http://www.toymods.org.au/4A-GZE_Tech.html
"The supercharger is a roots type unit, manufacturer is unknown at this time. The lower vane is driven by the pully and drives the upper vane via gears located in the rear of the housing. The gears are run in Toyota supercharger oil, Toyota part number 08885-80108. The lubricant costs about $50 for 50ml. Total gearhousing capacity is 130ml."