipe and run pipe straight through, guess you would have to fakey weld the cat in place. A guy could pass the visual easy enough...

But the CHP/Smog Cop testing at the freeway on ramps... hmmmmm?

I think LB7/LLYs will fare well in the smog inspections.
 
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Kat

Wicked Witch of the West
Aug 2, 2006
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Norco, CA
But the CHP/Smog Cop testing at the freeway on ramps... hmmmmm?

I think LB7/LLYs will fare well in the smog inspections.

We have driven by those several times with Blue and Wendy without issue.

But, I know a couple of members who have received letters saying they better get there smog equipment checked :eek::rofl:
 

motohed

dirty payback
Apr 15, 2008
486
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escondido, ca
But the CHP/Smog Cop testing at the freeway on ramps... hmmmmm?

are they doing that? can they pull you over and actually hook up equiptment and smog your truck?:eek:
 

mytmousemalibu

Cut your ride, sissy!
Apr 12, 2008
2,230
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Kansas
Thank god im in "dont give a rats ass" Kansas (for now) and I have a Fed emission LB7 that never had a kitty or EGR any of that crap;)

Just curious, could a guy tune his truck clean enough to pass without a kitty?
 

Alligator

New member
Nov 9, 2006
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Thank god im in "dont give a rats ass" Kansas (for now) and I have a Fed emission LB7 that never had a kitty or EGR any of that crap;)

Just curious, could a guy tune his truck clean enough to pass without a kitty?

I passed NV state smog w/o a kitty on my Cal. Emissions LB7 running a stock tune with a Edge hooked up 3 years ago. My truck could emit .30 ppm/soot and mine did .05 ppm on a load cell dyno at 25 mph.
 

MMLMM

Tunergeek
Mar 2, 2008
4,086
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www.dyncal.com
Ya know, if they synchronized stop lights, we would spend less time idling our vehicles and reduce emissions, and we'd get to where we want quicker and be less stressed.....
 

Cougar281

Well-known member
Sep 11, 2006
1,809
253
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St Louis, MO
I passed NV state smog w/o a kitty on my Cal. Emissions LB7 running a stock tune with a Edge hooked up 3 years ago. My truck could emit .30 ppm/soot and mine did .05 ppm on a load cell dyno at 25 mph.

That says a LOT about what the :censored: cat does on a diesel (besides plug up)... :rolleyes:

So your truck emits one part soot for every twenty million parts everything else.... What exactly is the DPF for again besides waste fuel (on 2007.5+, obviously)?
 
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LarryJewell

Back with his honey :)
Jan 21, 2007
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Ya know, if they synchronized stop lights, we would spend less time idling our vehicles and reduce emissions, and we'd get to where we want quicker and be less stressed.....

what fun would that be, you'd rarely get to line up next to a cummins then :rofl:
 

Leadfoot

Needs Bigger Tires!
Dec 27, 2006
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On another note, as an engineer it really makes me wonder about the overall effect. No cat, open pipe, and very good milage, vs new truck with cat, dpf, stupid regen, and crap mileage. At what point does burning ~30% more fuel to "clean the filters" cause more pollution. :confused:

I agree. Most emission laws help line somebody's pockets and actually hurt the environment.

Case in point: My buddy has a 1985 GMC 1 ton dually. For emissions testing, the limit is in Massachusetts (and most states) is X parts per million of each "pollutant". Instead of actually decreasing the amount of each pollutant, they decided to put on two belt driven air pumps to pump in air into the exhaust. It doesn't make the engine run cleaner, it just pumps more air into the pipes to "increase the denominator" in the PPM. The tree huggers are happy because it meets the parts per million requirements, but due to having to drive those two belt driven pumps, the truck actually pollutes more than if they had no emissions equipment on it.

Emissions laws are a joke IMO.
 

Diesel Pilot

Hat? Suitcase? 50 BMG?
Aug 9, 2006
1,424
0
36
47
Pickerington, OH
In Ohio, the man just wants to see something under the truck. Could be a cat, muffler, or resonator.

They have been known to give warnings for no "emissions" device, ie muffler or cat. I don't know of anyone actually getting a ticket yet but I'm sure there have been.

Basically, no straight pipe and you are fine. Or don't get pulled over.;)
 

othrgrl

Diesel Addiction Owner
Mar 10, 2008
2,151
4
38
Wilmington NC
www.mydieseladdiction.com
In the counties I've been inspected in here in NC they don't check for any emissions equipment during inspection. We took the fiance's 05 TDI Jetta and as soon as he saw it was a diesel all he checked was lights, horn, wipers, ect. Never hooked to the OBDII for codes or checked under for a cat. We've taken straight piped trucks in too with no problems. With 04.5 you should be fine without a cat (except maybe in CA) because you SHOULD fall under what they had in 04 (LB7) and same goes for 07.5 LMM. Mine is registered in Ohio and my county there doesn't have any kind of inspection.
 

68skylark455

Larry the "Stroker"
Aug 7, 2008
1,091
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Texas
www.larrysperformancepalace.com
I agree. Most emission laws help line somebody's pockets and actually hurt the environment.

Case in point: My buddy has a 1985 GMC 1 ton dually. For emissions testing, the limit is in Massachusetts (and most states) is X parts per million of each "pollutant". Instead of actually decreasing the amount of each pollutant, they decided to put on two belt driven air pumps to pump in air into the exhaust. It doesn't make the engine run cleaner, it just pumps more air into the pipes to "increase the denominator" in the PPM. The tree huggers are happy because it meets the parts per million requirements, but due to having to drive those two belt driven pumps, the truck actually pollutes more than if they had no emissions equipment on it.

Emissions laws are a joke IMO.

I am/was certified for emissions in AZ when I lived there, the techincal reason they gave us was the "smog pump" adds oxygen to the cat to increase the reburning temperature capabilities of said convertor. I had a customer from cali with a 67 impala with a 327-2 smog pumps for a 2 bbl carbed engine-stupid. I had a 1974 chevy luv-350 with a tunnel ram and two 4bbl carbs, big cam-I mixed 5 gallons of premium with 5 gallons of av gas (106 oct) and 1 gallon of alcohol. It blew 0.23 hc's and 1.25 co's-not pump, no convertor no smog at all. I have lots of stories on "smog people" who are in the position to vote in new laws and they are a joke also.:mad:
 

Noreaster

Active member
Jun 13, 2007
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Cape Cod,MA
I agree. Most emission laws help line somebody's pockets and actually hurt the environment.

Case in point: My buddy has a 1985 GMC 1 ton dually. For emissions testing, the limit is in Massachusetts (and most states) is X parts per million of each "pollutant". Instead of actually decreasing the amount of each pollutant, they decided to put on two belt driven air pumps to pump in air into the exhaust. It doesn't make the engine run cleaner, it just pumps more air into the pipes to "increase the denominator" in the PPM. The tree huggers are happy because it meets the parts per million requirements, but due to having to drive those two belt driven pumps, the truck actually pollutes more than if they had no emissions equipment on it.

Emissions laws are a joke IMO.

I don't know if the new emission law has gone into effect yet in Mass, anything 95 & older will be emission exempt