RE: Electric fan wiring
Big difference. The fan is typically only on 1/2 speed with the AC on. And with the AC off(at the track), the fan does not come on until some ridiculous temperature, like 215*. Heat soak is rampant at those conditions and any repetitive runs will show it dramatically.
The mod basically bypasses the VCRM control feeding direct battery voltage to the fan to run at 100% for quick cool down times after a run down the track. Switch the relay off and the fan control is handed back to the VCRM just like stock for normal driving.
Consistency is where it proves itself. Originally, I would switch it on when approaching the burnout box and leave it on through the return trip to the staging lanes, pop the hood and leave the fan run until I felt the air from the fan was cool or until the temp gauge was at the bottom of 'normal'.
Later I added a digital programmable controller to the bypass circuit. This eliminated the manual switching off/on of the fan bypass. Now I switch the bypass on and the digital controller takes care of the rest automatically. With a 160* T-stat, I have the controller programmed to turn on at 180* and off at 165*. At the end of the day at the track, I switch control back to the VCRM.
One caveat... the 40A cube relay has been replaced once and evidently the extra service took a toll on my stock fan motor. If you remember back at SSHS my fan wasn't working reliably. I have since replaced the motor(easy job) and I hope to rig up an industrial strength relay to replace the cube type.