Found high out put alternator $288
Voltage drops are an alternator issue, not battery. The battery only exists to start the car. If the battery is failing and not storing power, you'll know it by having issues starting the car.
Evolving Member
Joined: Dec 2005
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From: Rochester ny
well i asked for an optima battery for my b day coming up. after 4 years i think its enough on the stock battery. we shall see i suppose?
I was thinking about this some more.
it takes power to make power... I think the equation is that for every 25 amps the alternator outputs, it costs 1 horsepower. the under drive pulley reduces the output by 20% which should give you around 1hp back (only counting the alternator). if you put a 180amp alternator in and under drive it by 20% then you'd be down to 144 amp output which is still a good bit over stock.
hence why under drive pulleys are only really used by extreme drag cars and ricers (what's 1hp on the street?).
it takes power to make power... I think the equation is that for every 25 amps the alternator outputs, it costs 1 horsepower. the under drive pulley reduces the output by 20% which should give you around 1hp back (only counting the alternator). if you put a 180amp alternator in and under drive it by 20% then you'd be down to 144 amp output which is still a good bit over stock.
hence why under drive pulleys are only really used by extreme drag cars and ricers (what's 1hp on the street?).
Thread Starter
Evolving Member
Joined: Apr 2008
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From: Buffalo NY
You guys are thinking too hard, Im doing this to stop my headlights from blinking. Im pretty sure that this alternator has the same stock dimensions, and the good thing about an underdrive pulley is the reduced inertia and quicker revs.
the fact that it's an under drive pulley means it's "under-driving" the alternator and other accessories because it's smaller. stop and think about what that means for a moment.
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iTrader: (3)
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From: Lakenheath UK, but my heart is in PR
I was thinking about this some more.
it takes power to make power... I think the equation is that for every 25 amps the alternator outputs, it costs 1 horsepower. the under drive pulley reduces the output by 20% which should give you around 1hp back (only counting the alternator). if you put a 180amp alternator in and under drive it by 20% then you'd be down to 144 amp output which is still a good bit over stock.
hence why under drive pulleys are only really used by extreme drag cars and ricers (what's 1hp on the street?).
it takes power to make power... I think the equation is that for every 25 amps the alternator outputs, it costs 1 horsepower. the under drive pulley reduces the output by 20% which should give you around 1hp back (only counting the alternator). if you put a 180amp alternator in and under drive it by 20% then you'd be down to 144 amp output which is still a good bit over stock.
hence why under drive pulleys are only really used by extreme drag cars and ricers (what's 1hp on the street?).
and you want scientific testing: http://www.teamscr.com/pulleys.htm it's amazing the the only people who get big gains are the ones selling parts or chumps who purchased them.
The Horsepower Story
With various aftermarket manufacturers claiming up to 15 horsepower gains with their underdrive pulleys, we set out to the dyno to find out how much power WE could expect on our 1999 ITA-prepped Saturn twin-cam powerplant. The results might surprise you, but here they are.
Because there were no pulleys available at the time, we went to the extreme and actually REMOVED the accessory drive belt (only for one run, of course) to see what the impact would be to ZERO drag due to the accessory drive – sort of pulleys with infinitely small diameters. We figured that if we saw a big gain without a belt, that the pulley gains would be somewhere inbetween, right?
We fired up the dyno and low and behold, removing the belt netted a whopping 3 HP (and we’re rounding UP). That's it. The number was repeatable, and even correlated to data run earlier on the doomed BMW motors - they saw similar results in their application.
So, in light of the fact that 3 HP was completely without a belt, we estimated that the best we could do was to underdrive a few components by 20% - or a theoretical 0.6 HP gain (3 HP x 0.2). After that, it hardly seemed worth it to try to custom fabricate pulleys for less than a 1 HP gain.
With various aftermarket manufacturers claiming up to 15 horsepower gains with their underdrive pulleys, we set out to the dyno to find out how much power WE could expect on our 1999 ITA-prepped Saturn twin-cam powerplant. The results might surprise you, but here they are.
Because there were no pulleys available at the time, we went to the extreme and actually REMOVED the accessory drive belt (only for one run, of course) to see what the impact would be to ZERO drag due to the accessory drive – sort of pulleys with infinitely small diameters. We figured that if we saw a big gain without a belt, that the pulley gains would be somewhere inbetween, right?
We fired up the dyno and low and behold, removing the belt netted a whopping 3 HP (and we’re rounding UP). That's it. The number was repeatable, and even correlated to data run earlier on the doomed BMW motors - they saw similar results in their application.
So, in light of the fact that 3 HP was completely without a belt, we estimated that the best we could do was to underdrive a few components by 20% - or a theoretical 0.6 HP gain (3 HP x 0.2). After that, it hardly seemed worth it to try to custom fabricate pulleys for less than a 1 HP gain.
Last edited by theblue; May 22, 2008 at 11:36 AM.
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Joined: Nov 2006
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From: Austin, TX
If it does create more resistance, as long as it is smaller than the amount that the stock pulley had, you're still seeing a decrease in overall "resistance" (I'm using the term loosely, the real word would be moment of inertia) in the system, Which means that the engine is still going to rev up faster than stock, but of course all of this is not considering how much hp is gained.
You're never making any extra power, but simply making the whole "accessory drive system" more efficient. Which is where lighter, smaller parts free up the power, but if you put on a part into the system which is less efficient, in terms of amps created per hp from crank used, then you're simply canceling yourself out.
Personally I've learned to live with the lights dimming slightly when I'm idling
