Why type of effects pedal can make a Wah pedal sound really sick, or boost the Wah?

I have a Dunlop, Jimi Hendrix signature wah wah pedal, and a Kirk Hammet sig. wah pedal. They're not really what i expected though. Is there some other type of pedal that i can use to amplify the wah, and make it really sound like Metallica or Sixx am?