"taking the cat out"....

[jpaitala]

If you gut your cat in a emission controlled state, will the truck pass emission testing?

I think if it will pass over there in US it will pass here also and I would like to make my baby to breath a bit better by gutting the cat.

What do you think?

[Billman]

Depends on what is included in your emission testing.

Here in NY, in NYMA Area, Opacity testing for GVW over 10k.

I say Gut It. It's a big restriction.

[G. Gearloose]

Even my clapped-out-banks-turned-up K5 blew consistant 0.0 opacity, better than my '96 with a cat at 0.3%

Limit was 20.0%

I'd be more concerned with the cat coughing out its collection into the machine, than its absence.

[Kennedy]

From what I gather, the overwhelming majority of the "no pass" trucks failed the VISUAL inspections after passing the opacity with flying colors.

I always said, your tailpipe could be producing sunshine, mmoonbeams, and pure oxygen, but if the cat isn't at least there in spirit, ;) you'll fail.

[jpaitala]

I think I will gut it, but not sure should I do it now or after a month when I have already had the truck inspected....

[DmaxMaverick]

If you have a "faux cat", the worst the emmission tech is going to do is tell you to replace your failed cat. Then you are back where you started. If it passes, then no one will be the wiser.

I am in no way encouraging anyone to violate your local emmission regulations. If you modify your emmission system, and it passes the emmission test, then you are not really violating anything but some politician's anal tendancies.

[MTTwister]

Seems to me if it's a soot trap, then there's a good chance of it puking it's load during an emissions test. If you gut it, it won't load up, the truck should breathe easier, etc. I gutted mine and re-hung it - Just in case.. Now I could usesome bigger / better plumbing further on back - someday soon..

[jspringator]

Is there any kind of performance soot trap (there are performance cats for Miatas) that would let an exhaust shop install a larger exhaust? What about a soot trap from a Cummins or Powerstroke? If it didn't affect performance, and it worked, I wouldn't mind doing my part for clean air. I don't want to buy something that doesn't help with particulates.

[DmaxMaverick]

Try a CA emmissions early model, or a late model (LLY) exhaust system off a Durmax. There should be plenty around and they are 3 1/2", including the cat. The cat's on the Duramax don't seem to hinder the 6.6's performance, so on a 6.5, it probably wouldn't even be noticed.

[Kennedy]

The Dmax cat isn't a whole lot larger, and by my testing, is quite restrictive at the 300HP level. Swapping exhaust on my LLY was good for asolid 15HP and substantial torque. Gains were from bottom to top...

[jpaitala]

I think I will play it safe and remove the cat after the inspection, since last time the "smoke test" passed with ease.

I'm thinking of building a replacement tube for the cat that I can swap out for the yearly inspection.

[hug]

I installed the Kennedy exhaust with the cat guted and per instructions drilled a series of half inch holes in the pipe passing through the cat to cut back on interior noiseand welded each end. No tailpipe test here but passes the visual with flying colors. smile.gif

[DmaxMaverick]

I hear what you're saying, John.

The Duramax exhaust route is a better option than most will have. It will surely be better than current options for those that want to stay in compliance.

[jpaitala]

Duramax exhaust system would be great I think, but there's no Duramaxes here, so not any DM exhaust systems on sale.