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Location:
Adelaide
Registered:
November 2003
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Alternator "override"
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Tue, 10 February 2004 22:45
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After plenty of talk about the benefits of an electric water pump on a diff thread, i kinda came up with the idea (although i'm sure its not new) of a "switchable" alternator.
Basically just have a button at the very bottom of the accelerators travel. When depressed is breaks the circuit return from the alternator and therefore it won't put any load onto the engine as it won't produce a magnetic force inside itself. There would also have to be a voltmeter that if the battery lowered below say 12.5 volts or soemthing, would automatically re-join the circuit.
I haven't really thought this out completley, just for about 10 mins, so what does everyone think? Stoopid idea, or has some promise? With this and the elec water pump, your bound to free up some decent power at least under full accel...
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Location:
Terrigal
Registered:
May 2002
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Re: Alternator "override"
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Tue, 10 February 2004 22:57
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Not much help I realise, but it's not the first time i've heard of that idea. I think a magazine did a tech write up on a simple circuit to do just that.
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Location:
Montrose, VIC
Registered:
May 2002
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Re: Alternator "override"
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Wed, 11 February 2004 01:17
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Buy a Motec and it's one of the options for the programmable outputs 
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Location:
Sydney
Registered:
January 2003
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Re: Alternator "override"
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Wed, 11 February 2004 04:59
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by just doing some quick maths i'm thinking that it would not really be worth the hassle,
if you are pulling say 50 amps then thats 600 watts, assuming that an alternator is ~50% efficient then you are loosing about 1.2kW, not counting pulley losses because they will still be there if you freewheel it.
if you have a motec or something that it is easier to do on then it would probably be worth doing.....
just my 2c
Richard
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Alternator "override"
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Wed, 11 February 2004 06:09
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yup. MAXIMUM benefit is not much
even if you had a 100A alt = 2.4kw, remember that the alt only provides the current being used...
so if you had EVERY electrical thing on in your car (headlights, fans, stereo, brake lights included) then the most you could hope for is maybe 2kw.....
this is tiny compared to mechanical pumps..
for zample:
supercharger on top fueler = 100-200hp or so,
clutchless engine driven fan at high rpm maybe 5-15hp.
oil pump, wuite a bit.... dry sump pumps take a fair few hp to drive...
water pump, less than oil pump, but still significant...
anyhoo, there are "kits" available for what you want to do.. basically a switch under acc pedal to turn off the sense power to alt under WOT.
Cya, Stewart
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Location:
Montrose, VIC
Registered:
May 2002
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Re: Alternator "override"
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Wed, 11 February 2004 12:22
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I didn't say you HAD to muy a Motec to do it, just that I noticed it as one of the output options, as a way of saying it was already common practice in motorsport
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