USMC_Turbo6
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How powerful of an alternator can we run on our cars?
Alternator
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I run this one. You can set the voltage to whatever you want between 12-18 volts. My car never falls below 14.2 volts with headlights, a/c, everything on. It makes the power windows nice and fast too. Rollerized bearings so very quiet. 2 years, 20k miles, and no issues.
GM
86 - 87 Grand National 3.8L Turbo
37864 - Chrome 200 Amp
47864 - Natural 200 Amp
GM
86 - 87 Grand National 3.8L Turbo
37864 - Chrome 200 Amp
47864 - Natural 200 Amp
USMC_Turbo6
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where did you get the 240 from? That's what i would like to have in my car! Do you remeber the price?"
there is no limit to how big an alternator you can put on the car---------but the car will only consume the amperage that is determined by the electrical load---------any more than that will achieve nothing-------it is a common mistake to think that the "important" spec is amperage-------i think this comes from the assumption that in a 12 volt system the voltage is a given-------but its really not--------what you want from an alternator is electrical POWER-------and electrical power is measured in watts-------and watts are derived from amps X volts--------fog lights, driving lights, stereos aside, a stock to well modified performance GN will not ever draw more than slightly over 100 amps except when cranking the engine---------fact is that the 120 amp alternator is more than adequate for most any GN as far as amperage is concerned-------what makes a real difference is the voltage set point of the alternator and it should be considered more than amperage----------increase the amperage to 500 amps and nothing will happen--------increase the regulator voltage from 13 to 14.5 and it can make a BIG difference in fuel pump capacity, light brightness, cooling fan speed etc.--------there are lots of regulators available that fit the GN alternator (last catalogue i checked there were over 20) and the regulator set point varies quite considerably on most of them------pick an alternator that has adequate current, 120-140 is all you will ever need in a GN--------and find one that has a set point in the 14+ range and you will be making a good choice------more than 15 can be detrimental)------remember also that alternators are like engines--------a small 4 cylinder will produce 150 HP much more efficiently than a 400 cu in V8 will-------in almost all cases a 140 amp alternator will produce the power you need (approx 1960 watts) more efficiently than a larger less efficient alternator---------these simple facts are almost universally overlooked by car enthusiasts............RC
USMC_Turbo6
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So your tell me that a 140 will work fine with my car, even with a 2000w stereo, all the gagues, fan, a/c, alky kit, scanmaster, light and fuel pump upgrade and a few other staff.
salvageV6
Daily Driver
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You hadn't mentioned that, but even so, alternators do not charge well at idle, especially the high amp ones unless you put the smaller pulley on them. Additionally, alternators do not react quickly to changing loads, so the "bass hits" are most likely not going to be helped with a bigger alternator.
If you post some of the details on how your stereo system is powered, wiring, capacitors, batterys, grounding, I think Rich and others can help improve it.
Also, what symptom are you trying to cure?
Bob
USMC_Turbo6
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Well after putting in a new system which is 1000W Kenwood amp, 600W MTX amp, 2 Memphis 10, 2 5.25 Memphis doors speaker, 2 3 1/2 in dash Memphis speakers, 2 6x9 Kenwood 4 ways, Kenwood head unit, 3.5 farad capacitors, and a 2500 watt XXX wiring kit. After taking it to a local shop to have everything installed, the inside light is dimmer, window goes up slower, door locks don't want to lock, power seat moves slower, head light dimmer too, and the battery is band new. So now what?
turboc87gn
Darkside in Detroit
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Im running an impala ss 140 amp alt and i love it but i don have all the sounds you do either...I bought an oddessy die hard platinum battery and my charging probs are gone...
The sound system draws very little power when the volume is turned down, so with the volume down, are the windows still slow? Are these issues happening all the time or just with the system cranked?
Do you have a voltmeter to make some measurements with?
I assume you have a stock alternator on the car?
Bob
USMC_Turbo6
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Yes it's doing it all the time after putting in the system. I have to get a voltmeter to make some measurments and I still have to stock one on the car.
USMC_Turbo6
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any more input
use the voltmeter to measure the voltage at the alternator charging post and the battery. (with the voltmeter negative lead on the engine)
measure also the voltage between the battery negative and the engine, and the battery negative and the body.
measure with the engine idling. see what the voltage does when you operate the window, and also see if it gets any better with the engine revved slightly.
Do all this with the stereo system off.
Bob
measure also the voltage between the battery negative and the engine, and the battery negative and the body.
measure with the engine idling. see what the voltage does when you operate the window, and also see if it gets any better with the engine revved slightly.
Do all this with the stereo system off.
Bob
i can tell you for certain that your regular performance equipment amounts to very little electrical load-------and the stereo?-----depends on several things such as:-------a 1000 watt amp and a 600 watt amp are probably not much of a problem either-----a 1600 watt stereo is not really very big------assuming worst case long term duty cycle would be about 30 to 50% with distorted music and less than 15% with undistorted music--------the actual duty cycle would depend on your taste in music and how loud you play it--------then factor the duty cycle value of the music with the efficiency of the amp-----with a class A/B amp the efficiency would average about 60% if you play it distorted and less than 40% if you play it undistorted------that would equate to about 350 watts long term average power consumption WORST CASE-------if your bass amp is class D the efficiency changes drastically and you positively have no reason to be concerned--------In my grand national that was the IASCA unlimited class world champion for 5 years with an undefeated record I had five 700 watt class A/B amps (worst kind for efficiency) and it was powered by a 160 amp alternator--------never had a single problem and didn't need to change a battery the entire time it was competing--------as for the exra battery idea its generally not a good idea--------when the engine is running the battery is a load on the alternator just like it were any other accessory and more batteries actually are a detriment to a properly designed car electrical system---------extra batteries only give you more "engine off" listening time which is not really a good idea with a upgraded aftermarket stereo-------it tends to weaken the life of the battery as well as the alternator.........RC
good info rich,
his voltage is low even with the system off, so I think something's amiss irrespective of the stereo system.
the voltage measurements should tell the tale.
All the system problems he mentions (lights, windows, etc) are grounded thru the body if I remember correctly. So if his body ground connection is bad he will have lots of issues unrelated to his alternator.
Bob
his voltage is low even with the system off, so I think something's amiss irrespective of the stereo system.
the voltage measurements should tell the tale.
All the system problems he mentions (lights, windows, etc) are grounded thru the body if I remember correctly. So if his body ground connection is bad he will have lots of issues unrelated to his alternator.
Bob
x2, I had a bad preignition event last year so I upgraded all the grounds with five additional ground straps coupled with a new alternator set to NEVER drop below 14 volts and the car works flawlessly every time. Windows are fast and lights are bright too. Richard mentioned it earlier, but voltage is key, and good grounds make voltage work through the system efficiently...from my limited electrical knowledge...
