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HO alternator issue


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Having some trouble with my HO alternator, and I think I've exhausted interactions with the company

***Please keep in mind the following conditions are without subs. I removed the system for now till I decide on my next subs/box. The highs amp is playing and the lows amp (DD M3b) is only turned on but not hooked up to subs.

stock alternator -14.5 at cold start, then levels off around 14.4-14.3 in the morning. While driving around, (RPM 1500-2k) the lowest I've seen out of it was 13.9 and this is driving for a decent amount of time on a fairly warm day. At idle its usually 13.9-14.0.

HO alternator (240a hairpin) - 14.8 cold start, then steadily drops to 12.7-12.8 idle. While driving around, (again RPM 1500-2k) it can reach 14.4-.6...but soon as I stop at a long light or busy stop sign, I can watch it drop to 12.2-12.3 which concerns me...remember, this is without running subs.

I've gone back and forth with the company about it and they were very nice...sent me a pulley that was 1-7/8" instead of the 2-5/8" it came with. But that just improved the idle voltage while in park (it originally was 12.3 at idle instead of 12.7-.8). To my understanding, my car is drive by wire so I can't adjust the idle rpm higher; Im told its pretty low (550). I was also told by the company that running an external regulator wouldn't help me; and I've read (from power bastards FAQ) that my car's crank pulley is on the small side (5-1/4"). 

I guess I'm asking for insight on how a high output works and why it seems to not be able to charge unless its in high RPMs. I thought the batteries would be able to hold somewhat of a charge over 12 volts? Is there nothing else I can do to make this thing work? I've tried to see if the PCM controlled the output by turning on heat and headlights, but the voltage just drops more. My Honda had a small crank and idled low, but the HO alt I put in it didn't seem to have the same problems this one does.

I don't get it, and I'm afraid I have a $500 paperweight.

 

 

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I had the same problem. I turned my idle down to about 550rpm so it would have a nice lopey sound when idling. Its a 460 big block and when I installed the HO alt, it wouldn't charge even with the small pulley. I had to turn the idle up to about 750rpm and now it does good except when the AC is on. It seems that the output increase comes at the expense of low end output. I plan on installing a second stock alternator at some point. The only way to get it to spin faster would be to get an even smaller pulley for the alt which will be hard to do. Or increase the crank pulley size. What car do you have? Maybe the program in the cars computer can be changed to raise the idle speed?

91 C350 Centurion conversion ( Four Door One Ton Bronco)

250A Alternator (Second Alternator Coming Soon)

G65 AGM Up Front  / Two G31 AGM in Back

Pioneer 80PRS

CT Sounds AT125.2 / CT Sounds 6.5 Strato Pro component Front Stage

CT Sounds AT125.2 / Lanzar Pro 8" coax w/compression horn tweeter Rear Fill

FSD 5000D 1/2 ohm (SoundQubed 7k Coming Soon)

Two HDS315 Four Qubes Each 34hz (Two HDC3.118 and New Box Coming Soon)

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14 minutes ago, ShadeTreeMechanic said:

I had the same problem. I turned my idle down to about 550rpm so it would have a nice lopey sound when idling. Its a 460 big block and when I installed the HO alt, it wouldn't charge even with the small pulley. I had to turn the idle up to about 750rpm and now it does good except when the AC is on. It seems that the output increase comes at the expense of low end output. I plan on installing a second stock alternator at some point. The only way to get it to spin faster would be to get an even smaller pulley for the alt which will be hard to do. Or increase the crank pulley size. What car do you have? Maybe the program in the cars computer can be changed to raise the idle speed?

good suggestions man thank you, the car is an '04 impreza wagon. Can't change the crank size because I've read horrible stories on the harmonic balancing of this motor (2.5 N/A) and some losing their bottom end from lightweight pulleys...I'll look around for a smaller alt pulley but I don't know if it can get much smaller with this shaft. I've heard the tuning programs like an Accessport for the wrx/sti's have the option to raise idle speed, but those are around 4-500 bucks...Would definitely try it, but only if I could pick one up for cheap. 

AA-Atomic-Clif Designs-DC-Diamond-Digital Designs-Directed-Eclipse-Fi-Hertz-Hifonics-Kenwood-Memphis-Phoenix Gold-Pioneer-PPI-PSi-Stinger-Sundown-TC Sounds-Viper-Zapco

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Since it is fly by wire, I don't suppose there would be an adjustment on the gas pedal?

91 C350 Centurion conversion ( Four Door One Ton Bronco)

250A Alternator (Second Alternator Coming Soon)

G65 AGM Up Front  / Two G31 AGM in Back

Pioneer 80PRS

CT Sounds AT125.2 / CT Sounds 6.5 Strato Pro component Front Stage

CT Sounds AT125.2 / Lanzar Pro 8" coax w/compression horn tweeter Rear Fill

FSD 5000D 1/2 ohm (SoundQubed 7k Coming Soon)

Two HDS315 Four Qubes Each 34hz (Two HDC3.118 and New Box Coming Soon)

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Higher output alts typically dont turn on until a certain amount of rpms. So at a stop light with low idle the alt would essential turn off if no draw/load is seen.
Also the higher the amperage alternator, the less it will make at idle output. Though the hairpin technology yields much better results than the standard wound style stator. Granted this is irrelevant if the alternator is turning off at lower speeds.
So now if your alternator is turning off at low rpms this means your entire vehicle is running off battery power at those times and the reason your battery is dropping to the 12volt range when parked, stopped, or moving slowly.

Sometimes you can fix this issue by going to a even smaller underdrive pulley on the alternator if you already dont have the smallest one made, granted you will need to make sure you have excellent belt wrap since you would have less belt on pulley contact which could make it easier to slip under demanding loads.
I know you said they sent you a smaller pulley, but I am not aware if thats the smallest you can go or not, maybe another manufacture has smaller ones Im not sure.

As for going to an external regulator this would do nothing in your case, because the alternator would still only turn on when the rpms are high enough. All the regulator would do is allow you to change your charge voltage, so if your oem computer controlled the charge voltage and it was too low then the external would help.
Now if your alternator is indeed by your cars computer, and that computer is programmed to turn the alternator off at lower rpms when your stopped or parked to increase fuel economy then a external regulator may help.
But say if it was and you did this swap you would then have the idiot battery light illuminated on your dash so you would have to trick the computer with a resistor to get that light turned off, or pull out the bulb in the instrument cluster, or put some black electrical tape over it if those idiot lights drive you nuts.

I would contact the builder and see what rpm the alternator is to turn on at, and then as if that is engine rpms or alternator rpms. Those are 2 different rpms and its usually a 2-3:1 ratio (the alt spinning 2-3 times per 1 engine revolution), but this can be slightly different from vehicle to vehicle.
So another option would be taking the vehicle to someone who has a nice scan tool, or a speed shop that has a dyno which has the ability to program the ecu. You can then have the idle rpms raised permanently that way since its a fly by wire vehicle.
Chances are your alternator is NOT a paper weight, but the issue is with the cars computer one way or another and how it controls the alternator.

Lastly not to scare you, if your sub amp has nothing hooked up to it and its being turn on when ever your driving your at risk for blowing it. Something about amps that just dont being like left on unloaded, or even loaded but volume muted. Ive blown a few this way just sitting in the drive through waiting to order food. So I would really pull the remote wire off the amp until your ready to use it.

 

 

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3 hours ago, ShadeTreeMechanic said:

Since it is fly by wire, I don't suppose there would be an adjustment on the gas pedal?

I read another thread on someone who tried to do it....and it seems that even the thinnest material he could find (I think he said he tried a vinyl sticker) would send the rpms up to 1500...however, I ran outside to take a closer look at it and seems my year was right before the drive by wire (all year ranges Ive found say otherwise; but when I was looking at free software they have for mapping an ECU image, my year wasn't on there). There is a throttle cable, decently hidden to the left of the brake booster for a few inches, then it dives underneath a few vacuum, fuel, and ac lines. I'm gonna get out there tomorrow and see what I can do with it...maybe I can land on 750 rpm.

2 hours ago, audiofanaticz said:

Higher output alts typically dont turn on until a certain amount of rpms. So at a stop light with low idle the alt would essential turn off if no draw/load is seen.
Also the higher the amperage alternator, the less it will make at idle output. Though the hairpin technology yields much better results than the standard wound style stator. Granted this is irrelevant if the alternator is turning off at lower speeds.
So now if your alternator is turning off at low rpms this means your entire vehicle is running off battery power at those times and the reason your battery is dropping to the 12volt range when parked, stopped, or moving slowly.

Sometimes you can fix this issue by going to a even smaller underdrive pulley on the alternator if you already dont have the smallest one made, granted you will need to make sure you have excellent belt wrap since you would have less belt on pulley contact which could make it easier to slip under demanding loads.
I know you said they sent you a smaller pulley, but I am not aware if thats the smallest you can go or not, maybe another manufacture has smaller ones Im not sure.

As for going to an external regulator this would do nothing in your case, because the alternator would still only turn on when the rpms are high enough. All the regulator would do is allow you to change your charge voltage, so if your oem computer controlled the charge voltage and it was too low then the external would help.
Now if your alternator is indeed by your cars computer, and that computer is programmed to turn the alternator off at lower rpms when your stopped or parked to increase fuel economy then a external regulator may help.
But say if it was and you did this swap you would then have the idiot battery light illuminated on your dash so you would have to trick the computer with a resistor to get that light turned off, or pull out the bulb in the instrument cluster, or put some black electrical tape over it if those idiot lights drive you nuts.

I would contact the builder and see what rpm the alternator is to turn on at, and then as if that is engine rpms or alternator rpms. Those are 2 different rpms and its usually a 2-3:1 ratio (the alt spinning 2-3 times per 1 engine revolution), but this can be slightly different from vehicle to vehicle.
So another option would be taking the vehicle to someone who has a nice scan tool, or a speed shop that has a dyno which has the ability to program the ecu. You can then have the idle rpms raised permanently that way since its a fly by wire vehicle.
Chances are your alternator is NOT a paper weight, but the issue is with the cars computer one way or another and how it controls the alternator.

Lastly not to scare you, if your sub amp has nothing hooked up to it and its being turn on when ever your driving your at risk for blowing it. Something about amps that just dont being like left on unloaded, or even loaded but volume muted. Ive blown a few this way just sitting in the drive through waiting to order food. So I would really pull the remote wire off the amp until your ready to use it.

thank you for all the information! I'll have to search for a smaller pulley; although the belt wrap isn't the greatest on these engines...looks like around 40% or so. I ran outside to check the motor again, and it appears this isn't a drive by wire (all the model year ranges say it's included) I found the throttle cable. Hopefully I can adjust it tomorrow and get a couple hundred rpms out of it. But I don't know if the ECU will reconfigure itself to support it. If that doesn't work, I'll call up a performance shop in the area to see if they can do it...theres one not too far that specializes in wrx and stis. 

and when I went out to check the motor, I pulled the amp's remote line. ?

2 hours ago, audiofanaticz said:

And a quick google search I found you a simple fix it looks like.

Seems to be exactly the issue you described.

http://strongforsubaru.com/subaru-alternator-fault-fix/
 

 

I don't think this fix will work for me only because my harness is a 3 pin, however there's only 2 wires. I don't have the blue sense wire...which would probably mean the computer doesn't control the alternator right? And the stock alternator doesn't drop voltage like the HO does. The voltage stays right around high 13s to low 14s pretty much all the time (without the system) with the stock one in.

Whether I can do it by the cable or talk to the shop, it sounds like raising RPMs is gonna be the best approach. Thank you again!

AA-Atomic-Clif Designs-DC-Diamond-Digital Designs-Directed-Eclipse-Fi-Hertz-Hifonics-Kenwood-Memphis-Phoenix Gold-Pioneer-PPI-PSi-Stinger-Sundown-TC Sounds-Viper-Zapco

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