Can I kill the CAT

[MVaden]

Will it void the factory warranty if I cut out the cat? I've read that some are doing this to the new 04. 5s to increase milage and power.

 

[fencebuilders]

yup.

 

[tURBOdIEZEl]

as far as i know, you will

 

[rbattelle]

It's also illegal, and you can get fined.

 

[TCDiesel]

In Minnesota,If vehicle is use for any type of commercial operations,OR LICENSE OVER 9000 GVW,LICENSE TRAILER OVER 10,000 GVW,and you get stop by Commercial Enforcement or a spot check. They will use their mirrors to check for any alterations to exhaust system. Not only does it have to meet Emission standards it has to meet noise standards also. THEY HAVE A NO EXEMPTION POLICY. You will be put out of service, until corrections are made.

 

[rashwor]

Another option...

is to take the cat off, slice it open and cut the guts out, and seal it back up. Be sure to cut it on the top or that when you put it back together the new "seam" is up and not down. I think I will do this when I get a new truck.

 

[GCross]

Federal emissions rules state that "It is unlawful to alter the exaust system of a motor vehicle in any way" You will void your waranty and be at risk of having to retore it to OEM standards if you remove the CAT. Rashwor's idea may work as long as you don't live in a state that requires smog checks as here in Cal.

 

[Udaloy]

All things considered, will killing the cat (always a fun pastime) give better mileage?

 

[jelag]

The cat is nothing more than an exhaust restriction... ... I haven't taken one apart on our trucks but have had several apart on gas fuel vehicles... . there were 2 designs... one a honey comb that we saw broken out... . its hard and will crumble with something rammed into it... ... pry bar, pipe etc and the remains will fall out of the pipe... . the other design was pellets which are tightly packed together..... you simply remove the screen that retains the pellets and they fall out.....



The performance increase comes from the lack of restriction... . in some cases its very noticeable. . others it isn't... . I'd guess that you'd at least seem EGT readings lower with it gone... . and some better MPG readings as well... .



BTW - in my state emmission tests on diesels is nothing more than a check for visible smoke... . in some states however its with a gas analyizer and that will trip either a bad or missing cat in 15 seconds... . which you'd have to replace to retab your truck.....



Jim

 

[Txredneck]

MVaden ive drove thru dallas and stayed in dallas before and have had no problems with running a straight. ive only been told once to put a muffler on my truck and that was by D. O. T if they ask say it fell off couldnt afford a new one

 

[MVaden]

Thanks for all the replies to my question, this site is really great.



I'm going to get the reflash done and see if that helps the mpg's, if it does not help I may pull the cat and gut it, then reinstall it.



As far as inspection stickers go I was told I would be OK here in Texas. I talked to a Technician and he said it would pass with no cat on it.

 

[ttreibel]

Originally posted by Txredneck

say it fell off couldnt afford a new one

I bet that works great when you're in a brand new 04. 5 Laramine LOL

 

[Peter Campbell]

I think the other half of the problem is the after shot of fuel. If you could get rid of that and the CAT you would see some efficiency. The after shot keeps the CAT warm, and oh by the way makes some power as it makes waste heat on purpose.