Vintage Mustang Forums banner

1 - 20 of 29 Posts

·
Registered
Joined
·
363 Posts
Discussion Starter #1
I’m on the fence between getting a 100 of 150 amp alternator for my mustang. I’m looking at the PowerMaster as it looks somewhat period correct. I’m not a “stereo” guy, but I have electronic ignition, halogen type stock headlights, and the reason I am considering the upgrade, is because I’m thinking of adding an electric fan, and possibly an electric fuel pump. I’m not sure where I’ll land with the electric fan (I’m trying to figure out how to stick something in the stock shroud), but I know a Taurus fan can pull a steady 30 Amps, so I’d like to have room for that option.

The only reason NOT to go to the 150 Amp PowerMaster, from what I can tell, anyway, is that belt-slip could become an issue. I have considered going 3G, but PA won’t even sell the 130 Amp version for a single v-belt system, and I also think they look just a touch too modern for my personal tastes.

Is 100 Amps going to be sufficient? Is belt slippage really that big of an issue for a 150 Amp alternator with the type of load my system will see?

Thanks, as always, for the advice.

Casey
 

·
Registered
Joined
·
800 Posts
Cars in the early 90s had 105 amp alternators (some less in the 90amp range) and did just fine and they had higher loads than your mustang. They were running dual fans, fuel pump, ecm, abs and on and on.

Also many times there is a tradeoff with the higher amp alternators. Many say 140 amp ones will put out less at idle than say a 100 amp version. You need to output curve of the alternator to really know but it is a general rule.
 

·
Registered
Joined
·
1,086 Posts
Another side effect of the high current alternators is you can get belt squeal at startup when it jumps into high charge mode(3G).
 

·
Registered
Joined
·
393 Posts
You might call a place called DB electrical. (I think you can find them on the inter-web) I had trouble with 2 Power Master alternators before calling these people. They built me a 1 wire alternator that looks old-school, they assisted me in choosing the correct amperage, and they saved me money over the inferior products that I had bought before. I am as happy as can be with the product, and it has worked perfectly. Disclaimer; I am in no way affiliated with DB electrical.
 

·
Registered
Joined
·
532 Posts
"Mustang Charlie", an old-timer Mustang afficiando in this area, said there is a local guy who will rewind the stock alternator to give just under 100amps -- so you retain the original look. He said that you can't get much more amperage than 100A with the present size case.
So there must be someone in your area who also can do this.

One point he made is that you can be assured of the new amperage, and that parts are 100% American (aka "done right").
 

·
Just some guy
67 coupe, 69 Sportsroof, 86 hatchback
Joined
·
20,634 Posts
Most people focus on the peak amp rating even though they (and I) will never really use an alternator at its maximum output. More important to me is how much power one can make at low to idle RPM's. I'll take a 95 amp 3G over a Delco "1 wire" or any stock or converted 1G Ford alternator any day. Because I know what it's like to be stuck in traffic at night in the rain. With an alternator that doesn't really have a decent output unless the engine is above 1500 RPM or so. It sucks. Dim headlights, fan speed dragging, and if you have to stop somewhere, a little prayer that the battery is strong enough to restart the car.
Because the old school Ford and GM alternators just can't handle that scenario very well and never did. Even the large case 1G's weren't good at idle speeds. The 3G's and 4G's shine at that. But unfortunately I do agree, they look more than a little out of place under a vintage hood. You have to pick your compromises. The 1G's and Delco's aren't actually bad and DO look correct underhood.
 

·
Premium Member
Joined
·
13,178 Posts
the OP can run all of his stated equipment on the 62 amp remanufactured units that come in the stock AutoLite teardrop case.

That said, as GypsyR points out, the max output doesn't really come into play here. If the OP is set on getting one of the high output units, the 100 amp unit will more than suffice.

Z.
 

·
Registered
Joined
·
60 Posts
Turning on the A/C compressor seems to be the biggest load on my Power master 140 amp alternator. More than when using electric fan, stereo amps and the fuel pump combined. Though I am not measuring amp draw, the alternator provided voltage would drop from the typically normal 13.5v to 12.0v. And it could be lower than 12.0v at an lower cold A/C setting which I never use. Driving without A/C in certain locations half the year in the southwest is not an option.
 

·
Registered
Joined
·
35,869 Posts
My vote is for a 95A small-case 3G. Should be a direct bolt-in, minimal wiring changes (elimination of external regulator), v-belt capable. Replacement halogens don't use any more "juice" than stock incandescents, electronic ignition is good for about 5-8A more than stock.

IMHO, electronic fuel pump is unnecessary unless swapping to EFI or if you have the need to run a Dominator or big blower... electric cooling fan unnecessary unless limited in fan-to-radiator clearance.
 

·
Registered
Joined
·
35,869 Posts
Turning on the A/C compressor seems to be the biggest load on my Power master 140 amp alternator. More than when using electric fan, stereo amps and the fuel pump combined. Though I am not measuring amp draw, the alternator provided voltage would drop from the typically normal 13.5v to 12.0v. And it could be lower than 12.0v at an lower cold A/C setting which I never use. Driving without A/C in certain locations half the year in the southwest is not an option.
The A/C compressor clutch should be drawing 3-5 amps. You're probably mistaking electrical load with parasitic load on the engine, causing a reduction in rpm and, thus, generating capability.
 

·
Registered
Joined
·
938 Posts
Most experience belt squeal with higher amp 3G's and V belts. It annoyed me so much on my PA 100 amp that I've got a CVF serpentine kit on the way.

3G is the way to go though.
 

·
Premium Member
Joined
·
481 Posts
First I would leave the electric fans at the store. Not much is going to be as effective as the mechanical unless your engine is designed for spinning hi rpms or your engine compartment is space limited.100 amp alternators are about all I'll put on with a v-belt.and its plenty. In gerneral most all modern high current draw vehicles will idle fully loaded at 75 amps output or so.Try not to over think it. Also large capacity batteries will maintain a decent reserve sitting at red lights with regards to to the old stuff. And Fords charging systems had been poor as GypsyR mentioned for decades. So maintaining a low current foot print was/is key. I see guys spending thousands in this department on low hp projects and mostly nothing can change their thoughts on the subject either.
 

·
Registered
Joined
·
363 Posts
Discussion Starter #16
I wanted to, and often try, to respond to all the commenters when I make a post, but this one got away from me. Definitely some varied opinions, but more votes, for smaller output alternators which I find relieving. I actually just found a brand new 65 Amp Autolite Reman unit in a box in my rafters that’s been up there for at least a decade. I also found a multi-rib pulley set in the same box (that I will be listing in the classifieds), so late-2000’s me was evidently contemplating these same questions. The main reasons I was contemplating the higher output PowerMaster units was because they advertise something like 75 and 100 amps at idle, but it sounds like they might not actually output that amperage AT idle? Interesting...

First I would leave the electric fans at the store. Not much is going to be as effective as the mechanical unless your engine is designed for spinning hi rpms or your engine compartment is space limited.100 amp alternators are about all I'll put on with a v-belt.and its plenty. In gerneral most all modern high current draw vehicles will idle fully loaded at 75 amps output or so.Try not to over think it. Also large capacity batteries will maintain a decent reserve sitting at red lights with regards to to the old stuff. And Fords charging systems had been poor as GypsyR mentioned for decades. So maintaining a low current foot print was/is key. I see guys spending thousands in this department on low hp projects and mostly nothing can change their thoughts on the subject either.
I think you guys have effectively talked me into keeping my clutch fan. But what is considered the practical RPM limit for a clutch fan? This motor regularly sees 6,000, and I plan on doing some track days this year. That, and the fact that I am about to replace the radiator for the third time due to defects, and each time I have had to make modifications it for the stock fan shroud to fit properly...I just thought it might be easier to bolt on an electric fan, and benefit from a few added ponies at the same time.
 

·
Premium Member
Joined
·
481 Posts
If racing is in your future I would beef up the cooling system and would continue on with your original plans then. Typically speeds over 35 mph and no a/c on a radiator gets plenty of air across it to remove heat in a passenger car. Racing (not drag racing) will exploit the short comings in any system. Also negitive hp has no home in racing when a getting all power as possible to the ground is key. So a heavy constantly rotating fan killing 18+ hp at racing rpm should be replaced in a racing invironment for sure.
 

·
Registered
Joined
·
35,869 Posts
What year and vehicle 3G 95 amp alternator would you guys recommend?
Small case 3G 95A with correct clocking and correct regulator. Some have incorrect 2 groove pulley, some have correct 6 groove:
92-94 3.0L Aerostar (early 92s were 2G not 3G, so check before you buy)
96-97 F series pickup with a 7.5L
 

·
Registered
Joined
·
35,869 Posts
I wanted to, and often try, to respond to all the commenters when I make a post, but this one got away from me. Definitely some varied opinions, but more votes, for smaller output alternators which I find relieving. I actually just found a brand new 65 Amp Autolite Reman unit in a box in my rafters that’s been up there for at least a decade. I also found a multi-rib pulley set in the same box (that I will be listing in the classifieds), so late-2000’s me was evidently contemplating these same questions. The main reasons I was contemplating the higher output PowerMaster units was because they advertise something like 75 and 100 amps at idle, but it sounds like they might not actually output that amperage AT idle? Interesting...



I think you guys have effectively talked me into keeping my clutch fan. But what is considered the practical RPM limit for a clutch fan? This motor regularly sees 6,000, and I plan on doing some track days this year. That, and the fact that I am about to replace the radiator for the third time due to defects, and each time I have had to make modifications it for the stock fan shroud to fit properly...I just thought it might be easier to bolt on an electric fan, and benefit from a few added ponies at the same time.

740466
 
1 - 20 of 29 Posts
Top