wesam

One of my friend used to do a constant 10.9 quarter mile runs
ones he tried to make his fans working at full speed before the run using hp tuner his time dropped to 11.3 in the same day same weather
any body tried this before ?
we didn't expect this drop in performance due to amperage drop caused by fans

02*C5

iTrader: (1)

You have to remember that while the fans are not being belt driven, they are assisted by the alternator and your adding more load when you are almost are full load in a 1/4 mile run.

wesam

i know that but i can't imagine that the load coming from the alternator will drop the time by 0.5 sec !!!

JeaneZ28

iTrader: (3)

did you only do one run with fans on high?

snake charmer

iTrader: (118)

i use a slp fan switch . usually just run the fans on high in between runs to try and keep things cool . this is an interesting read though .
wonder what times you could run with them off doing a pass ?

wesam

he tried twice and had the same drop in time

wesam

?????

Old Geezer

iTrader: (3)

Do the math...
If the alt is full fielded, and putting out 140A, @ 13.5 volts, the wattage is 1890.[volts x amps= watts] Converting that to HP= [1890x.001341]=2.53 HP. And, that 2.53 is not the added HP loss, as there's already a load of some amt on the system.
That's not likely to be the cause of the loss in performance.
Other causes:
Lower volts to the ign.?
Low volts to the fuel pump.?
PCM incapable of sufficient inj voltage correction?

01ssreda4

iTrader: (96)

While true a loaded alt does pull on an engine, listen as you hook up a jump start on a dead battery, in this case it seems logical its probably an overall voltage issue as geezer stated. Electronics run better and more efficiently with more voltage.

jimmyblue

iTrader: (11)

Full time fans will push the ECT down, maybe he runs
better (tune, or simple motor efficiency) when hotter.

veee8

iTrader: (40)

If the fans were running full tilt at wot down the track, they become a major restriction, it is like hitting a brick wall of air. That is why there is hysteresis in the software to shut the fans down at a certain mph, they would become more of a hinderence then help at speed.

SOMbitch

iTrader: (8)

They are supposed to cut off at 35mph anyway so.......