cat delete question

[JimmyDiesel]

If you were to remove your cat, are there any long term negative effects? A friend mine told me that some engines are designed to run with that back pressure, something to do with intake-exhaust valve overlap. Did all 24v engines come with a cat? Seems like a no-brainer to remove it, but I don't want to cook my valves.

The truck in question is an 05

 

[SierraRam]

No problems on a turbo diesel except possablly with the law.

 

[Wingate]

Theres one other problem that may rear its ugly head from removing the cat... . I removed mine (actually the entire exhaust system) and lost approx. 5 MPG!!!. . It wasn't due to an engine issue, it was due to the new exhaust sounding so good, I was driving with my foot crushed into the carpet just to hear that sweet sound!!... Mileage has came back pretty good now that Ive had the exhaust for awhile.

 

[dan.poitras]

If your area requires "drive clean" (ontario) or emission testing your truck will fail the test. Not because of excessive opacity but the pre test inspection shows the the suspect vehicle should have a catalytic converter

 

[macdaddy]

If your area requires "drive clean" (ontario) or emission testing your truck will fail the test. Not because of excessive opacity but the pre test inspection shows the the suspect vehicle should have a catalytic converter

This is true!!!!!!.



Jimmy D... .



Simply do what I did. I removed the insides of mine using a large hammer and pick. and installed on my silverline 4" Turbo back system.



If I were you I would cut it off, remove it's contents and simply weld it back in. I noticed significant spoolup improvements with it removed. I also picked up around a full 1 MPG average city/highway (hand calc).



Mac

 

[JimmyDiesel]

oh yeah

Thanks guys, I think I am going to do just what macdaddy said and just hollow it out. Its cheaper that buying the delete kit!Oo.

 

[Deleted member 995608]

I took off my cat on my 04. 5 right after I bought it new and ran a straight pipe for the first 100+k miles. I recently put it back on for noise reduction (it helped a lot) and also-Ca will smog in 2010. I HAVE not seen any reduction in milage or power whatsoever.

 

[Steev]

Even though there's a smog inspection coming in CA in 2010 - it's still not 100% finalized on the details.

There's a visual inspection (so gutting the kitty is a good idea in this case), a computer (so far not newer CAN based trucks yet), and a snap test to see how much smoke is coming out the pipe. So far nothing's going in the pipe yet so you should be good for at least a little while.

Would be a good idea to start a Smog savings account in case they start stickin things in the tail pipe... . don't trash any of your OEM stuff as you start modding.

 

[JHenry]

Theres one other problem that may rear its ugly head from removing the cat... . I removed mine (actually the entire exhaust system) and lost approx. 5 MPG!!!. . It wasn't due to an engine issue, it was due to the new exhaust sounding so good, I was driving with my foot crushed into the carpet just to hear that sweet sound!!... Mileage has came back pretty good now that Ive had the exhaust for awhile.

Ha Ha. Oo. So that is what happened to my mileage!! Seriously, if you take it easy, it will improve your mileage, but that can be hard to do.

 

[macdaddy]

Even though there's a smog inspection coming in CA in 2010 - it's still not 100% finalized on the details.



There's a visual inspection (so gutting the kitty is a good idea in this case), a computer (so far not newer CAN based trucks yet), and a snap test to see how much smoke is coming out the pipe. So far nothing's going in the pipe yet so you should be good for at least a little while.



Would be a good idea to start a Smog savings account in case they start stickin things in the tail pipe... . don't trash any of your OEM stuff as you start modding.

This is correct... ... .



My friend and fellow TDR member was stoped in a "Data Gathering" check point where they ran a snap test Particulates ppm.



If this is all their looking for, which I believe it is, the CO and NoX may not be an issue with respect to requiring a catalytic converter. Hopefully.



Mac

 

[Wingate]

Ha Ha. Oo. So that is what happened to my mileage!! Seriously, if you take it easy, it will improve your mileage, but that can be hard to do.

Yep!!. . Now that I've had it on my truck for awhile, I've slowly gotten back to driving it normal. I DID check my fuel mileage last week on several 50-60 mi. runs down the local interstate. The mileage is definitely up 1-1. 5 mpg.

 

[BHanna]

I've heard of some places shooting the cat with an IR laser thermometer to see if it's been hollowed out. Anybody seen this? I'd sure like to just replace my exhaust with a turbo-back when it rots out.

 

[HBarlow]

If you were to remove your cat, are there any long term negative effects? A friend mine told me that some engines are designed to run with that back pressure, something to do with intake-exhaust valve overlap. Did all 24v engines come with a cat? Seems like a no-brainer to remove it, but I don't want to cook my valves.

The truck in question is an 05

If your goal is to allow the throaty sound of a real diesel be heard a better choice might be to remove the factory muffler and relace it with a straight section of pipe leaving the cat convertor in place. I did that on my '06 and it sounded great. It wasn't noisy and didn't resonate in the cab, was fairly normal under steady throttle but it sounded great with my foot in it.

 

[Deleted member 995608]

if your goal is to allow the throaty sound of a real diesel be heard a better choice might be to remove the factory muffler and relace it with a straight section of pipe leaving the cat convertor in place. I did that on my '06 and it sounded great. It wasn't noisy and didn't resonate in the cab, was fairly normal under steady throttle but it sounded great with my foot in it.

100%. . . . . . .

 

[cerberusiam]

It wasn't noisy and didn't resonate in the cab, was fairly normal under steady throttle but it sounded great with my foot in it.

Harvey, do you have significant hearing loss? :-laf



EVERY single truck I have ridden in that had a straight pipe, with or without a CAT, drove me crazy with drone. Some were tolerable with no load but still noticeable. ALL of them with a trailer were enough to get me grinding my teeth after a short time.



They do sound good but drone is baaaaaddd, and I have hearing loss.

 

[HBarlow]

Harvey, do you have significant hearing loss?... ... ... ... :-laf

Yes. It may have been rattling the cab but I thought it sounded good!

Actually my wife rode in it occasionally and friends rode in it a few times. I don't think it did drone.

Have you ridden in an '06 w/muffler delete? Maybe the cat converter and, I think it also had a small resonator that I left on. I only removed the large muffler.

 

[cerberusiam]

Yes. It may have been rattling the cab but I thought it sounded good!



Actually my wife rode in it occasionally and friends rode in it a few times. I don't think it did drone.



Have you ridden in an '06 w/muffler delete? Maybe the cat converter and, I think it also had a small resonator that I left on. I only removed the large muffler.

Yep, 06 with 5 inch exhaust and no muffler, and 4" with no muffler. I would have shot the truck to put me out my misery after 100 miles. #@$%!

 

[JimmyDiesel]

If your goal is to allow the throaty sound of a real diesel be heard a better choice might be to remove the factory muffler and relace it with a straight section of pipe leaving the cat convertor in place. I did that on my '06 and it sounded great. It wasn't noisy and didn't resonate in the cab, was fairly normal under steady throttle but it sounded great with my foot in it.

Harvey,



I actually did that on my 92 and it was unbearable. The reason I wanted to remove the cat is I suspect it is getting clogged. I have been slowly noticing slower spooling of the turbo, not just from a stop, but when you are moving and really get on it also. alot more smoke that usual too. I have got to get the gauges installed in this truck, gonna transplant them from my 92.

 

[HBarlow]

Well, I guess being nearly deaf has its advantages. All this time I thought my truck sounded good and didn't drone inside.

 

[WWomack]

So if I remove the Cat will it be a problem while towing? Such as back pressure or loss of engine braking because of lack of back pressure since removal of the Cat?? I sure don’t want to find out when I’m coming off the mountain with a 12k load.



I thought as long as I left the stock muffler in place the truck would not make too much more exhaust noise. Has anyone encountered any problems with the computer throwing codes because of removal of the Cat? I can’t find an oxygen sensor so I don’t think it will be a problem. Any advice is appreciated.