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Thread: Drilling my catalytic converter?

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    LX User vteckiller's Avatar
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    Drilling my catalytic converter?

    I've heard of people " Drilling out " there cats? how do they get a drill bit that big? i was thinking.. screw it.. drill a shit load of 1/4inch holes all over the place on the outside?
    LIFE IS SHORT, DRAG IT OUT!



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    Re: Drilling my catalytic converter?

    Unbolt the cat. Take a long drill bit and drill it out. I however take a long 1/2" drive extension and just beat it through with a hammer. Bolt it back up un bolt the pipe in front of the axle start the car and blow all the crap I knocked loose out, then bolt it back up. Free high flow cat probably would have a hard time passing emmissions if I had to worry about that crap. I actually just removed mine though.

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    lostforawhile's Avatar
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    Re: Drilling my catalytic converter?

    Quote Originally Posted by vtechkiller View Post
    I've heard of people " Drilling out " there cats? how do they get a drill bit that big? i was thinking.. screw it.. drill a shit load of 1/4inch holes all over the place on the outside?
    you are joking right?

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    LX User vteckiller's Avatar
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    Re: Drilling my catalytic converter?

    Quote Originally Posted by lostforawhile View Post
    you are joking right?
    I heard it from a buddys dad, but sound like shit, he said no different than any other riced car.. But my car ain't riced.. I was personally gonna say take a price of rebar and unbolt one side. And hammer that rebar through.
    LIFE IS SHORT, DRAG IT OUT!

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    3Geez Veteran A18A's Avatar
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    Re: Drilling my catalytic converter?

    take out the cat, scrap it, buy a pipe to replace it & a feed with the money you got from the scrappy

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    DX User rocketman's Avatar
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    Re: Drilling my catalytic converter?

    Don't bother. Buy a test pipe. I just bought a CAT test pipe made of stainless for $29.00 for our '95 Civic . . . and the rest of the exhaust for the Civic for another $115 . . . and it's installed and works fine. A little loud when you "get on it". . . but it's the last exhaust I'll ever put on that car. Want the website for the test pipe? It fit perfectly. Rocketman

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    3Geez Veteran MessyHonda's Avatar
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    Re: Drilling my catalytic converter?

    your dad buddy ment to gut the cat not drill holes in it.

    1989 Honda Accord LX-i
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    LX User vteckiller's Avatar
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    Re: Drilling my catalytic converter?

    Quote Originally Posted by MessyHonda View Post
    your dad buddy ment to gut the cat not drill holes in it.
    well he is kind of... so i dunno.. dudes crazy.. i myself would just get a tube same size of the tube that goes to the cat, get it flaired out like so many centimeters.. so itll just fit right on it with a couple wacks of a hammer.. then some C clamps.. cause i don't have a working welder anymore.
    LIFE IS SHORT, DRAG IT OUT!

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    LXi User CzEcHy's Avatar
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    Re: Drilling my catalytic converter?

    Quote Originally Posted by rocketman View Post
    Don't bother. Buy a test pipe. I just bought a CAT test pipe made of stainless for $29.00 for our '95 Civic . . . and the rest of the exhaust for the Civic for another $115 . . . and it's installed and works fine. A little loud when you "get on it". . . but it's the last exhaust I'll ever put on that car. Want the website for the test pipe? It fit perfectly. Rocketman
    Try finding a resonated test pipe for an 86 to 89 accord, I've had 0 luck.

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    LX User vteckiller's Avatar
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    Re: Drilling my catalytic converter?

    Quote Originally Posted by CzEcHy View Post
    Try finding a resonated test pipe for an 86 to 89 accord, I've had 0 luck.
    Why would it have to be for an accord? or 86-89 for that matter? find a year that works with little to no extreme modifications.. unless you're a everything has to be stock/factory person.. the technology from then to now.. id try to find the newest yr test pipe possible. or at least one with good flow.. but im still trying to figure out if im going with a 2inch pipe flared out to like 2.05 or something on the ends.. or just go with a pipe thats 2.05 all the way around no flaring needed.. cause if you look at it.. the catalytic converter isnt bolted on. its two pipes sleeved together then welded. at least mine is that way. anywho long storys short.. i live in oregon where there is no smog law. There totally should be.. post me back with your idea's.. im new to the honda world sorta.. im in the makings of a 89 lxi sleeper.
    LIFE IS SHORT, DRAG IT OUT!

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    Re: Drilling my catalytic converter?

    This is a question for those of you who have removed the cat.

    Does it improve performance and/or fuel economy noticeably? Does it make the car sound like a chainsaw?

    I have mixed feelings due to the fact that I know which pollutants are reduced by the converter and I don't seek to pollute more than my fair due. I'm not judging, just curious.

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    3Geez Veteran Rendon LX-i's Avatar
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    Re: Drilling my catalytic converter?

    Doesn't improve shit. If anything it will decrease. On a stock A20 you won't fell crap unless your high comp or boosted. If. On of the above youll lose back pressure with is bout 1hg an any tampering with a stock system on a stock motor is fail . Unless its clogged i would leave it. Or cut an replace with pipe. K bye


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    Re: Drilling my catalytic converter?

    What rendon said

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    LX User vteckiller's Avatar
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    Re: Drilling my catalytic converter?

    Quote Originally Posted by Rendon LX-i View Post
    Doesn't improve shit. If anything it will decrease. On a stock A20 you won't fell crap unless your high comp or boosted. If. On of the above youll lose back pressure with is bout 1hg an any tampering with a stock system on a stock motor is fail . Unless its clogged i would leave it. Or cut an replace with pipe. K bye
    So increasing air flow will actually make a car shitty.. And of course youll lose backpressure its called Scavenging power So you have to make or by a device to Compensate for the lack of back pressure while allowing more flow... who would have thunk.. i though at the factory the honda ppl tuned these cars to the max so anything you do to em would be like.. fail.. just fail.. don't even touch the honda anything.. its fail?
    Last edited by vteckiller; 12-16-2011 at 12:24 PM.
    LIFE IS SHORT, DRAG IT OUT!

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    Re: Drilling my catalytic converter?

    One of the best narratives I read about increasing HP compares your engine to an air pump. You have to basically do three things to increase the volume of air going through the pump (increasing the air volume goes hand-in-hand with the HP increase).

    Get more air INTO the pump (improve intake flow)
    Get more air THROUGH the pump (i.e. higher lift cam, turbo, larger piston bore)
    Allow more air OUT of the pump (better exhaust flow)

    So, barring a poor OEM design, our engines should already have decently matched throughput. If you increase any one of the parameters above without increasing the others you will do very little toward achieving your goal and, as Rendon states, you will probably end up worse off.

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    LX User vteckiller's Avatar
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    Re: Drilling my catalytic converter?

    But reading is not knowledge. im not saying im right, and im not saying you're wrong. but as long as you aint going like 3-4inch thats a HUGE difference and Obviously not worth it.. you gotta find the happy medium.. you think honda had in mind performance and power in mind when they make there cars? there after saftey, reliability, dependability, ect ect.. then tuning to a safe tune.. every car has been tune to factory specs.. witch are from low to medium tuned.. you still get back pressure from the exhaust and the silencer.. they make a * plug * device so you don't ruin your engine and lose scavenging power.. Who knows i could be wrong all together... thanks all!
    LIFE IS SHORT, DRAG IT OUT!

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    Re: Drilling my catalytic converter?

    Quote Originally Posted by vtechkiller View Post
    So increasing air flow will actually make a car shitty.. And of course youll lose backpressure its called Scavenging power So you have to make or by a device to Compensate for the lack of back pressure while allowing more flow... who would have thunk.. i though at the factory the honda ppl tuned these cars to the max so anything you do to em would be like.. fail.. just fail.. don't even touch the honda anything.. its fail?
    these cars are horribly choked and restricted, Honda didn't care about performance but about fuel economy and emissions. Ask anyone on here who has a webber and a decent exhaust system, makes a world of difference, this is a pretty decent sized engine by Honda standards. If you want a cat because you feel guilty, get a high flow one. In the general scheme of things the small number of these cars on the road, combined with the few miles they are driven, is not going to contribute much to the overall pollution issue. if there were still a million of them on the road it would be different. Having your car tuned properly and maintained will help more then anything. The factory exhaust is terrible, if you replace it and don't have any modifications, a mandrel bent 1 3/4 system and decent high flow muffler will help some, or at least be there for when you do any performance upgrades. Since you have any LXI you have a lot of options in making power, a lot of people on here have made pretty fast cars out of them.
    Last edited by lostforawhile; 12-16-2011 at 02:33 PM.

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    Re: Drilling my catalytic converter?

    Mine, though totally stock, is still too fast for the pokey idiots who drive around here. SAD.

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    3Geez Veteran Rendon LX-i's Avatar
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    Re: Drilling my catalytic converter?

    Quote Originally Posted by vtechkiller View Post
    So increasing air flow will actually make a car shitty.. And of course youll lose backpressure its called Scavenging power So you have to make or by a device to Compensate for the lack of back pressure while allowing more flow... who would have thunk.. i though at the factory the honda ppl tuned these cars to the max so anything you do to em would be like.. fail.. just fail.. don't even touch the honda anything.. its fail?
    HUH? what you said made no since. Theory on exhuast flow. "if you cant shit what you eat your going to have problems" Point beening doent matter if you slap on a intake exhaust header. That car is not meant for performance so in your case Cutting the cat is Not going to increase Performance doesnt matter how much air is flowing . All your doing is incresing the tubbleNESS of the exhaust flow on a stock system THUS LOSS OF POWER. you have to complenty redo your head to make these A20s scream OR in my case i added a cam and ported the shit out of my stock head also the complete exhaust system 2 1/4 mendrel bend. Following a Cold air intake. Made a difference hands down.

    I just recently cut my cat in my Ef sedan. an the outcome......... MADE no damn difference just made it louder.

    In no means im bashing im just stating the facts. I telling you what i was preched. Take it as you want but thats my .02 cents.

    Remember If you cant shit what you eaT problems accure.


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    LX User vteckiller's Avatar
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    Re: Drilling my catalytic converter?

    It was actually me being an ass cause you said taking out the cat will actually decrease performance ect ect.. you said it bro..
    LIFE IS SHORT, DRAG IT OUT!

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    3Geez Veteran MessyHonda's Avatar
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    Re: Drilling my catalytic converter?

    Quote Originally Posted by DBMaster View Post
    This is a question for those of you who have removed the cat.

    Does it improve performance and/or fuel economy noticeably? Does it make the car sound like a chainsaw?

    I have mixed feelings due to the fact that I know which pollutants are reduced by the converter and I don't seek to pollute more than my fair due. I'm not judging, just curious.
    i installed a "high flow cat" into the white coupe and it just made me lose mpgs because the car reved a bit faster. its just the butt dyno thinking you gained hp when you just punch it.
    Quote Originally Posted by Rendon LX-i View Post
    Doesn't improve shit. If anything it will decrease. On a stock A20 you won't fell crap unless your high comp or boosted. If. On of the above youll lose back pressure with is bout 1hg an any tampering with a stock system on a stock motor is fail . Unless its clogged i would leave it. Or cut an replace with pipe. K bye
    i have a cat on my b18c5 motor i still made 159whp.

    Quote Originally Posted by Rendon LX-i View Post
    HUH? what you said made no since. Theory on exhuast flow. "if you cant shit what you eat your going to have problems" Point beening doent matter if you slap on a intake exhaust header. That car is not meant for performance so in your case Cutting the cat is Not going to increase Performance doesnt matter how much air is flowing . All your doing is incresing the tubbleNESS of the exhaust flow on a stock system THUS LOSS OF POWER. you have to complenty redo your head to make these A20s scream OR in my case i added a cam and ported the shit out of my stock head also the complete exhaust system 2 1/4 mendrel bend. Following a Cold air intake. Made a difference hands down.

    I just recently cut my cat in my Ef sedan. an the outcome......... MADE no damn difference just made it louder.

    In no means im bashing im just stating the facts. I telling you what i was preched. Take it as you want but thats my .02 cents.

    Remember If you cant shit what you eaT problems accure.
    if you remove your car the car just smells like raw gas untuned

    1989 Honda Accord LX-i
    B18c1 swap since 7/2011
    175whp and 132tq
    Redzone tuned

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    DX User rocketman's Avatar
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    Re: Drilling my catalytic converter?

    Quote Originally Posted by CzEcHy View Post
    Try finding a resonated test pipe for an 86 to 89 accord, I've had 0 luck.
    Hey Czechy . . google "TuningPros" . . where I got the test pipe for our Civic. They list a ton of test pipe applications for the Accord . . . one I see is a test pipe for 1990-91-92-93 Accord for $11.90. Sorry I can't post a link. Let me know if you can't find it. Rocketman

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    3Geez Veteran Rendon LX-i's Avatar
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    Re: Drilling my catalytic converter?

    Quote Originally Posted by MessyHonda View Post
    i installed a "high flow cat" into the white coupe and it just made me lose mpgs because the car reved a bit faster. its just the butt dyno thinking you gained hp when you just punch it.


    i have a cat on my b18c5 motor i still made 159whp.



    if you remove your car the car just smells like raw gas untuned
    I didn't know there was a car in a car! Lmfao. Fucking jessy.

    Yes I agree on the hp. A cat won't change how a car proforms that's why I stated facts. School taught me a lot.


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    cygnus x-1's Avatar
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    Re: Drilling my catalytic converter?

    Quote Originally Posted by Rendon LX-i View Post
    Yes I agree on the hp. A cat won't change how a car proforms that's why I stated facts. School taught me a lot.

    Unless it's plugged up. But yeah, as long as the cat isn't a flow restriction, removing it won't help performance.

    Regarding exhaust system backpressure, I would suggest reading these articles:

    http://www.team-integra.net/forum/bl...st-tech-i.html

    http://www.team-integra.net/forum/bl...sure-area.html


    Under no circumstances do you want BACKpressure in an exhaust system. What you want is a forward pressure, a vacuum, to suck the exhaust gasses out.

    C|

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    Re: Drilling my catalytic converter?

    i will say that in my civic removing the cat decreased my gas mileage considerable, roughly 10%. that being said it definitely "feels" a bit more peppy, could just be the sound it makes, who knows. I do prefer leaving some kind of cat in place but they're so damn expensive compared to a test pipe.

    the reason czechy said he's trying to find a test pipe made for the accord is probably because he wants something with flanges to bolt up without cutting and welding or c-clamping.
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