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Discussion Starter · #1 ·
Anybody done this on a 16V, I would expect that the cut-out would be tied to the WOT switch. I have owned several other vehicles that had this cut-out (5.0 mustangs). I would think that the way 4-5 HP feels in a 2200lb car it would be worth it.
 

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Re: Alternator cut-out switch (greatvw)

i've been thinking about this aswell.... haven't tried it yet, although it would be a super simple mod. i had a friend who used it in hes racecar, but only when he needed every last little bit of jam.
the one thing that concerns me would be how voltage dependant the cis-e motronic system is. i don't think short runs would be detremental, but i've tried to drive my car with less that 12v, and it blows at anything over 25% throttle. i'm guessing 'cause it can't fire the coil as effectively???
 

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Re: Alternator cut-out switch (Spinne16v)

quote:[HR][/HR]I cant imagine that it actually takes 4 or 5 horsepower to turn the alternator though. Even under heavy load. Correct me if I'm wrong..
[HR][/HR]​
IIRC, most 16v alternators are 90A.
when you have alot of electrical load, the magnetic field inside the alternator increases, and as each winding in the rotor flys by, there is a quantifiable resistance to that force.... sort of like nothing in life is free. then there's the constant added resistance of the brushes, bearings and friction of the belt...
next time i go to the dyno, i'll try it and see if it makes any measurable difference.
 

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Re: Alternator cut-out switch (Spinne16v)

Just going from the numbers a 90A alternator should draw at least 2 hp from the motor...that is just in electrical power and doesn't include any friction or windage losses. 3 or 4 hp doesn't sound completely out of the realm of possibility.
 

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Re: Alternator cut-out switch (MyGTI)

Ok , lets say that you have a 90A draw and the alternator is putting out 13.5 v . What kind of wattage is the alternator doing?? Whats the correlation between watts and horsepower?? Does the wattage output of the alternator directly refelct the hp drain on the motor? I'd be interested in figuring out just how much HP is lost. If you actually have enough load to draw 90 A i'm thinking that you might experience some of the negative effects desribed earlier.. So whats the formula for wattage?? P = I x E or was that something else..
 

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Re: Alternator cut-out switch (Spinne16v)

quote:[HR][/HR]So whats the formula for wattage?? P = I x E or was that something else..[HR][/HR]​
I think for amp, watts, and volts... it's Watts/Volts=Amps. But I can't remember how watts correspond with horsepower. I think watts over a period of time or something, maybe?
 

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Re: Alternator cut-out switch (greatvw)

1 watt = 1 joule/sec
745.9 watts equate to 1 horsepower, which is really a meaningless silly unit of measure from that island infamous for meaningless, silly units of measure.
It is imporant to note that both of these units are power, which is energy in a given time. Therefore if you want to know total energy, one must multiply by time. If one had a dyno run of their car, and hooked up a data logger to say the tachometer and the fuel draw, it would be possible to integrate this information over time and get out just how much energy it takes for your car to run the quater.
I for one might actually care about drag racing if there were a class that challenged people to achieve the most on the least amount of total energy.
Sorry about the above, what can I say? I'm a physics major.
 
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