My fan is hard wired so that it's on whenever the key is in the accesory postion or run postion. A buddy of mine told me that it's killing gas mileage and performance because it's not letting the engine get warm. My car will only get up to 150 degrees on the hottest of Florida days. So my question is, does it really make that much of a difference or is he misleading me. I was reading some of the articles trying to get information and I read that the fan is turned on at 222 degrees. So it sounds to me that what he is saying might be true. I also noticed that my passes at the strip get better and better everytime I run. So please help me out

 

at certain speeds (like on the freeway) the fan actually slows the incoming speed of air, hindering performance.

 

On my 305 tpi I have dual fans. the one turns on when the key is on on once the car runs both are on. However i am assuming that they speed up when the temp hits a certain point.

It is 27 F right now and my car warms up in about 5-8 min of driving and then stays at operating temp even when fans are continually running. it heats to about 200 then drops to about 175. then after a while back at about 200 and so on.

 

It can affect gas mileage and drivability. The car will continuosly run in open loop if the car never gets up to a certain temp. (I believe it's usually 160*). When the car's in open loop, it runs off of a predetermined program which makes the air/fuel ratio stay rich. During open loop, the computer does not recieve input from the oxygen sensor, therefore it can't alter the air/fuel ratio, thereby causing poor performance. Once certain parameters are met, the computer goes into closed loop, and then receives input from the oxygen sensor and begins to adjust the air/fuel ratio, idle, etc., accordingly.

If I were you, I would just drive your car with a scan tool, laptop with WinALDL, etc., and see how long it takes the computer to go into closed loop. If it takes 20 minutes, then I'd consider unwiring the fan. If it takes under 5 minutes, then you'll probably be OK. Also, don't forget that you will end up replacing fan motors more often, since the stock fans were not meant to run all the time. But, while your using a scan tool ,or other device, compare the temp. reading on the gauge and the temp. reading that the computer gets from the coolant temperature sensor (CTS). They can be quite different sometimes.