Alternator WOT cut-off switch...
04-19-2005, 02:56 PM
#1
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Alternator WOT cut-off switch... How much can I gain from this? Is it worth it? Will I hurt anything. The idea is to cut off the alternator so it does not charge at WOT to save some hp.
Any thoughts? I saw one on e-bay and thought it would be a good idea to make my own. But if the alternator does not eat that much then I will scrap the idea.
Any thoughts? I saw one on e-bay and thought it would be a good idea to make my own. But if the alternator does not eat that much then I will scrap the idea.
04-19-2005, 04:12 PM
#5
I dont think you would want to hold it at WOT very long and i think it would shorten the life of your alternator having to always make up that charge you lost while at WOT. Thats what i think..someone correct me if im wrong.
04-19-2005, 04:28 PM
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I wouldnt run it on a DD, but if its a weekend mainly track use car then just hook a trickle charger up to it and it shouldnt be a big deal. But I cant see you getting to much hp power from it.
04-19-2005, 05:23 PM
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Well the battery will not drain much for a short WOT run. How long are you at WOT? If at the track only a few seconds at a time. Not enough to drain the battery. Especially if you are not running anything else.
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04-19-2005, 10:36 PM
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I believe you would want the full charge of the alternator at WOT. Would it not be better for items like ignition coils, fuel pump, injectors, etc. to see 14V versus the 12V with the alternator cutoff?
Last edited by felton316; 04-19-2005 at 10:41 PM.
04-20-2005, 12:10 PM
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I have a UDP. SO I guess I will leave it. Every little thing counts. Coils will give more spark at 14.4 and fuel pump will push harder too.
04-20-2005, 12:16 PM
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How would it save though, the alternator is still spinning? And isnt it doing the same amount of work whether its pumping power or not? Just interested, never thought about it.
04-20-2005, 09:41 PM
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It takes more force to turn it when its working due to the magnetic load, but it still needs to use power to turn it when its not charging. Also when the battery is fully charged and low accesssory, ie. no a/c, headlights and whatnot, the alt isnt fully charging anyways. I also would want to know I have full voltage presnt for proper spark when running WOT.
04-20-2005, 10:01 PM
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Originally Posted by The old man
It takes the same amount of power to spin it charging or not. 
Is not like an A/C compressor that has a clutch that ingages and knocks some power off.
Is not like an A/C compressor that has a clutch that ingages and knocks some power off.
04-20-2005, 11:16 PM
#16
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Originally Posted by The old man
It takes the same amount of power to spin it charging or not. Is not like an A/C compressor that has a clutch that ingages and knocks some power off.
Is not like an A/C compressor that has a clutch that ingages and knocks some power off.746 watts = 1hp
746 watts/14.4 volts = 51.8 amps.
So, when the alternator is producing 52 amps, it is using 1hp to create the electricity by itself, not to mention driving the belt and the friction encountered by the bearings.
I still say that 14.4 volts to the coils and fuel pump is a lot better than 12.6(fully charged battery).
04-21-2005, 08:48 AM
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Originally Posted by Fandango
Are you sure about that?
746 watts = 1hp
746 watts/14.4 volts = 51.8 amps.
So, when the alternator is producing 52 amps, it is using 1hp to create the electricity by itself, not to mention driving the belt and the friction encountered by the bearings.
I still say that 14.4 volts to the coils and fuel pump is a lot better than 12.6(fully charged battery).
746 watts = 1hp
746 watts/14.4 volts = 51.8 amps.
So, when the alternator is producing 52 amps, it is using 1hp to create the electricity by itself, not to mention driving the belt and the friction encountered by the bearings.
I still say that 14.4 volts to the coils and fuel pump is a lot better than 12.6(fully charged battery).
This is assuming 100% efficiency. Also the power to turn the alternator at that rate is pretty good too due to the inertia of the armature. But it seems like it is not worth while considering when you are WOT you are not running anything anyhow so there is not much power taken by it.
