How Do I Prevent Low-Speed Overheating on a 500HP, GM LS3-Powered Datsun 240Z on 110-Degree Summer Days?
Q: Marlan, I have a 1971 Datsun 240Z with the LS3-based 6.2L, LS376/480 crate engine in it [current version GM PN 19370411; 495 hp at 6,200 rpm, 473 lb-ft at 5,000 rpm—Editor]. I live in Tucson, Arizona, where it regularly gets up to 105-110 degrees F in the summer. I have a really good aluminum radiator in it with a SPAL 11-inch dual fan-and-shroud puller assembly (SPAL PN 30102052) rated at 2,750 cfm. The radiator size is about 24-inches wide x 16-inches high, and I can’t go any larger due to the frontal dimensions of the car.
As long as I’m going at least 35 mph the engine temperature stays around 190 degrees (the thermostat is a 180-degree unit), which indicates to me that the radiator by itself is adequate. But when I have to stop or get in slow-moving traffic, the temp slowly starts to creep up. For that reason I’m very hesitant to take it out during the summer because I’m petrified about getting caught in a traffic jam and overheating. There just doesn’t seem to be any fan setup that offers any significant improvement in cfm flow that I can find for my size radiator.
I have a special air shroud which vents the air directly out through
