cat delete

will1551 · Post by **will1551** » Tue Jul 29, 2008 5:44 pm

ok the only thing im not sure about with this mod is how to get around my o2 sensor? Do i have to drop $400 on a programmer or is there a cheaper way to do it? Btw the reason im doing this mod is because im hoping to decrease back pressure some since i went with 2.25" pipes instead of 2.5" (idiot!), and i guess the added decibel level would be nice too lol

Post by **HenryJ** » Tue Jul 29, 2008 8:05 pm

It is illegal to delete the cat, as I am sure you know. You will probably have to find someone who can reprogram your PCM to disable the rear sensor.
The hand held programmers can not do this as it to is illegal.
There used to be some sensor simulators out there. I think Casper electronics was the company. I heard that they got in hot water as it is illegal to sell a product that disables emissions systems.

The cat we have is of a high flow design. You are not going to find performance gains in its removal. If loud is what you want , deleting the muffler may be more desirable. Small pipe is going to be high pitched. I have a feeling none of these band-aids are going to be a satisfactory substitute for installing a system that may offer a better tone.

will1551 · Post by **will1551** » Wed Jul 30, 2008 9:42 am

Oh ok i just figured i could use the programmer to ignore the reading from the o2 sensor, my friend who had an f-150 w/ the 5.4 used his programmer to do somthing like that. But anyways im not sure i can go with any bigger pipes than 2.25" just simply because im not sure i could get around my spare.

Post by **HenryJ** » Wed Jul 30, 2008 11:25 am

you say 2.25" pipes. Does that mean duals? If so that is plenty big.

will1551 · Post by **will1551** » Wed Jul 30, 2008 3:55 pm

yes sir i have a cat back with a single glasspack going into a y-pipe and then branching out on both sides of the spare. soo with that said do you still stand by your assumption that deleting the cat wouldnt net much performance gain (to be perfectly honest i kinda just want to do it for the sound, im just looking for an excuse to justify going through with it)?

Post by **HenryJ** » Wed Jul 30, 2008 6:06 pm

Still say you will see little gains from a cat delete.

If you are just looking for loud replace your muffler with a Y pipe.

The cat is not designed to reduce sound. It does somewhat though. The muffler is designed to control sound. The louvers on the interior of your glass pack open the flow to absorb sound. The twin pipes also tend to separate the sound and reduce it too.

I don't know how old your system is , but the system needs time to season. It may take as long as a year for it to settle out.
Glass packs do tend to get noisy with time. Wait it out and you may get the blown out glasspack sound you seek. One thing to think about is that it is much noisier for everyone else that has to listen to your truck, than it is for you. Pipes run all the way to the back are going to quiet it substantially.

You will never have this sound like a V-8. I would say find something else to mess with.

You not find me saying you absolutely can not remove the cat. It can be done, but as I have said before...no benefits will be gained.

I know there is no information on how the fool the rear sensor on this forum. You will just have to search the internet for a way, or find someone who will program your PCM.

will1551 · Post by **will1551** » Thu Jul 31, 2008 6:23 am

Yeah ive had my system for a little over a year now and its definatly gotten noticably louder. And im aware the truck wont ever sound like a v8 (just relativly close), but i just like the sound of trucks ive heard that are running no cat and some sort of high performance muffler (yes im aware a glasspack isnt really a high performance muffler lol). Btw while we are on the subject i think ill probably start by removing the pre cat and replacing it with a peice of straight pipe, and correct me if im wrong but i think that it wont affect the rear 02 sensor?

Post by **HenryJ** » Thu Jul 31, 2008 7:52 am

will1551 wrote:i think ill probably start by removing the pre cat ... it wont affect the rear 02 sensor?

Correct.

HCO4x4 · Post by **HCO4x4** » Sat Aug 02, 2008 6:40 pm

Has anyone seen or tried one of these?

O2 Sensor Simulator on Ebay

Rockrz · Post by **Rockrz** » Sun Aug 03, 2008 5:24 am

will1551 wrote:deleting the cat wouldnt net much performance gain

It may help you keep money in your wallet since cats are being stolen these days by people who sell them for scrap.

These things contain precious metals that are high dollar, so crack heads all over the US are stealing these to cash in so they can buy mo crack rock!

When I get my exhaust work done, I'm going to have them make me a "test pipe" that bolts right in. You know, just in case I want to go to the track and make a few quarter mile passes

There's a gizmo you can buy that you simply plug into, instead of the rear O2 sensor, that simulates an "everything OK back here" signal to your computer so you don't throw any codes.

Of course, it's for "off road use only"

will1551 · Post by **will1551** » Sun Aug 03, 2008 9:02 am

Yeah i was actually thinkin bout selling mine after i read about that... but not to buy crack lol.

roadrunner · Post by **roadrunner** » Sun Aug 03, 2008 11:04 am

NAPA used to sell those "test pipes". I think they quit due to liability issues. Seems a lot of folks were neglecting to remove them when they were done "testing" and failing to put the cat back on.

Rockrz · Post by **Rockrz** » Sun Aug 03, 2008 2:49 pm

roadrunner wrote:Seems a lot of folks were neglecting to remove them when they were done "testing" and failing to put the cat back on.

I can't imagine anybody doing that

I saw a thread about removing cats on another board and they guy claimed he is able to pass annual emissions testing with no problems.

If that's true, then removing the cat may violate the letter of the law but it wouldn't violate the spirit of the law if your vehicle still passes emission testing since you wouldn't be effecting the emissions output to make it pollute more.

That would be an interesting argument in court, but I don't think I'd want to spend the money to see if it would work. Not with all the love mutha earth hippies they'd have on the jury

Post by **HenryJ** » Sun Aug 03, 2008 3:50 pm

Rockrz wrote:I saw a thread about removing cats on another board and they guy claimed he is able to pass annual emissions testing with no problems.

Claimed may be the key word. There may be more to that story. His test may not have required a sniffer or visual inspection. A simulator to fool the OBDII and a light check as the only test could pass. It would be emitting emissions beyond the limits though.
The argument can be made at every step, but still why do it for no gains? At worst our crew cab trucks are still covered for another year. If you have a problem the emissions system is still covered.

Rockrz · Post by **Rockrz** » Sun Aug 03, 2008 5:00 pm

Well, the guy claimed that the tech doing the state inspection simply stuck the probe up his tail pipe and went back to his testing machine controls to get the reading and never looked under the truck.

He said he was in a rural area were they often don't do much of a visual inspection when you go down to get your state inspection done.

Heck, I've heard that a hi-flow cat can cause codes and it's best to stay with the stock cat since the newer ones flow alot better than 5 or 10 years ago.

Yeah, I figured I'd better leave stuff like this as is but it never hurts to discuss

Post by **HenryJ** » Sun Aug 03, 2008 5:23 pm

There were some pretty good gains to be seen in the older cats. The old pellet style could be a mess some times. Big and heavy too. They have come a long way since then.

Oh, and that metal that is being recycled from the cats is platinum. Some of the big ones have as much as $30 worth. Or at least that is the value a used cat may have.

Rockrz · Post by **Rockrz** » Sun Aug 03, 2008 5:31 pm

Yep, there may be some value in running a test pipe just so there's no cat to steal...if you live in a county that doesn't require emissions testing like I do.

They never look at anything when I get my inspection sticker except for the VIN and mileage

Post by **HenryJ** » Sun Aug 03, 2008 5:39 pm

I'd rather steal your battery. It is worth $50 on the used market. Heck why not punch a hole in that plastic gas tank and help myself to $40 worth of fuel while I am at it.
If you removed every part worth a buck you would be left walking barefoot.