I have a 1998 ford explorer SUV. I took off my muffler for better sound will it affect my motor?

It pretty much gets really loud.

It will be really loud and probably not in the way you want. You should check out after-market mufflers if you want your car to produce more noise.

No affect. Maybe a little better throttle responce/milage. But what's with the noise? You really want that? Go aftermarket like above poster said. Whatever you do, leave the cat and 02 sensors alone. That WILL affect the motor.

A properly tuned muffler generally will give you better stop light to stop light power vs no muffler at all. It might also be illegal to run without a muffler because of the noise that it produces.