Quote from Zoomer, "...our best guess is that the car'* temps run 2 deg hotter than normal. We've dyno tested and found it gives 3WHP at 5800rpm."

This relates to the ZZP underdrive waterpump pulley. Somewhere there is word that the stock size waterpump pulley caused cavitation, hence the UD pulley "should" allow the engine to run cooler. Anyone have a source on this if it exists?

Either way, if the car is running 2 deg hotter, I'm glad I drilled my 180-stat.

Hope you all find this info helpful.

Would the underdrive pulley cause the water pump to spin faster or slower?

i dont think it makes much of a difference. Our cooling systems are capable of keeping our cars pretty cool. If you dont believe me take out your tstat and see how much it warms up.


How do they test if the pump was cavitating?

huh? if you take the tstat out, it will run cooler.

slower.

If cavitation was much of a problem, shouldn't we hear about more wp failures?