So, i have a 88 bronco II, 2.9 v-6. It has the two cats...I have a magnaflow direct fit cat. i plan on installing soon, but i am still a little curious. What happens if you run no cat besides causing global warming? I have seen something called "test pipes" offered for this, and they say "for racing use only". Do you really gain any HP or TQ from removing the cat? Like i said, i am installing a cat. converter, and i understand that it is illeagal to remove it, i am just curious what it would do without it.

 

I dont no the laws in the states but here in canada we can cut them off and run it without. My experince with cats they tend to get plugged up over the years and decrease gas mileage and power ive had a few vehicle took them off and they have run alot better and seen a slight bit better in gas consumption.

 

hmm just have a question that goes along with this..if i remove my cat (87 bII 2.9) will i have to reprogram anything and or will it through the o2 sensors out of wack?

 

You could gain about 5-8 horsepower removing the converter but you will get alot louder and raspier exhaust if you have a performance muffler (flowmaster,magnaflow,dynomax,etc.). If its your daily driver id put the magnaflow cat on just to be safe you know how the law is. Magnaflow cats are very high flowing so youll barely notice any difference over a test pipe, plus you get a cleaner smelling exhaust and mellow sound with a performance muffler.

 

Nope on OBD1 systems it uses only one oxygen sensor which is before the cat.conv. The cat is not being monitored by the ECU

 

yeah, i did notice that my o2 sensor is before my cat also

 

Throw them away, just added weight.