Issue: 99% of the time, The Shuttle's cooling system works great, with the TRD 160F thermostat keep engine temps in the 170-175F range.  However, infrequent occasions cause engine temps rise to 190F.  Now, 190F itself is no cause for alarm.  But, this does indicate to me some weakness in the cooling system.  And, actually, it's not a weakness in the cooling system, but rather an issue I've created by placing additional coolers in front of the radiator.  As such, it appears the large FMIC and various oil, trans, and power steering coolers block just enough air flow to the radiator to cause engine temps to rise to about 190F during spirited low-speed driving - say, when I'm getting on it, 0-60 stoplight to stoplight, and quickly slowing to 20-30 mph.  Below about 35 mph, insufficient forward velocity prevents sufficient air flow through the FMIC, the various coolers, the a/c condenser, and finally to the radiator.  So, I'm adding a pair of 12" pusher fans to the front of the a/c condenser and perhaps implement a thermostatically-controlled radiator spray-bar.  The way I see it, if water spray-bars are good enough for the IC on a factory EVO, it should work wonders for a radiator.

Prior to implementing the above new fans and sprayer, I performance the following...

• performed some experiments with water spray that lead me to believe that it will drastically affect radiator efficiency in the same way it increases the efficiency of the EVO intercooler. Four gardening sprayers hooked to the rear window washer pump yielded a large yet fine mist in front of the radiator such that I was able to lower engine temps from 190F back to 175F after about 20 seconds of spraying.  Coupled to the radiator fan control and placed on a timer or thermostatically-controlled switch, I can see using this to cool the car anytime.. like between runs at the track.
• acquired an ST205 spraybar, an ST185RC windshield washer bottle, and a windshield washer pump from a Supra which fits the ST185RC's washer bottle as the third pump for the IC sprayer.  First of all, the ST205 spraybar flows about like the Mississippi River.. water water everywhere and not necessarily in a fine spray.  Come on Toyota.. what were you thinking??  Thankfully, the Supra pump fits the RC water bottle, and together, they fit just perfectly in place of the stock water bottle.  I simply need to wire-up this third pump to a switch, either temperature activated or a manual push-button in the driver cockpit.