Aside from using a lighter CG10 steel pulley there is nothing available for the k11 such as lightweight or underdrive pulleys. To be honest the money is better spent toward the cost of a lighter flywheel or a remap from Ed.
if you have access to the machenery, you could make a aluminium crank pully fairly easily, i looked at it yesterday infact and i dont think theres tonnes of potential to lighten the standard steel one.
Aside from using a lighter CG10 steel pulley there is nothing available for the k11 such as lightweight or underdrive pulleys. To be honest the money is better spent toward the cost of a lighter flywheel or a remap from Ed.
x2 lightening the (bigger diameter) flywheel has far more effect, and i prefer to keep the stock 1.3 pulley (with its harmonic damper) because of posts about flywheel bolts coming loose on other nissan engines where the damper was removed
and the alternator can be underdriven np, with a 2x bigger pulley http://www.micra.org.uk/attachment.php?attachmentid=13884&stc=1&d=1260205519
Is there much weight diffrance in the cg10 to the cg13?
I've got a L&B flywheel and e-manage ect ect and I know most say there's not much to be gaind from it but all these little things add up to a bigger picture if you know what I mean?
dunno on the pulley mate (old p/s pulley maybe)
my waterpump has been fine with the idler removed (and a shorter belt) and you can run it with a lot less tension because there,s more belt/pulley contact (same with the alt)
you could fit a bigger one to the pump eh, or else electric ? http://www.micra.org.uk/attachment.php?attachmentid=13886&stc=1&d=1260209741