I have been hearing a lot lately about companies coming out with Underdrive pulleys and was wondering if anyone has any experience with these? I have my motor out and I think it would be a good time to throw one on.

Which companies are making them and what kind of gains are being seen? I have had these on some of my past vehicles and I know they do pick up some gains from the smaller circumference but have also heard of a lot of problems they cause. Is the factory pulley a harmonic balancer? Will these cause premature bearing wear? Will the alternator still put out full voltage?

 

Don, call BBi and talk to Betim. I've had this on my car for three years now.

 

Geez, I thought that was a Mustang mod j/k guys...

 

the one made by PD under drives the accessories and doesn't provide a full charge wit the alternator and such it was designed to slow the accessories on cars seeing real high rpms for long periods.

the EVOMS one is a lighter version of stock No accessory under drive AFAIK(they dont list it on the website and wont answer the phone to talk so cant get any more info )

i looked into it i would ask BBI which version theres is but i dont want my car not charging at idle we have enough electric issues, a lighter version of stock pulley id go with that.

the smaller under driven pulley also needs a new belt