What will removing the Catalytic converter do?

Question

I have a 1999 dodge dakota 3.9L v6 with a cold air intake and flowmaster 40 dual's. everyone's telling me i should remove the cat, for more hp, but i've heard this kills low end torque. what exactly will it do to and for my truck if i do this? and i know its illegal so everyone thats gonna criticize me for doing this... just dont bother to respond to this question.

Answer 1

The catalytic converter does not restrict flow as much as people think they do. In days past they may have restricted the exhaust flow more, but not so much any more. The only reason to replace one is if the one on your vehicle is plugged up or the insides are broken loose, then it will have a restriction in the exhaust (just FYI, emissions equipment is covered under an 8 year 80k mile warranty).

Removing it will not give a noticeable improvement in power, and worst case it may even cause engine damage or cause running problems.

The check engine light will come on, oxygen sensors may read incorrectly, causing a too-rich or too-lean fuel mixture, which can in turn cause internal engine damage. More pollution will enter the atmosphere than otherwise would be burned off in the converter.

They do make high-flow converters for performance exhaust systems, but it won't make a noticeable difference on yours with the improvements you've done, but that'd be the way to go if you insist on changing it out.

Also, if you have emissions or equipment inspections where you live, or if they bring them in, or if you move to an area that does, it will not pass inspection.

You will have to do this on your own since exhaust shops won't as fines for removing or altering converters are huge.

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Sorry Doug K, but anyone who has over 20 years experience in the automotive industry should know that it's a FEDERAL violation to remove or alter a catalytic converter.

Answer 2

Well, it is only illegal in places that enforce smog inspections. If you live in a place that does not require yearly smog inspections, then you can remove it. If your truck has two O2 sensors per side, then you may get a check engine light because the second sensor checks to see how well the cat is working, and if it isn't there it will sense it. I this is the case on your truck, I would just get high flow cats from Summit. If you are running dual exhaust and two cats, then make sure to run a crossover pipe, as this will significantly increase exhaust scavenging and bring up low end torque. If your exhaust Y's down into a single cat, and Y's back out to duals, then get a large diameter cat like 2.5" or 3". The single cat will act like a crossover pipe in a true dual setup, and will keep your torque curve nice and healthy.

Answer 3

Mark B has the best answer for you. Please remember it IS illegal by Federal laws to remove the catalytic converter on a street use vehicle. And if you are in a state that does inspections, you could also be fined, and in extreme cases, have the vehicle impounded till you have a correct catalytic converter installed on it. Good luck.

Answer 4

Removing the cat will only cause your computer to throw codes...... get a high flow cat converter off of ebay. A universal is only $50, I just bought one for my Durango.

Answer 5

either get a high flow cat, or if you don't need one to pass the visual and sniff test, you can get an O2 simm to plug in to fool your computer from getting an error code.

Answer 6

It will free up some horse power BUT will you be able to get a state inspection?