gutting the cats
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From: Aberdeen, SD
gutting the cats
Yeah I have a 1990 F-150 with a 300 I-6. I wanna gut the cat, and I think the other thing on there is a resevoir or sometin. Would it bother any sensors or anything? I wanna straight pipe it if its not too loud, and if it is I wanna put on a glasspack. thanks
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From: Somewhere between San Diego and Phoenix
Keep in mind that gutting or removing cats is a violation of federal emissions laws. You will have to deal with the O2 sensors or you will get a check engine light.
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that truck's obd I so you don't have to worry about o2 sensors because it only has one.you just have to worry about actually passing emissions.that's the thing about new vehicles,you can use the obdII emission checks to you advantage by just tricking the downstream o2 sensor.but older models with obdI you actually have to make it pass.so,you'll have to keep that in mind.you could try goin through with just a piece of pipe in place of the cat and make sure it will pass.they'll tell you if you failed just because you don't have a cat.then just gut it and throw it back on.
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From: minnesota
just my 2 cents but true duals on a i6 dont sound too good....i kno a couple people that had explorers and tried numerous setups such as true duals... glass....flowmaster..... and so one and what seemed to be best was to buy oversized cats off of summit racing and have those installed then go with a 2in 2 out flowmaster. that was what me and my friends liked best.
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well,there isn't really any sense in puttin true duals on a I-6 since it only has one bank and you can't really put true duals on it because of that.and i'm not sure but i don't think any explorers had a 300 I6 unless you're talkin about an f-150 explorer.i don't think they sound that bad myself.v-6's dualed out sound queer as hell but i6's have alot deeper tone.
Last edited by way fast witey; Nov 23, 2004 at 11:02 PM.
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yeah,like i said 99% of v-6's do sound like crap when you can hear em at all.but i-6's sound almost like v-8's at idle with straight pipes and sound pretty good.if you run 2.5 pipe all the way out and maybe a y pipe to simulate duals and give it a little deeper tone with like 3 or 3.5 tips it'd probably sound pretty good.
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well,you put split headers on an obd engine and what are you gonna do with the o2 sensor?the computer will only know how to read one bank.so unless you ran em back into one,making the whole process useless,it'd run like crap.and that alot more work for not much more gain.unless you're runnin a highly modified i6 that wouldn't do much more than just throwin a y on it.long tube headers sound good on em.
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From: Oklahoma
Originally posted by way fast witey
well,you put split headers on an obd engine and what are you gonna do with the o2 sensor?the computer will only know how to read one bank.so unless you ran em back into one,making the whole process useless,it'd run like crap.and that alot more work for not much more gain.unless you're runnin a highly modified i6 that wouldn't do much more than just throwin a y on it.long tube headers sound good on em.
well,you put split headers on an obd engine and what are you gonna do with the o2 sensor?the computer will only know how to read one bank.so unless you ran em back into one,making the whole process useless,it'd run like crap.and that alot more work for not much more gain.unless you're runnin a highly modified i6 that wouldn't do much more than just throwin a y on it.long tube headers sound good on em.
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From: Aberdeen, SD
So basically there is no way to bypass the sensor? I was going to take off the cat and res. the other day and put a pipe inplace of it, but I saw the sensor and didn't want to mess it up or anything.
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no,what i'm sayin is you don't have to bypass the sensor on obd I.you'd only have to mess with the sensor on obdII vehicles.but if you have emissions tests i wouldn't do it unless you're prepared to go back and put a new cat back on if you don't pass.
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From: Lost some where in the middle of the Ozark Mountains!
First... yes you can buy 50 state legal dual headers for most '04 or older I6, V6, 4Cyl vehicles "Some will still fit on some '05's if vehicle design did not change much like the new F series trucks did, but those will be out soon too I'm sure, and 04's may work if the header design even changed on the F series". The headers come with all of the sensor holes already drilled and tapped for you as required per application, as well as all the heat exchanges, exhaust temp sensors and all other misc. plumbing for the newer rides. But most O2 Sensors are placed on the pipe after the collector anyway so usually it is not on the header assembly itself. If your installing headers then it is likely you are putting more air through the top too the tolerance of the O2 is very large so as long as your shoving 1/2 again as much air through then the O2 will never know it is only reading 1/2 the system. The after market performance industry will always keep up and provide us with tried and true performance and headers are by no means obsolete out of style or old school. Heck even the rice burners are installing them, I dread the day that they can get a performance part that we can not, much less something that us American Muscle guys originated and perfected such as headers.
Just for S&G's lets do a worst-case scenario tech seesion.
They started emissions control in 1981, so lets say you have a header for an 1980 AMC 4.0 I6 like found in Jeep vehicles and you want to place it on an 1987 AMC 4.0 I6 which does have emissions control. I can not remember the sizes as it has been several years since I did this one. But simply wrap 1/4 thick steel plate approximately 2"x2" square around the pipe on chosen location and weld it 360 degrees, measure the diameter of the O2 sensor, drill a hole with appropriate drill bit, tap with a NPT tap, and install the sensor. Or take it to any descent muffler shop and they can do this all for you. They should already have all the bits and taps on hand as the holes often get stripped on these anyway "especially stock" and they must repair it.
In theory the same principle would apply to my 5.4L, which is a 351 Windsor block and heads if I took an old 1972, 351 Windsor header and it would clear the cross members, steering, etc. then it could be drilled and tapped as needed to work like oem except better. But I think I'll just buy a new one for it to make sure it clears everything and looks better.
My question though, I plan to "deactivate" the cats on my '00 5.4L Triton. Other than unplugging the check engine light how could I contend with the 2nd and 4th O2 Sensor(s) problem?
Note: Sniffer test are not implemented for vehicle inspection here yet, only visual! I will address that issue when/if the need arises but it has been inspected for the next 2 years anyway so will be fine for a couple.
Just for S&G's lets do a worst-case scenario tech seesion.
They started emissions control in 1981, so lets say you have a header for an 1980 AMC 4.0 I6 like found in Jeep vehicles and you want to place it on an 1987 AMC 4.0 I6 which does have emissions control. I can not remember the sizes as it has been several years since I did this one. But simply wrap 1/4 thick steel plate approximately 2"x2" square around the pipe on chosen location and weld it 360 degrees, measure the diameter of the O2 sensor, drill a hole with appropriate drill bit, tap with a NPT tap, and install the sensor. Or take it to any descent muffler shop and they can do this all for you. They should already have all the bits and taps on hand as the holes often get stripped on these anyway "especially stock" and they must repair it.
In theory the same principle would apply to my 5.4L, which is a 351 Windsor block and heads if I took an old 1972, 351 Windsor header and it would clear the cross members, steering, etc. then it could be drilled and tapped as needed to work like oem except better. But I think I'll just buy a new one for it to make sure it clears everything and looks better.
My question though, I plan to "deactivate" the cats on my '00 5.4L Triton. Other than unplugging the check engine light how could I contend with the 2nd and 4th O2 Sensor(s) problem?
Note: Sniffer test are not implemented for vehicle inspection here yet, only visual! I will address that issue when/if the need arises but it has been inspected for the next 2 years anyway so will be fine for a couple.
Last edited by PSS-Mag; Dec 21, 2004 at 07:49 PM.
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From: Seabrook,NH
The current cats are pretty free flowing. You will not gain anything by defeating or destroying them. Leave them alone and keep our air clean. They have done tests that show our cats are not an issue. TrucksTv and Two guys garage both showed how free flowing they are. More improvement is gained by a catback and headers.
From Mike Troyer:
From Mike Troyer:
Don't take this response personally, OK?
I say that up front simply because this is one of my "pet peeves" as a tuner & F-series performance specialty company, so I'm going to be perhaps a bit "blunt" in my response - so keep in mind that this isn't "aimed" at you specifically, but instead is just in general to anyone thinking about removing or gutting their factory cats.................. & thanks up front for your understanding on that!
OK, with that preface out of the way..............
Catalytic converters are not "ghey" by any stretch of the imagination - and anyone that removes or "guts" their catalytic converters is doing something highly illegal, as well as polluting the air everyone else has to breathe. Nobody has the "right" to do that, nor will we knowingly help anyone trying to do that.
Here's some quick background that (I hope) will help everyone to understand this a bit better......................
Many years ago, catalytic converters *were* pretty restrictive and they did cost a significant amount of power and fuel economy - back when they came out in the 1975 model year, and continuing on for well over a decade, they were rather restrictive. Well, that hasn't been true for about a decade or so now, that is a thing of the past - and some people just aren't aware that this has changed, so we still see people wanting to gut or remove their cats. People see the 4 cats on these trucks and think "good grief, 4 cats, that's twice as much restriction!!" And that would be a seemingly reasonable assumption upon cursory examination - but wrong answer in reality.
The 4 stock cats on these 1997 & up F-150's actually flow pretty well for their application, certainly better than a single monolithic unit could. In fact, we do not advise upgrading them for performance purposes with a pair of high-flow Magnaflow cats (the *ONLY* aftermarket catalytic converter we will use on these trucks) unless the vehicle has a supercharger installed (or other major mods yielding big power gains) basically, as the power gained compared to the cost involved to do it right is pretty small.
The power gains from removing the 4 factory cats and replacing them with a pair (2) Magnaflows (or straight pipe) is about 5 HP at STOCK power levels in the F-150, and then it goes up from there as you do more mods to increase engine power. With a supercharger installed, you may see as much as 10-12 HP or a bit more from installing high-flow cats on a motor making say, 400-500 flywheel HP.
NEVER gut, strip or remove ANY of the factory catalytic converters without replacing them with properly functioning units that provide a clean exhaust that will pass a "sniff" test at the tailpipe for that model year vehicle and restoring proper downstream O2 sensor & OBD-II systems operation - please. Doing so is highly illegal in all 50 states, contrary to the claims from some that certain states - say, South Carlina, or Florida, or Arizona (or any other state) saying that is "OK." NO state says that it's OK to remove or gut the cats, although some places don't do much of an emissions inspection, unfortunately.
Removing or gutting cats just pollutes the air for everyone else to breathe, and results in very small power gains - not something you want to do.
In OBD-II vehicles, you are supposed to get a "check engine" light (or Service Engine soon, the "SES" light, same thing) on the dash if you remove or gut the cats - now we have seen that there are a few vehicles that do not throw a hard code for this as they should, but by and large, YES, removing or gutting the cats DOES result in "screwing up the computer," as you put it - and what I mean by that is that yes, doing that is supposed to result in a check engine light - a hard DTC being thrown by the PCM.
Yes, it certainly is true that we can turn off the downstream O2's in a custom tune in either the 9100 or the 6600, and completely circumvent those problems - but WE WILL NOT DO THAT on any program that I feel or suspect is going to be used on the street. Why? Because it's *illegal*, and in that situation is done only to aid in breaking the law by illegally removing the catalytic converters. The *only* time I will turn off the downstream O2's is on a or "drag race" or some other type of "maximum performance" or "racing" or "dyno" program, meaning a tune that is NOT intended to be used on public roads. So in a 4-program custom chip, we might load ONE program that does that, just so they can get a good A/F reading on the dyno or while datalogging a pass at the track, etc., but we're not going to do all the tunes like that, each vehicle that is going to be driven on the street has to have a tune that is going to pass tailpipe emissions for that vehicle's model year.
The main thing you need to know is simply that your factory cats (unless they are actually clogged, which is rare) aren't costing you any significant amount of power, mpg or performance - that stopped being the case over a decade ago, so I'd suggest not removing them.
Just FYI, gang, & hope that info helps a bit..............................
__________________
Mike Troyer
Troyer Performance/Performance Products, Inc.
Truck & SUV Performance Specialists
Supercharging & Custom Tuning Experts - America's Oldest Superchips Distributor & 1st Superchips Custom Tuning Dealer
Web Site: TroyerPerformance.com
(540) 862-9515
Email: Sales@TroyerPerformance.com
National F-150 Online Rally Event Organizer
I say that up front simply because this is one of my "pet peeves" as a tuner & F-series performance specialty company, so I'm going to be perhaps a bit "blunt" in my response - so keep in mind that this isn't "aimed" at you specifically, but instead is just in general to anyone thinking about removing or gutting their factory cats.................. & thanks up front for your understanding on that!
OK, with that preface out of the way..............
Catalytic converters are not "ghey" by any stretch of the imagination - and anyone that removes or "guts" their catalytic converters is doing something highly illegal, as well as polluting the air everyone else has to breathe. Nobody has the "right" to do that, nor will we knowingly help anyone trying to do that.
Here's some quick background that (I hope) will help everyone to understand this a bit better......................
Many years ago, catalytic converters *were* pretty restrictive and they did cost a significant amount of power and fuel economy - back when they came out in the 1975 model year, and continuing on for well over a decade, they were rather restrictive. Well, that hasn't been true for about a decade or so now, that is a thing of the past - and some people just aren't aware that this has changed, so we still see people wanting to gut or remove their cats. People see the 4 cats on these trucks and think "good grief, 4 cats, that's twice as much restriction!!" And that would be a seemingly reasonable assumption upon cursory examination - but wrong answer in reality.
The 4 stock cats on these 1997 & up F-150's actually flow pretty well for their application, certainly better than a single monolithic unit could. In fact, we do not advise upgrading them for performance purposes with a pair of high-flow Magnaflow cats (the *ONLY* aftermarket catalytic converter we will use on these trucks) unless the vehicle has a supercharger installed (or other major mods yielding big power gains) basically, as the power gained compared to the cost involved to do it right is pretty small.
The power gains from removing the 4 factory cats and replacing them with a pair (2) Magnaflows (or straight pipe) is about 5 HP at STOCK power levels in the F-150, and then it goes up from there as you do more mods to increase engine power. With a supercharger installed, you may see as much as 10-12 HP or a bit more from installing high-flow cats on a motor making say, 400-500 flywheel HP.
NEVER gut, strip or remove ANY of the factory catalytic converters without replacing them with properly functioning units that provide a clean exhaust that will pass a "sniff" test at the tailpipe for that model year vehicle and restoring proper downstream O2 sensor & OBD-II systems operation - please. Doing so is highly illegal in all 50 states, contrary to the claims from some that certain states - say, South Carlina, or Florida, or Arizona (or any other state) saying that is "OK." NO state says that it's OK to remove or gut the cats, although some places don't do much of an emissions inspection, unfortunately.
Removing or gutting cats just pollutes the air for everyone else to breathe, and results in very small power gains - not something you want to do.
In OBD-II vehicles, you are supposed to get a "check engine" light (or Service Engine soon, the "SES" light, same thing) on the dash if you remove or gut the cats - now we have seen that there are a few vehicles that do not throw a hard code for this as they should, but by and large, YES, removing or gutting the cats DOES result in "screwing up the computer," as you put it - and what I mean by that is that yes, doing that is supposed to result in a check engine light - a hard DTC being thrown by the PCM.
Yes, it certainly is true that we can turn off the downstream O2's in a custom tune in either the 9100 or the 6600, and completely circumvent those problems - but WE WILL NOT DO THAT on any program that I feel or suspect is going to be used on the street. Why? Because it's *illegal*, and in that situation is done only to aid in breaking the law by illegally removing the catalytic converters. The *only* time I will turn off the downstream O2's is on a or "drag race" or some other type of "maximum performance" or "racing" or "dyno" program, meaning a tune that is NOT intended to be used on public roads. So in a 4-program custom chip, we might load ONE program that does that, just so they can get a good A/F reading on the dyno or while datalogging a pass at the track, etc., but we're not going to do all the tunes like that, each vehicle that is going to be driven on the street has to have a tune that is going to pass tailpipe emissions for that vehicle's model year.
The main thing you need to know is simply that your factory cats (unless they are actually clogged, which is rare) aren't costing you any significant amount of power, mpg or performance - that stopped being the case over a decade ago, so I'd suggest not removing them.
Just FYI, gang, & hope that info helps a bit..............................
__________________
Mike Troyer
Troyer Performance/Performance Products, Inc.
Truck & SUV Performance Specialists
Supercharging & Custom Tuning Experts - America's Oldest Superchips Distributor & 1st Superchips Custom Tuning Dealer
Web Site: TroyerPerformance.com
(540) 862-9515
Email: Sales@TroyerPerformance.com
National F-150 Online Rally Event Organizer
Last edited by Norm; Dec 22, 2004 at 09:30 AM.