Hey guys, quick question. I have a friend swearing to me that an underdrive pully will increase hp at the wheel by at least 10. I am still a newbie at the whole DIY vehicle thing, but I have not heard of this yet. Anyone put one of these things on? Is it worth doing? So far, you cats have given me WAY better advice than my friends, so I look forward to hearing from ya!
Thanks in advance!

 

ehhh. I did this on a ranger once. didnt notice anything really. Dont change the pulley on the alternator or you can have charging issues. Best thing to do pulley wise is a efan swap.

 

I've run them on a couple of different vehicles. They worked best with an electric fan. I liked running them on my Mustang. Don't expect anything drastic though.