I am thinking of installing a set of underdrive pulleys on my truck to attempt to get a few more ponies and possibly gain better fuel milage, but I am not seeing a lot of kits out there for the cummins, but maybe I am looking in the wrong places. If anyone has any brands or websites I can get a quality set let me know. I'm also curious as to how noticable the power was after installing them. I have used them in the past on a gas burner and they were by far the best bolt on mod I ever did....

 

You do not want to do this... you will not benefit from it and it will reduce performance of your acc.

 

I agree, not a good idea for a daily driver. On average you turn lower RPM's then a gasser so if you lower the accessory speeds from that you might have some issues with hard steering/brake pedal (my biggest concern), and lower water flow through the pump. Charging I don't think would be a big deal, but who knows.

 

Both the PS pump and vacuum pump are gear driven, so underdrive pulleys would not affect that. Just charging, A/C and fan speed.

 

Ya I guess so huh? I've been driving my jetta too much...