WHat happens if i remove the cat?

[focusedrage]

Im talking about CEL? cause in maryland all they do is check the fuel port and hook up a cable to the ecu... if i remove the cat will it alway show me a cel? or can i some how get around it? will the computer know what i have done?

I ask becasuee im thinking of an o2 eliminator down pipe and some cat elimination too... its alot cheeper then having to set it up with a high flow cat that can be swaped out after its tested. Thanks for any imput.

 

[dnsyang]

It'll be fine....just as long as they don't look under your car....I think it's a $10K fine for not having the cat-converter....

 

[focusedrage]

10000 fine wholll shaz ma taz... that is insane
now who would look? cops? them? what woudl make them suspsioous...? meaby i oculd just put some heat shilds so it looks like i have one? caue thats toooo mcuh money

people hear in md are preety lazy when it comes to auto violations... i mean the cop that puled me over for doing 90 disnt even ##### aobut not having a front licens plate... hahaha

 

[focusedrage]

oh yeah and then why is there an o2 sensor after the cat? i mean it must be used to measure something? woulnt it figure out that i dotn have a cat?

 

[ECLIPSE4x4]

It is used to measure how much pollutants you are expelling. And even if you trick it and reset it, the ECU still will know you are about to have a possible code. It is hard to explain. Basically a dormant code.

Your best bet would to just run a test pipe and when you need to get your emissions done, put the cat back in for the test. Thats what I have to do for PA. I run all year long with out a cat, when I go to get my inspection I put it in. Take about 15 minutes once a year to do.

 

[Airpoppoff]

Originally posted by dnsyang
It'll be fine....just as long as they don't look under your car....I think it's a $10K fine for not having the cat-converter....

10g's???? i dont know about that dude

 

[SOURCE1064]

There is some o2 bypass thing that my shop is getting for me so the sensor doesn't send my ecu a code. It costs $140. When I find out the name I'll let everyone know.

 

[dnsyang]

Originally posted by Airpoppoff


10g's???? i dont know about that dude

Oh yea...I'm talking about the shops, but, if you do it by yourself, it's a fine of $2500 or more, less if your lucky...Here is some info about it:

http://www.state.in.us/idem/ctap/vehicle/manual/ch4converters.pdf

 

[focusedrage]

i think mr. 4x4 has the safest plan its just alittle more fabrication and i can just use my old cat with some 3" flanges.

 

[psi-plz]

i removed my cat when i built my exhaust system and the CEL came on with in 20 miles. but after about 300 or so, it went off never to be seen again. no noticable differences in gas milage, or driving, just more power and quicker spool. i also have a friend that works at the garage i used to work in, so my inspection worries are gone!! i do have a test though, so i could in theory put the cat back in.

 

[spyder99]

Lucky for me I don't have Emission test in Jacksonville. We did about 2 years ago, but not anymore.

 

[GVR4#1353]

what you need to pass if they just check the ECU and look at the fuel hookups (even if they look under the car) is a gutted cat and an O2 sim (should be around $70-$100 for the O2 sim)

the O2 sim plugs into the wiring harness where the O2 would plug in, then tape it up to look like its connected and gut your cat....take a metal pipe or sumthin and punch it out, that way it'll look like you have a cat but you wont have the restriction......just make sure you run the car a bit after gutting it before you go down there cuz the cats tend to spit out metal pieces when they've just been gutted

that will work, take it from a California guy haha

you dont even know what strict is when you talk smog laws until you come here

 

[jdmawd]

Originally posted by focusedrage
Im talking about CEL? cause in maryland all they do is check the fuel port and hook up a cable to the ecu....

when my car was emission tested, all they did was stick something in the gas tank. have me hold the car at 2K for about 15 seconds and that was it.

 

[mrfloppy]

Originally posted by psi-plz
i removed my cat when i built my exhaust system and the CEL came on with in 20 miles. but after about 300 or so, it went off never to be seen again. no noticable differences in gas milage, or driving, just more power and quicker spool. i also have a friend that works at the garage i used to work in, so my inspection worries are gone!! i do have a test though, so i could in theory put the cat back in.

no noticable difference in gas mileage? you kiding... come on you have to loose gas mileage. i don't know one guy with a gutted cat or test pipe that just gets no notice out of the all the more stopped fill ups needed.

 

[GSX24PSI]

what you can do is get an 'off-road' pipe then you take the heat sheild off from your cat and then weld it on to the test pipe then bolt it on to your exhaust...so it looks like you have a cat bolted on to your exhaust

 

[doug]

Originally posted by mrfloppy
no noticable difference in gas mileage? you kiding... come on you have to loose gas mileage.

I didn't notice any difference in gas mileage either when I put my catless turbo-back on. And I don't see how not having a cat would cause your gas mileage to go down anyway-- if someone knows, please explain.

And about the CEL-- I had my exhaust about 8 months before I got my first CEL. Now I get one every few weeks or so. Just pull the negative terminal off the battery to reset the ECU and the light will go away. At least for a while.

Casper's Electronics has an O2 sim thing-- I don't have the link handy, but a web search for their site should be easy enough.

 

[GVR4#1353]

Originally posted by doug

I didn't notice any difference in gas mileage either when I put my catless turbo-back on. And I don't see how not having a cat would cause your gas mileage to go down anyway-- if someone knows, please explain.

it wouldnt, without a cat and no O2 sim the O2 after the cat would tell the ECU you're running rich and lean the engine out

 

[psi-plz]

yes, GVR4 you are right on that one. no cat actually leans it out. but in my case w/ no other mods. not enough to knock. and really, i had not real milage difference. maybe a gallon or two b/c of the larger exhaust.

 

[focusedrage]

on gas milage... silly, the mixture is burned and gone by the time it reaches the cat all a cat does is use a platinum catalyst thing to facilitate the continual burnig of gas as it goes down the pipe, less of that means less hydrocarbons that is why cats are fricken hot and some air injected into them. your gas milage shouldent change

 

[psi-plz]

2g's have a post cat o2 sensor measuring rich/lean condition of the exhaust. ecu then adjusts accordingly. so yes, it could change your gas mileage.

 

[focusedrage]

hmm i thougth that was what the one in after the turbo does?

 

[GVR4#1353]

Originally posted by focusedrage
on gas milage... silly, the mixture is burned and gone by the time it reaches the cat all a cat does is use a platinum catalyst thing to facilitate the continual burnig of gas as it goes down the pipe, less of that means less hydrocarbons that is why cats are fricken hot and some air injected into them. your gas milage shouldent change

without a cat the unburnt fuel travels through the exhuast and tells the "after cat" O2 sensor you're running rich and the ECU leans you out a bit....it wont change your gas mileage that much UNTIL the unburnt fuel fouls out your O2 sensor and you dont get accurate readings from them anymore then your ECU wont compensate as well and you start losing fuel efficiency....how long it takes to foul the O2 depends on how rich you were running to begin with though....its best to just run the 02 sims and be done with it all