Subject	SELLING: PEX Overdrive Water Pump Pulley w/ Belt $95 shipped
Posted by	Alan(NJ) on January 02, 2008 at 5:55 PM
	This message has been viewed 231 times.
	Screen Name: Alan(MD) Real Name: Alan Acosta Phone: 201-660-0417 Location: Waldorf, MD 20601 USA E-mail: AlanAcosta83@gmail.com Research Alan(MD)'s post history
Message	Description: A pulley for the water pump that has a 15-20% smaller diameter (stock sizes TT= 120mm, NA= 130mm), which results in the belt driving the water pump faster than if the belt was driving the stock water pump pulley. Also, as the standard clutch fan is attached to this pulley, the fan's rotational speed is increased, drawing more air through the radiator. Why is it needed? Engine idle is a particularly stressful time for an engine, oil pressure is low, airflow through the engine bay is almost non-existent, air flow through the radiator is low, and coolant flow is minimal. Combine this with a warm or hot day, + with the added strain of your air conditioner, your cooling system is put under pressure. Then you buy an Under Drive Crank pulley to UP THE POWER, which slows down the water pump and clutch fan by up to 20%, and the ability of the engine to keep cool is right at it's limits. On top of that, with so many FMICs around now, it can all trap in heat. Coolant temps rise at idle by a few degrees anyway, but the stock temperature gauge never tells you this. Since installing my UD crank Pulley, the temps run higher across the board, but at idle, with the Air conditioner on, on a 79 degree day, my coolant temps would slowly rise to about 205 degs, whereas before the UD crank pulley was installed, the coolant temperature would stay around 181 degrees. After installing the pulley the temps have returned to normal. Developed in high temperature summers of Australia the PEX Water pump pulley addresses a cooling problem that can surface when you install a Unorthodox Racing (or similar diameter) under drive crank pulley. When you install a smaller then stock sized aluminum pulley you reduce not only the speed @ which the water pump turns @ a particular RPM but also the speed of the radiator fan. In doing so you doubly reduce your cooling capabilities in the process. This change is not always perceived by the casual driver because the temperature gauge on the Z32 is not linear, it tends to hover around the 8-9 o'clock mark during most street use. However the effect of the installing a smaller then stock pulley can be seen if you use nProbe/Consult/Hardware or similar data logging software/hardware - temeratures rise across the board but esp. at stop & go idle and at high load / track conditions. The solution - PEX of Australia has introduced a overdrive pulley for the water pump to be used in conjunction w. a smaller then stock main crank pulley. Their pulley is about 15% smaller then a stock sized Twin Turbo water pump pulley and returns the water pump & fan speed to the same amount of circulation per engine speed as the Nissan engineers intended. On modified or track driven cars that are pushed to their cooling limits this can be answer to maintaining proper cooling system performance and keeping your motor out of the red. *all information/description and picture was copied from Bernie (Nova)
Follow Ups	PEX Overdrive Water Pump Pulley w/ Belt $95 shipped - Alan(NJ) 17:55:44 01/02/08