Marcus
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| posted on 22/3/09 at 08:19 PM |
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Last ounce of power
This is hypothetical really, but I'd be interested to know if it would work.
On a track day / race where every bhp is at a premium, would it be worthwhile disabling the alternator using an Air Con solenoid on the pulley so that
only the pulley spins with a switch to kick in the alternator itself when needed.
Marcus
Because kits are for girls!!
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Howlor
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| posted on 22/3/09 at 08:21 PM |
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Yep my BMW does that. It kicks in when you brake.
Steve
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Paul TigerB6
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| posted on 22/3/09 at 08:22 PM |
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I wouldnt say power is at a premium on a track day........... and race regulations will likely require an alternator in which case its fitted, or not
in which case it wont be!!
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zilspeed
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| posted on 22/3/09 at 08:41 PM |
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I cerainly know people who run without alternators in race situations.
Save a little power and saves a little weight.
Not so sure it's worth the grief of arranging a bypass system if you're still carrying the alternator around everywhere.
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ReMan
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| posted on 22/3/09 at 09:19 PM |
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A few more pounds of skil will be of more benefit, allegedly 
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Marcus
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| posted on 22/3/09 at 09:42 PM |
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quote:
Yep my BMW does that. It kicks in when you brake.
Bugger, the amount of things I've invented over the years....10 years after someone else is amazing 
Sat Nav, car stereos with USB ports on, in-car pcs and many more......all mine I tell you!!!!
Marcus
Because kits are for girls!!
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02GF74
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| posted on 22/3/09 at 10:10 PM |
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quote:
Originally posted by Howlor
Yep my BMW does that. It kicks in when you brake.
Steve
that's damn clever - increase engine load to help engine braking.
Does it use a relay operated by brake pedal to connect alternator electricazlly or is there some mechanics to coneect the alternator drive?
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tootall
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| posted on 22/3/09 at 11:28 PM |
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its controled by the ecu as it turns on and off as battery charge rises and falls and when brakes are applyed its only a symple switch usualy a
elecromagntic clutch built into alternator or air con pully so it free wheels
some people dream of sucsess, others just get on and do it !!
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mcerd1
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| posted on 23/3/09 at 10:03 AM |
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(I'm not that good with this stuff)
but can't you just disconnect the altenator eletricaly to reduce the load ?
(an isolator switch / relay wired up to what ever you like ?)
it might not be as good as the clutch in the pulley, but its allot cheaper and probably lighter
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BenB
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| posted on 23/3/09 at 10:59 AM |
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There are some reports that suggest that running an alternator unplugged can cause all kinds of mischieve inside the regulator because all the lovely
juice being made isn't going anywhere. It's true it'll take less power to turn it over than if you had it connected but might cause
problems in other ways...
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mcerd1
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| posted on 23/3/09 at 11:29 AM |
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quote:
Originally posted by BenB
but might cause problems in other ways...
in that case I guess you'd need to wire in the cut-out inside the altenator - before the regulator if thats possible :?
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trikerneil
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| posted on 23/3/09 at 11:36 AM |
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If you fitted a switch into the field coil then the alternator wouldn't generate any power, this would reduce the load on the engine
I use this system on a home made generator I built so that startng the engine is easier. As soon as the engine is running at speed I switch the field
coils back on and charging begins.
I only use this for a few seconds at each startup, I don't know if there are any long-term implications.
HTH
Neil
ACE Cafe - Just say No.
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02GF74
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| posted on 23/3/09 at 02:15 PM |
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^^^^ was gonna post about this; disconnecting alternator, as I said in my origianl response - well it was late on Sunday - is not too clever for
reasins mentions.
I thorght some more about it and disconnecting the filed current - i.e. the charge lamp would be a better and safeer solution.
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procomp
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| posted on 24/3/09 at 08:16 AM |
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Hi
LOL this is a subject that comes up around every race paddock.
If the race regs say you have to have a fully working alternator then it's really quite simple. Make sure the battery is fully charged before
starting the race. The alternator is not then working it's nuts off trying to charge the battery. However if the Regs say the alternator is
optional ( Ie classic formula ford ) then dont fit one at all.
It's why you see lots of racers having there cars push started in the collecting area.
Cheers Matt
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