2.9 B2 alternator questions

[Surrey]

What is the amperage on a 2.9l Alternator?
I understand there is more than one alternator used, but I can't find much for details on the matter.
My truck has A/C and power windows/locks.

Also, is there bolt-in JY alternatives that put out more? From what I've read around here, 4.0 alts dont fit, and I can't find anything that says what will.

Thanks.

 

[4.0B2]

4.0 runs a serpentine belt. idk about your 89 2.8, but my 88 was v-belt.
autozone shows the 88 2.9 at 65 amps..
the 89 shows a 60 and 85 amp for the 2.9

 

[Surrey]

Can someone clarify my math is right on this please?

55w bulb x2 lights /12 volts = 9.16 amps drawn.

Stock headlights draw about 55w, right?
Does anyone know draw for brake lights?

and for an aftermarket CD deck, something like...

50wx4 channels / 12 volts=16.6 amps drawn.

 

[adsm08]

I can't remember all the ratings on the 2.9 Alternators, but I do remember that when I replaced mine the guy at NAPA was able to figure it out by the number and position of the bolts that hold it to the bracket.


A 4.0 alternator prolly won't work. They mount differently since the 4.0 has always used serp belts and the 2.9 (AFAIK) always had V-belts.

 

[holyford86]

I'm running a large case 3G out of a taurus, Stock they put out 130 amps and had a serpentine belt. I swapped a v belt pulley onto it and made a bracket for the upper bolt, then i had it rebuilt to 200A

 

[Duane867]

Over the years rangers and BII's with the 2.9L came with 40, 60, 65, 75, 80 and I "think" 90 amp alternator options.

 

[Surrey]

What is there for options for a bolt-in replacement for my 2.9?
Swapping a pulley is fine, but thats about as much work as I am wanting (hoping) to do.

 

[Earl43P]

I didn't look very hard and found an 80 amp on the first of 3 pages worth of hits....bolt-in replacement, correct v pulley. I used "Eddie Bauer", figuring that would have had the most options drawing power. I'm sure if you took the old one into Napa or the Canadian equivalent of a good AP store, they could fix you right up. Matching connections, clock angle, mount method (swivel) and pulley type. Shouldn't be too hard for a good parts guy, even if you have to swap a pulley or change the clock angle, easy work.


NSA Alternator
For 1989 Ford Bronco II Eddie Bauer 6 Cyl 2.9L
Zoom
* Features
* Description

Features
Brand: NSA
Color/Finish: Natural
Condition: New
Amperage Output: 80
Product Fit: OE replacement
Regulator Style: Internal
Warranty: 2-year NSA warranty
view more
Description
NSA ALTERNATOR, NEW -- 80 amps output, 12 V, internally regulated, clockwise rotation, 2 o'clock position; Replaces OE Ford unit; No core re.....
view more
PART#: USALT-F060
MFR#: ALT-F060

From: http://www.partstrain.com/store/ind...966460&Nr=AND(universal:0)&N=0&Ntt=alternator


Here's some 3G's showing mount methods and clock angles as a reference. http://www.rjminjectiontech.com/?p=6

 

[4.0B2]

$80 aint bad either...
next alternator i get will be a JY one rebuilt by a local guy to have more output!

i paid $13 for my alternator. its from a jy.. and i'm thinking of getting the EB ex's one (it will fit mine) and have 130 amps.

but getting one rebuilt is always an option.
or meangreen alternators! lol

 

[Surrey]

I dont *need* an alternator. In fact, I have two of them, the one in my 89, and one out of an 88 that had AC, p/w/locks.

Im just looking for something better to run lights and shit, something like 110amps would probably be tonnes.

That being said, with an 80 amp alt, I can get a grand total of 960 watts... Right? (80x12=960)

So I was thinking...
200 stereo
55 headlights
55 tail lights (no idea, total guess.)
110 driving lights (1 pair)
110 fog lights (1 pair)
110 fog on the back (1 pair)
=640 watts.

I have no idea what sort of draw all the other things have though... Power windows/locks, dome light, dash lighting... What else am I missing?

With the math I am coming up with, it seems that two sets (4 total) of 55w lights up front, and a pair in the back should be plenty manageable with an 80amp alternator... Does anyone have experience running this much on an alternator of this size? Am I just blowing smoke up my arse thinking I can get away with all that?

Thanks.

 

[gwaii]

your output will be a bit higher than you figured on...use 14.7 as the voltage in your computations.

 

[gwaii]

also,some kinda important things to figure on the 'use' side are fuel pump,ignition system,computer.without those,alternator output will be less than optimum.

intermittent loads like power windows can be ignored for the most part.

 

[Surrey]

also,some kinda important things to figure on the 'use' side are fuel pump,ignition system,computer.without those,alternator output will be less than optimum.

intermittent loads like power windows can be ignored for the most part.

Well see now that is where I am stuck. I cant think of (and probably dont know) all the things I need to consider, like the computer and fuel pump and injectors and sensors and whatever else has any amount of power draw... And even if I could think of them all, I still have no idea how much power these things draw.

Does anyone know of an approximate baseline that a Bronco2 draws for those basic functions or anything?
Would it be safe to say 40amps is enough to run everything truck-wise, other than lighting? Maybe higher, maybe lower??

Thanks.

 

[gwaii]

Would it be safe to say 40amps is enough to run everything truck-wise, other than lighting?

that would keep you well on the safe side.

 

[Surrey]

that would keep you well on the safe side.

Ok thanks. Until I have a better understanding of the loads involved, I will go with that then.