Drag Racing with manual fan switch....

[Guardiannknight]

I was wondering. Would it be wise to keep the fan on high, low, or just stock when going down the drag strip? Leaving the fan on would keep my car at the best temp(I have 160 thermy)for HP. But, would it hurt the performance due to the fan pulling some power? I was wondering what everyone else does, for those that have the manual fan switch. Reason I'm asking is, I'll be going to the drag strip this up coming Thur. and just have installed the manual fan switch. Thanks for any replies. [img]smile.gif[/img]

[NBMA4V6]

our fans are electric...so it does not pull power from the motor...

however when i race i run with them on low [img]tongue.gif[/img]


Good Luck

[Guardiannknight]

Thanks for the reply, I knew that the fans don't pull power from the motor, but they do however pull from the alternator. Sorry, I should have been more clearer in the first statement. It was getting late. ;) I was wondering if the fans would pull enough to hurt performance from the spark plugs. I always make sure I turn my stereo system off before dragging. I was wondering if the fans would make any difference also. I may run mine on low also, since you seem to be doing just fine from looking at your times NBMA4V6. ;) Thanks again for any replies.

[MidLifeSpeed]

I use the fans in the staging lanes, and turn them off when staged and ready to go.

Try turning the fans on at highway speeds, for example ... you will certainly feel the extra turbulence under the hood as the fans fight the ram air effect over the radiator.

I don't know if this will make a difference in a 1/4 run, but I usually turn mine off "just in case".

Additionally, leaving them on (manually) when the car is traveling over 45 mph will set a "fan relay circuit" DTC code.

[Only4U]

<blockquote>quote:</font><hr> Additionally, leaving them on (manually) when the car is traveling over 45 mph will set a "fan relay circuit" DTC code.<hr></blockquote>

correct me if i'm wrong here...but i think there is a way to bypass this dtc code. depending on rpm's, your pcm turns the fan off anywhere between 40-50 mph and then back on when you go below 40 mph. well, my ses light pops on when i turn the fan on before 40mph (this is the first time i reach 40 mph when i first turn my car on)--but it doesn't come on till AFTER the fan is supposed to shut off (over 50mph) because the computer is realizing that the fan is on when it's supposed to be off. so, what i tried was this: (this will probably only work if you have led lights to indicate when the pcm turns the fans on/off--the $75 switch from slp has no lights...i custom did my switch so that i have lights to tell me when high/low speed is on whether the pcm does it or whether i do it) but watch the light and when you reach about 50 mph it will go off, then decelerate until the light comes back on (indicating that the pcm has turned the fan back on). after this happens, you can turn the fan on yourself and you won't have to worry about an ses light UNTIL you turn your car off and have to restart it. when you restart your car, you have to follow this whole procedure again to avoid the ses light. of course, if you get the ses light, pull your car over, turn it off, unplug the ground to the switch (i don't know what you do with the slp switch but i have a switch that turns my custom fan switch ground on/off when i want to turn it on/off) then turn your car back on and wait a sec. then turn the ground switch on while the car is running. turn the car off, turn the switch off, wait 2+ minutes and then start everything back up again AND FINALLY turn the ground switch back to it's ON position. you should have no ses light then. this works for me, it may be TOTALLY wrong and not work for ANYONE else, but i haven't gotten an ses light since i started trying this. give it a shot, if it doesn't work, holla back.

[NBMA4V6]

another reason to buy the SLP fan switch...dont have to worry about codes..ive had the switch from them for a year..not a problem..and NO CODES

Jeff W

[Only4U]

ya, but to save $60, i'd much rather get an ses every now and then--it's easily fixable and i know that there is nothing wrong with the engine.

[navyblue2000]

the way to re route the problem...of course if you wanna go high, you can only use 1 fan on high, but you can still get two on low...instead of grounding one wire, put it under the adjacent lead on the relay. you'll never set a code, because you're OVERRIDING the computer, not telling the computer to turn on early, causing a windows 98 "what, why's this happening?" *poof* SES
:D

[Guardiannknight]

Hey, thanks for all the replies. You all have been a great help. ;)