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Spoke with the guys at power master and gave their 160A alt a try.
My experience wasn't much better. Installed the 3" pulley. (which is really 2.95" going by the area the belt rides on) It had a label on it stating it was regulated to 14.8. I assumed it meant it would charge at 14.8 if needed. It charges at 14.1 for idle and cruise. I did see 14.2 at one point. The old alt would charge at 14.6+ cruising and at idle with the same pulley. On low boost I made 5 pulls and voltage held at 13.1. Not the greatest but I guess it's working ok. I turned the boost up and it leaned out again. Voltage dropped to the 11's. So maybe it is belt slip. I ordered the billet ICT manual tensioner to try. But even when not slipping the power master didn't hold a 14+ to red line, which is a bummer. I also don't have the goofy monster amp draw from my Ford Taurus fan anymore. SO the draw on the system should be very little. I noticed a .4 voltage drop from the back of the alt stud to the battery term in the trunk. So I'll add another "0 gauge" wire form the alt to the BAT. IDK what else to do. Hope you have better luck!
Spoke with the guys at power master and gave their 160A alt a try.
My experience wasn't much better. Installed the 3" pulley. (which is really 2.95" going by the area the belt rides on) It had a label on it stating it was regulated to 14.8. I assumed it meant it would charge at 14.8 if needed. It charges at 14.1 for idle and cruise. I did see 14.2 at one point. The old alt would charge at 14.6+ cruising and at idle with the same pulley. On low boost I made 5 pulls and voltage held at 13.1. Not the greatest but I guess it's working ok. I turned the boost up and it leaned out again. Voltage dropped to the 11's. So maybe it is belt slip. I ordered the billet ICT manual tensioner to try. But even when not slipping the power master didn't hold a 14+ to red line, which is a bummer. I also don't have the goofy monster amp draw from my Ford Taurus fan anymore. SO the draw on the system should be very little. I noticed a .4 voltage drop from the back of the alt stud to the battery term in the trunk. So I'll add another "0 gauge" wire form the alt to the BAT. IDK what else to do. Hope you have better luck!
Well crap. My PM does charge at 14.7-14.8 at idle.
I noticed black dust around the alt pulley, I bought a shorter belt. But I don’t have the volt drop with this car.
If you had a spare 0-5v analog input, it would be interesting to build a simple 3:1 resistor voltage divider and see what really happens right at the alt stud.
I haven't gotten to fiddle fiddle with my buddies truck that has this issue.
Just to revisit this for anyone it may help. I used a boost a pump to stop my pump worries, but never fixed the root of the problem.
The issues is alternator RPM, pure and simple. They typically stop charging around 18k RPM. You may get lucky with a nice new factory alternator over a cheapie reman, but they all do it. Buying a super BA alternator or slowing them down is the only way to fight this I'm aware of. Take your crank diameter divide by alt pulley diameter and multiply it times your max RPM. I have a 3.10" pulley. 7.5/3.10=2.4x7200= 17,419 rpm. I should be good. Haven't tested it yet, will report back.
So I recently finished a car and ran into this problem at the track. Brand new setup. Brand new alt. Car charged at 14.6 prior to taking it to the track.
After the first pass it was only charging 13.3-13.5v. And it completely quit charging at 4800rpms and up.
So I called Mechman and got to talking to them about the issue. These guys build bad *** alternators. Yesterday It a 250amp Mechman alternator arrived at my door and I threw it in my car. They claimed it could be spun 25,000rpms safely. Has a slightly larger pulley on it and Charges 180amps @ idle 😳
This thing is a beast. Since the battery is in the back they wanted a 2awg charge wire ran and and a 2awg ground run to the case of the alternator. If the battery was up front, 4awg would probably handle the amps.
Plan on going to the track this Saturday so I will let you know how it works!
So I recently finished a car and ran into this problem at the track. Brand new setup. Brand new alt. Car charged at 14.6 prior to taking it to the track.
After the first pass it was only charging 13.3-13.5v. And it completely quit charging at 4800rpms and up.
So I called Mechman and got to talking to them about the issue. These guys build bad *** alternators. Yesterday It a 250amp Mechman alternator arrived at my door and I threw it in my car. They claimed it could be spun 25,000rpms safely. Has a slightly larger pulley on it and Charges 180amps @ idle 😳
This thing is a beast. Since the battery is in the back they wanted a 2awg charge wire ran and and a 2awg ground run to the case of the alternator. If the battery was up front, 4awg would probably handle the amps.
Plan on going to the track this Saturday so I will let you know how it works!
Good to hear... What did that Alt. cost? I honestly don't need or want a 25hp draw from my alternator! lol. Wish they made a 100a unit that performed the same at half the price. I just can't see ever needing that kind of power on a drag car!
Good to hear... What did that Alt. cost? I honestly don't need or want a 25hp draw from my alternator! lol. Wish they made a 100a unit that performed the same at half the price. I just can't see ever needing that kind of power on a drag car!
$400 😳 And I get the same. But voltage drop to me seems like a pretty critical issue and I just wanted to take care of it once and for all lol. It didn’t effect the car/fueling going down the track but I’m not leaning on it yet.
Just add a little boost to make up for the 25hp alternator draw 😉
Originally Posted by stevieturbo
If there is nothing to draw the current, then it will not be creating it.
it can't simply pump 180A where there is nowhere to pump it.
I suppose this would be true. I’m not a alternator guy (in fact I don’t know a damn thing about them lol). But if your doing a blast down the track with 60amps worth of fans running.. two big fuel pumps, lights (night race), etc etc etc... this alt will meet all that demand with headroom.
I have 4awg welding cable ran from the alt back to the battery and they want it bigger 😳. I really don’t wanna re wire a brand new car either.
$400 😳 And I get the same. But voltage drop to me seems like a pretty critical issue and I just wanted to take care of it once and for all lol. It didn’t effect the car/fueling going down the track but I’m not leaning on it yet.
Just add a little boost to make up for the 25hp alternator draw 😉
I suppose this would be true. I’m not a alternator guy (in fact I don’t know a damn thing about them lol). But if your doing a blast down the track with 60amps worth of fans running.. two big fuel pumps, lights (night race), etc etc etc... this alt will meet all that demand with headroom.
I have 4awg welding cable ran from the alt back to the battery and they want it bigger 😳. I really don’t wanna re wire a brand new car either.
No reason at all to have fans running over say 30mph ( unless rad is in the rear of the car or something )
On load, during racing, I'd be surprised if most cars would actually be pulling more than 50-60A, unless it had some really insane fuel system and pumps.
Of course, plenty of CT options to log current too.
No reason at all to have fans running over say 30mph ( unless rad is in the rear of the car or something )
On load, during racing, I'd be surprised if most cars would actually be pulling more than 50-60A, unless it had some really insane fuel system and pumps.
Of course, plenty of CT options to log current too.
I’d have to have a speed sensor to turn them off at a given mph lol. And I/O is scarce on the Holley Terminator! It is a 4th gen without a air damn so it probably need the fans on anyway. 20-22amps from each of these derale pushers when on high though they are on low most the time.
A Walbro 450 will pull over 20amps by itself at 4bar+ fuel pressure. So there’s 40amps just in the 2 fuel pumps. 40amps with fans if on high. So 80amps Then there’s the trans cooler fan, engine, and body stuff.
I think the kg3 (or whatever) truck alternator is way more than enough. It’s just those rpms. I didn’t wanna buy a $200 alt to chunk it again when I sleep on the shift or bounce the limiter coming out the burn out box. They said this the cheapest one we got (for the high rpms) but guarantee it’ll solve my my issues. So here I am lol
Does that mean you're using the stock AC tensioner for the alt?
Yes, and I hate it. I think I finally found a belt tight enough that it doesn't jump off or turn on the pulley. No one makes a manual tensioner that I am aware of.
So I recently finished a car and ran into this problem at the track. Brand new setup. Brand new alt. Car charged at 14.6 prior to taking it to the track.
After the first pass it was only charging 13.3-13.5v. And it completely quit charging at 4800rpms and up.
So I called Mechman and got to talking to them about the issue. These guys build bad *** alternators. Yesterday It a 250amp Mechman alternator arrived at my door and I threw it in my car. They claimed it could be spun 25,000rpms safely. Has a slightly larger pulley on it and Charges 180amps @ idle 😳
This thing is a beast. Since the battery is in the back they wanted a 2awg charge wire ran and and a 2awg ground run to the case of the alternator. If the battery was up front, 4awg would probably handle the amps.
Plan on going to the track this Saturday so I will let you know how it works!
The vette guys are having a bunch of issues with Mechman Alternators. One of the main reasons I decided to try the one I got from JS Alternators. DC power is another brand that people seem to have good luck with but it's in the $500-$600 range.
Hmmmmm so I believe I'm having an alternator charge issue as well. I pulled my dyno log from a few months ago and thankfully it maintained perfect AFR, but the fuel pressure had some big sudden drops but then came right back. I realized I didn't have battery voltage on the log so I added it and re looked at the data log and it dropped all the way to 11.9. I believe it is an RPM issue as it charges at 14.1-14.2 at idle. I'm doing a bunch of research right now on what to do, but there don't seem to be any sure fire fixes. All I've read about is some people having good luck and others not. I'm leaning towards the JS Alternator that jayyyw is using. 250 amp for $299 seems like a pretty solid deal. Thoughts?
The vette guys are having a bunch of issues with Mechman Alternators. One of the main reasons I decided to try the one I got from JS Alternators. DC power is another brand that people seem to have good luck with but it's in the $500-$600 range.
Interesting.. it was about 6 different vette guys that told me it solved all their problems. That’s how I found them lol
The vette guys are having a bunch of issues with Mechman Alternators. One of the main reasons I decided to try the one I got from JS Alternators. DC power is another brand that people seem to have good luck with but it's in the $500-$600 range.
Well it worked flawlessly... till it didn’t. Went up in smoke. I’ll update you guys after I talk to them Monday
I didn’t spend that much. But it was more than enough to be hot.
ill see what they do. They have a pretty solid reputation. There’s always the douchebag move and do a charge back. I’ll give them a chance to figure it out though.
put the factory alternator back on and dealt with 13.3v and it stopping charging at 4800 for the day
07-13-2020, 07:43 AM
