alternator output during high loads

[rickjones]

I have been noticing that on some fuel injected vehicles the voltage drops to battery voltage 12.x-12.6 volts during wot operation. Does the pcm stop fielding the regulator during wot? Maybe you know something I don't?

 

[waross]

That would give you one or two HP extra.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Harry6888]

You're correct. Some computer controlled cars also turn off the airconditioning during wide open throttle.

 

[marcusaurailius]

Rick, it shold not matter if the volts drop,

cos the computer has got some ..built in.. compensation tables.

and on the one i got, compensates down to 7 volts !!,

the lower the voltage, then the longer it takes the ..injectors.. to open.

so when the volts are low, the computer will open the injectors earlier, to compensate

on the one i use , you can have a ..defult .. setting,

or a programmed setting, according to the injectors workings/duty cycle

and will also alter the ignition as well

hope this gives you some info

regards Marcus

 

[rickjones]

I am familiar with injector dead time compensation. Do you know if its normal for PCM to stop controlling the alternator and solely depend on battery voltage during high loads, is this a generic method on all FI systems or does it depend on manufacturer?