According to my brother, not sure if i should believe him, but i think he is saying i have 2 on my 99 ford ranger 3.0 v6. When i do my exhaust this week, he said it would be better if i removed one(think he said the one closest to the rear) and that there is nothing to worry about. think he also said it would help get rid of some restriction and all, and be better for me. im sure you guys know alot more about this, so is this a wise idea? im getting a flowmaster 40 series installed sometime next week, si/do to rear bumper with stainless steel tips probably.

 

you may have 1, 2, 3, or 4... any and/or all of them can be removed in certain circumstances... my mustang had none when i was done with it,and it started with 4... the important thing is that there aren't any changes before the last o2 sensor... some vehicles have an 02 before the cat, and one after, this could be for each bank, or total together... anything after the last o2 sensor is helping emissions, but not power or performance... the only downside is, if you live somewhere with emissions testing, you very well could fail them, by removing the cat's... what i used to do on my mustang is rent a set of cats from a shop for $60 a day, which included removal and install of mine, and theirs (2 full installs and removals) which allowed just enough time to get the test done, and get back to the shop...

 

well i think he said that one i should remove is after the o2 censor. and when i did my tests and all, they plugged something into my computer in the front drivers area and that was it. only thing that got me was my gas cap and it was broken, so had to get a new one anyways

 

a leaky gas cap failed you on the emissions test?

 

i dont know what an emissions test is then haha, all i know is when i got my truck i did that test and got an inspection sticker. guessing they dont do emissions test here then.

 

yes, a leaky gas cap will fail you here also... they probably put a tube into your exhaust and ran the vehicle, generally on a device, similar to a dyno, so that it puts a load on the engine...

 

Removing the cat is illegal. If it came with 2 it will fail a visual inspection with one.

You will not see any gains of removing it, sound may change.

IMHO, if you have inspections leave it alone.

 

well never mind on all this now anyways. when we lifted the truck today for them to do my exhaust and all, we noticed that the o2 sensor was behind cat 2. so im screwed with that. i got to thinking though, and wasn't going to do it after all.

 

you can have an 02 sensor bung welded into the pipe that goes in place of the cat. thatll keep the sensor in the exhaust and keep your check engine light happy.

 

Yeah but then the engine doesn't know if its being efficient, It thinks its the picture of health but it could have a problem. Frankly I would have been surprised If the O2 sensor was between the 2 cats instead of behind both of them because its there to measure the efficiency of the entire system. You wouldn't see any gains by removing one of the cats anyways the 3.0l isn't pushing near the air that the cats can handle. Just get a cat back system, its cheaper, easier, and will give the truck a more mellowed out rumble.

 

idk much about this but someone was tellin me on mine i can gut the cats and put dummy loads and still pass emissions.

 

Leave your cats on and intact. You will not gain anything. Leave it all alone. Gutted cats will not pass a sniffer test.

 

usually if there is an o2 sensor after the cats, there is one before, the one before is to see if the engine is running right, the second does not change the way the motor runs, but makes sure the cats are working properly...

 

The plug going into the cabin isn't an emissions "test" per se. What the state plugs into your underdash is nothing more than a code scanner and in the case of some vehicles, a confirmation of the VIN or other serial number that's taken from the ECU and matched to the particular vehicle. A check engine light will fail you and a defective gas cap will set off the CEL.

The true emissions test is when they probe your exhaust.

 

a CEL should NOT make you fail... if you have something wrong with your air conditioner or a sensor is out, which would fail and cause LESS emissions, they can't fail you for that...

 

In CA if the check engine light comes on during the test or if it is on then it's an automatic fail.

 

wow, that's complete BS! do they hook a code reader up to the vehicle during the test, or is it just visual? you could always just remove the bulb, i've put burnt out lights in behind things like that to sell vehicles before

 

They hook up a code reader during the test. When the test is done the results automatically get sent to the DMV. Sucks but that's how they do it. The first smog test is done when the vehicle reaches 6 years old. They started to do random roadside smog checks but the state ran out of money so they got rid of that program alone with the smog refs. So if you get a ticket for no cats you can go to any shop to have them sign off on it.

 

that's ****ed! i know where i used to live, once a year, before you can renew your registration, you had to go through the smog test, they do an idle test, to check for HC, NOx, CO and one or 2 other gases/chemicals... if you pass that, they run your vehicle on a dyno type machine to 60km/h (40mph ish) and test for the same chemicals/gases they also do a gascap test

 

I didn't mean to burst your bubble.

 

no bubble, it's all good man

 

Does anybody know anything about hi-flow cataylic converters i was thinking about putting some on mine to replace the 3 that i have
any advice?

 

The cats that come from the factory on the Ranger are already hi-flow.

 

i have never heard of any truck coming stock with hi flow anything

 

all modern cars come with high flow catalysts.