Just did some datalogging on a trick that I thought up to bring down the ECT (Engine Coolant Temp) while waiting in the staging line, burn-out box, and up to the point of staging itself. If you find are worried or need to keep the coolant temp down, as in the case of autos, this will help out.

This is the data that I found from testing on a normal run around town with a little spirited driving. The Engine Fan#1 relay is activated by a water temp sensor set for about 203°F. My fan came on at 203°F and spiked to 204°F before shutting off at 199°F. It actually continued to drop further to 196°F before leveling off due to the slow nature of the '05 Scion OBDII protocol.

Note: '07-up with the CAN protocol should render data much faster.

My IAT temp hovered around 131°F under my vented hood with intake NACA Duct. OAT (Outside Air Temp) was an extremely humid 84°F. When the Engine Fan #1 came on, the IAT would spike to 136°F.

When the A/C system is activated, Engine Fan #1 and #2 are energized and left on most of the time while the car is stationary or driving slow. Having the fans running continously while remaining stationary does a far better job of lowering ECT than from the automatic temp trigger. In this mode, my temp quickly went from 203°F (waited till normal trigger temp) down to 178°F before taperring off at 174°F. It was abe to maintain this temp for several minutes.

It did come with a price, though, as IAT spiked to 141°F. This ws caused by the increase of hot airflow eminating from the radiator and getting trapped under the hood. My car has a vented hood so expect a sharper rise with a non-vented hood. Turning off the A/C system turned off the fans. The IAT made a marked descent to the normal 131°F while the ECT slowly climbed.

Note: This is mostly relevant to SRI due to the filter being in the engine bay. A CAI, with it's filter outside of the engine bay would only suffer higher temps due to heatsoak of the intake tubing and the MAF sensor housing. These can be shrouded to defelect radiated heat.

Now what to do with this data and how to apply it. We can see that IAT can change more rapidly than the ECT. We can also see that ECM tries to maintain the ECT just under 200F via the temp triggered system. Running the A/C allows for both Engine Coolant Fans to operate continuously which does have a trade-off by a slight increase in IAT.

When you get to the staging lanes, turn-on your A/C with the dash blower on it's lowest setting. This will be enough to activate the fans without risking adding to much heat into the oncoming airflow to the radiator by the A/C condensor. If possible, you could raise your hood to mitigate the excess heat build-up in the engine bay with the resulting IAT increase. Proceed to the burn-out box with the A/C on. Don't worry about power loss as the ECM will cut the clutch on the compressor during heavy engine loads as when you do your burn-out. Once your complete your rollout from the burn-out box, you can then tun off your A/C. This will begin to lower the underhood and IAT temps. The ECT will increase but at a much slower rate. If you have a vented hood or CAI, you can leave the A/C engaged till you are staged in the lights.

The purpose of this procedure is not to give bette ET's. It is just one method to keep your car from overheating which will lower power level and cause possible engine damage if extreme. There are many other methods to lower ECT. This is just one that is extremely easy to do and free.