I was looking to remove the cat from my 99 F250 with the 5.4l. What kind of a power differance will this make? Has anyone here done this?

 

It will give you some power increase due to the free-er flowing exhaust...but I doubt you will be able to notice it in the seat of your pants, unless you go with a full exhaust system (headers back).

 

You will need some simulators to replace your rear O2sensers. The truck will throw a check engine light without the sims. I doubt you will notice much difference with just removing the cats. Add headers , freeflowing mufflers & a tuner if you want more power

 

Superduties don't have rear O2 sensors. They are not required to have them, as their GVWR is too high.

 

There is one O2 sensor behind my cat(well where my cat was)

 

All OBD-II vehicles have o2 sensors behind the cats.

 

That is, if the SD is really OBD-II

My '01 V10 doesn't have a third O2 sensor. And, it's a CA emissions package, so go figure.

Look underneath. Any O2 sensors after the cat? You need a simulator or re-tune. No O2 sensors after the cat? Nothing special needed.

That's about the only way to decide if you need to fudge it or not.

Now back to the problem at hand: Why remove the cat? So you can get pulled over by DOT on the highway and get fined for it? Better yet, state troopers are being trained to check for emissions devices nowadays.

Even if your state doesn't do any smog checks or visual checks, you can get nailed by the DOT or state police (or the locals even ...).

I won't even go into my personal views on this...

But if you do remove it, you assume the risks too

 

What are simulators? Was thinking about taking the cats off of my 99 f-150... and where can you get them?

 

Why do you want to illegally remove emission equipment, it's like a $10,000 fine, why not replace it with a free flow aftermarket one and remain legal?