| If you have the necessary tooling. I made two, one with a TL494 PWM generator and one with an 08M2 microcontroller. For one circuit, everything was about $40 (including extra's just in case) The TL494 chip wasn't as easily adjustable as was the microcontroller (through programming), and the microcontroller circuit was far more simple. So I ended up going with that design instead. I used the output of either to pulse a LDO regulator, and used the regulator output to activate a FET array, since the microchip output isn't high enough to activate a large FET. I also had a secondary sensor inside the circuits to control a 1" cooling fan for the MOSFET heatsink. I grounded the condenser fan relays and used that as my power source. It was another one of those things I thought about making a few of and seeing if anyone wanted to cover parts for them... But I made 3 and used them on all my cars instead :) Another thing, with the 08M2 I had extra inputs/outputs so I used a second sensor/output to control an electric water pump speed based on temp. For that car (pro street car) the water pump is off until the car gets to 140 (in-block temp sensor) then it ramps up from 0-100% depending on the temp between 140 and 160 (thermostat setting). The fan is driven by the radiator outlet temp, and is set from 0-100% depending on where the outlet temp is between 120 and 140. The reason I drive them off the radiator outlet is: I don't want the fan to be on if the air moving through the rad is enough to cool the coolant down, increasing efficiency.
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1992 300ZX NA 5 Sp (Dead)
1990 300ZX NA Auto 2+2 (Dead)
1990 300ZX TT 5 Sp (Building)
2004 G35 Sport 6MT (DD) |
