SOTP, I definetely felt a torque increase. But, thats not why I'm writing about it. Since day 1, Ive always had what felt like an internal engine imbalance. Even with the Steeda underdrives I used to have, my engine would vibrate at about 2300 rpm when parked in neutral. Ive read about a few others who also seemed to have this issue. Well, with these new pulleys, that vibration is totally gone. Looks like the fluid thing is doing its job. These arent piggyback's BTW.