Long story, I'll try to make this short, 2000 E250 5.4L What would or could happen if the catalytic converter was removed from the exhaust system?

 

- More power

- More Sound

- Better MPG

- If you have an O2 sensor to monitor catylist efficiency after the cat you will probably get the CEL on.

- Its illegal (Federal Law), but not enforced.

 

Short answer, probly won't be able to pass inspection. Sucks though.

 

By removing the catalysts the exhaust will flow easier which should give you more Hp at higher RPM but you may lose some of the low end torque due to the change in flow charateristics.

 

Thanks for all the responces

 

It will be louder, that is all. Your CEL will come on, which reduces the vehicle resale value and prevents you from knowing when a real problem arrises. If you try to sell the vehicle, you can sell it to another individual, but if you want to trade it in, the dealership will have to dock you the value of the missing converters, because they will have to restore it (all cars sold at registered dealerships must pass federal emissions.)

My advice is to use a good high flow converter. It won't be as loud as a straight pipe, but it is legal, it will keep the light off, and it will not hamper the performance noticeably. Simply removing a converter will not make that much difference to the performance unless it was plugged. The exhaust is a system, and it will only offer as much performance as its weakest point, so to really make a significant difference in the performance, you would need to redo the entire exhaust, not just one component. The single greatest bottleneck in most systems is the factory muffler. You will notice more power gains with replacing that than you will with any other single component in the system. The second greatest power robbing component is the factory manifold. So unless you already have headers and a performance catback system I don't think you will notice a measurable increase in power, only a noticeable increase in sound level (which are often confused).