Those running alternator underdrive pulley
#26
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Originally posted by dDuB
thank you so much nz convertible for showing me the light, i understand now how i am so stupid and wrong all the time.. thank you for continually putting me down in my threads, i appreciate it
thank you so much nz convertible for showing me the light, i understand now how i am so stupid and wrong all the time.. thank you for continually putting me down in my threads, i appreciate it
Originally posted by 1987RX7guy
how exactly does slowing the alternator down hurt amperage?
how exactly does slowing the alternator down hurt amperage?
#27
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Originally posted by NZConvertible
Output current is logarithmically proportional to alternator revs; simple as that. The S4 alternator is rated at 70A, but the FSM test says that 55A @ 2500-3000rpm is normal. So you obviously need more revs to reach to 70A max output. Slowing the alternator down will obviously lower the output current.
Output current is logarithmically proportional to alternator revs; simple as that. The S4 alternator is rated at 70A, but the FSM test says that 55A @ 2500-3000rpm is normal. So you obviously need more revs to reach to 70A max output. Slowing the alternator down will obviously lower the output current.
Santiago
PS- I'm constructing an excel sheet with the RP pully I have going from idle and then from 800rpms all the way up to 8k rpms showing the UD rpms. I'll post that up in a sec.
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Originally posted by NZConvertible
Why is everyone here so damn sensitive? I have never put you down personally, I have only ever corrected what I believe to be incorrect information. There's a big difference. I can't even remember any other threads off hand, but in this one I was only trying to save you money. If I really wanted to put you down I'd just start calling you names. It'd require a lot less effort...
Why is everyone here so damn sensitive? I have never put you down personally, I have only ever corrected what I believe to be incorrect information. There's a big difference. I can't even remember any other threads off hand, but in this one I was only trying to save you money. If I really wanted to put you down I'd just start calling you names. It'd require a lot less effort...
Originally posted by NZConvertible
Output current is logarithmically proportional to alternator revs; simple as that. The S4 alternator is rated at 70A, but the FSM test says that 55A @ 2500-3000rpm is normal. So you obviously need more revs to reach to 70A max output. Slowing the alternator down will obviously lower the output current.
Output current is logarithmically proportional to alternator revs; simple as that. The S4 alternator is rated at 70A, but the FSM test says that 55A @ 2500-3000rpm is normal. So you obviously need more revs to reach to 70A max output. Slowing the alternator down will obviously lower the output current.
now my next point... the whole reason behind underdriving the FD alt was not to correct the fact that my volts might be too high... since i have the fd alt already and no big stereo, i figured underdriving it would give me that tiny bit of extra HP while still being at stock level of alt power... now the way i was looking at this whole thing was that underdriving an alternator gives you a lil more power. I would never do the main pulley on a street car cuz i think thats dumb, but since i already have a more powerful alt that i really dont need the extra power of (its just nice sometimes at night with the lights, wipers, and heat on) then underdriving it would essentially give me the power without reducing my making my power output too low
#31
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Originally posted by 1987RX7guy
So the regulator only affects voltage output?
So the regulator only affects voltage output?
I'm constructing an excel sheet with the RP pully I have going from idle and then from 800rpms all the way up to 8k rpms showing the UD rpms.
Originally posted by dDuB
the other thread where i felt attacked was my weight reduction thread where you said how worthless removing some things were, or something along the lines of "let us know what happens when you have a flat and are stranded on the side of the road" when you said how stupid taking my spare tire out, even though i had already explained i have AAA... my point was that it seems like you attack ppl a lot for their ideas or things they want to do
the other thread where i felt attacked was my weight reduction thread where you said how worthless removing some things were, or something along the lines of "let us know what happens when you have a flat and are stranded on the side of the road" when you said how stupid taking my spare tire out, even though i had already explained i have AAA... my point was that it seems like you attack ppl a lot for their ideas or things they want to do
i figured underdriving it would give me that tiny bit of extra HP while still being at stock level of alt power... now the way i was looking at this whole thing was that underdriving an alternator gives you a lil more power
Higher output alternators require more engine power to turn them. This is an unavoidable fact of life (the one where you get nothing for free). The FD alternator has an output 43% higher than the S4 one, and as a result it'll suck approximately that much more power from the engine. If you underdrive the alternator, you'll reduce both that power draw and the output by the underdrive percentage.
But if you do the maths, the power gain from underdriving a 100A alternator by 20% is ~0.5hp. You'll have trouble measuring the power gain at the wheels, let alone actually feeling it. Did you notice the tiny power loss from installing the FD alternator? No, because it was very small. The gain from underdriving it will be even smaller...
If the underdrive pulley is a 20% one, your FD alternator will end up about the same an 80A S5 one, and draw a tiny fraction of a hp more power from the engine than the stock S4 one. The numbers are so small IMO it's just not wasting time and money chasing them. Be happy with your new alternator's healthy capacity and spend the money on something you'll actually notice. And get that voltage regulator checked.
Originally posted by neptuneRX
I'm getting 15.5 off my honda accord with everything off
I'm getting 15.5 off my honda accord with everything off
#33
Eat Rice Don't Drive it.
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Originally posted by NZConvertible
That's why it's called a voltage regulator.
It's nice, but what does it prove?
That's why it's called a voltage regulator.
It's nice, but what does it prove?
Santiago
PS- the graph was also for my own use as I have that particular pully.
#34
I have an underdrive crank pulley, and an overdrive alternator pulley. These are not aftermarket pulleys, but pulleys off of cars at the junkyard. Charging system is fine, cooling system is fine. I believe they added alittle power, but no butt dyno proof, but its too little to tell even if it did.
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FD Alt is all good
After talking to silverrotor i just wanted to let everyone know that my alt is FINE. The intention of this thread was not that there was a voltage problem, it was for pure HP gain (ie the underdrive pulley). I have had no problems with the alternator or my powering system, it just came up in this thread for no reason. Everything is fine with it, no worries to anyone thinking of getting one from silverrotor its a great product and hes a great guy
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ugh....... you dont even know if im above 14.7.. The stock volt gauge (at most) will sit close to half way inbetween the 14 and 16v marks, so *around* 15, but the stock gauge isnt very accurate. Mind you that is the MOST it will ever read, it is usually about a quarter past the 14 mark. As silverrotor stated to me "If the Voltage Regulator was the culprit, 2 things would either happen. You'd either get very low output from It resulting In a very noticable rough Idle leading to a flat battery or with the other option, you'd get an unlimited amount of ampherage resulting In a popped Main Fuse." I have neither a rough idle or am i popping fuses, and ive been running this for a few months now
#39
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Originally posted by NZConvertible
The FSM disagrees with silverrotor. Anything over 14.7V is not fine. Just letting you know...
The FSM disagrees with silverrotor. Anything over 14.7V is not fine. Just letting you know...
Besides, did you not read and comprehend that he has not made a DMM check?! *Geez*
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Originally posted by dDuB
ugh....... you dont even know if im above 14.7..
ugh....... you dont even know if im above 14.7..
Originally posted by dDuB
...im always running at higher than 15volts because of the FD alt which ive been told is too high for some of the stock electrical components...
...im always running at higher than 15volts because of the FD alt which ive been told is too high for some of the stock electrical components...
#41
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Originally posted by silverrotor
I'm saying that If their was a problem that existed, I would have had 100's of PM's to suggest that the FD Alternator should not be an upgrade to a FC.
I'm saying that If their was a problem that existed, I would have had 100's of PM's to suggest that the FD Alternator should not be an upgrade to a FC.
Besides, did you not read and comprehend that he has not made a DMM check?!
#42
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What the basis of this thread was to Implement an Underdrive Pulley and than eventually spilled over to the potential exceeding of 14.7v with his Alternator. As dDuB said way back was he was relying on the stock Voltage Guage. Right? Atleast give the scenario that. So why would you be persistant to dwell on readings that are being read off the stock Guage which were not only extracted from the stock Guage but were mentioned very early In the thread?
In a way, I'm Interested to know If the Voltage Regulator was fried as a byproduct of miswiring It Incorrectly at one point. In any case, both dDuB and I will deal with this accordingly. I'm a pretty fair guy. Anyway, nothing can be said further until a reading via a DMM Is done.
In a way, I'm Interested to know If the Voltage Regulator was fried as a byproduct of miswiring It Incorrectly at one point. In any case, both dDuB and I will deal with this accordingly. I'm a pretty fair guy. Anyway, nothing can be said further until a reading via a DMM Is done.
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